[Federal Register Volume 72, Number 224 (Wednesday, November 21, 2007)]
[Notices]
[Pages 65615-65629]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-22738]
-----------------------------------------------------------------------
NUCLEAR REGULATORY COMMISSION
Notice of Opportunity To Comment on Model Safety Evaluation on
Technical Specification Improvement for B&W Reactor Plants To Risk-
Inform Requirements Regarding Selected Required Action End-States Using
the Consolidated Line Item Improvement Process
AGENCY: Nuclear Regulatory Commission.
ACTION: Request for comment.
-----------------------------------------------------------------------
SUMMARY: Notice is hereby given that the staff of the Nuclear
Regulatory Commission (NRC) has prepared a model safety evaluation (SE)
and model license amendment request (LAR) relating to changes to the
end-state requirements for required actions in B&W reactor plants'
technical specifications (TS). Current technical specification action
requirements frequently require that the unit be brought to cold
shutdown when the technical specification limiting condition for
operation for a system has not been met. Depending on the system, and
the affected safety function, the requirement to go to cold shutdown
may not represent the most risk effective course of action. In
accordance with a qualitative risk analysis that provides a basis for
changes to the action requirement to shutdown, where appropriate the
shutdown end-state is changed from cold shutdown to hot shutdown. The
affected TS are:
3.3.5 Engineered Safety Feature Actuation System (ESFAS)
Instrumentation.
3.3.6 ESFAS Manual Initiation.
3.4.6 Reactor Coolant System (RCS) Loops--MODE 4.
3.4.15 RCS Leakage Detection Instrumentation.
3.5.4 Borated Water Storage Tank (BWST).
3.6.2 Containment Air Locks.
3.6.3 Containment Isolation Valves.
3.6.4 Containment Pressure.
3.6.5 Containment Air Temperature.
3.6.6 Containment Spray and Cooling Systems.
3.7.7 Component Cooling Water System.
3.7.8 Service Water System.
3.7.9 Ultimate Heat Sink.
3.7.10 Control Room Emergency Ventilation System (CREVS).
3.7.11 Control Room Emergency Air Temperature Control System
(CREATCS).
3.8.1 AC Sources--Operating.
3.8.4 DC Sources--Operating.
3.8.7 Inverters--Operating.
3.8.9 Distribution Systems--Operating.
The NRC staff has also prepared a model no significant hazards
consideration (NSHC) determination relating to this matter. The purpose
of these models is to permit the NRC to efficiently process amendments
that propose to adopt technical specification changes, designated as
TSTF-431, Revision 2, related to Topical Report BAW-2441, Revision 2,
``Risk Informed Justification for LCO End-State Changes,'' September
2006. Licensees of B&W nuclear power reactors to which the models apply
could then request amendments utilizing the models and justifying the
applicability of the SE and NSHC determination to their reactors. The
NRC staff is requesting comments on the model SE, model LAR, and model
NSHC determination prior to announcing their availability for
referencing in license amendment applications.
DATES: The comment period expires December 21, 2007. Comments received
after this date will be considered if it is practical to do so, but the
Commission is able to ensure consideration only for comments received
on or before this date.
ADDRESSES: Comments may be submitted either electronically or via U.S.
mail.
Submit written comments to Chief, Rules and Directives Branch,
Division of Administrative Services, Office of Administration, Mail
Stop: T-6 D59, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001. Hand deliver comments to: 11545 Rockville Pike, Rockville,
Maryland, between 7:45 a.m. and 4:15 p.m. on Federal workdays. Copies
of comments received may be examined at the NRC's Public Document Room,
11555 Rockville Pike (Room O-1F21), Rockville, Maryland. Comments may
be submitted by electronic mail to [email protected].
FOR FURTHER INFORMATION CONTACT: Timothy Kobetz, Mail Stop: O-12H2,
Technical Specifications Branch, Division of Inspection & Regional
Support, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory
Commission, Washington, DC 20555-0001, telephone 301-415-1932.
SUPPLEMENTARY INFORMATION:
Background
Regulatory Issue Summary 2000-06, ``Consolidated Line Item
Improvement Process for Adopting Standard Technical Specification
Changes for Power Reactors,'' was issued on March 20, 2000. The
consolidated line item improvement process (CLIIP) is intended to
improve the efficiency of NRC licensing processes, by processing
proposed changes to the standard technical specifications (STS) in a
manner that supports subsequent license amendment applications. The
[[Page 65616]]
CLIIP includes an opportunity for the public to comment on proposed
changes to the STS after a preliminary assessment by the NRC staff and
finding that the change will likely be offered for adoption by
licensees. The CLIIP directs the NRC staff to evaluate any comments
received for a proposed change to the STS and to either reconsider the
change or announce the availability of the change for adoption by
licensees. Licensees opting to apply for this TS change are responsible
for reviewing the staff's evaluation, referencing the applicable
technical justifications, and providing any necessary plant-specific
information. Each amendment application made in response to the notice
of availability will be processed and noticed in accordance with
applicable NRC rules and procedures.
This notice solicits comment on changes to the end-state
requirements for required actions, if risk is assessed and managed, for
the primary purpose of accomplishing short-duration repairs which
necessitated exiting the original Mode of operation. The change was
proposed in Topical Report BAW-2441, Revision 2, ``Risk Informed
Justification for LCO End-State Changes,'' September 2006. This change
was proposed for incorporation into the standard technical
specifications by the owners groups participants in the Technical
Specification Task Force (TSTF) and is designated TSTF-431, Revision 2.
TSTF-431, Revision 2, can be viewed on the NRC's web page at http://www.nrc.gov/reactors/operating/licensing/techspecs.html.
Applicability
This proposal to modify technical specification requirements by the
adoption of TSTF-431, Revision 2, is applicable to all licensees of B&W
plants. To efficiently process the incoming license amendment
applications, the staff requests that each licensee applying for the
changes proposed in TSTF-431, Revision 2, include Bases for the
proposed TS consistent with the Bases proposed in TSTF-431, Revision 2.
To efficiently process the incoming license amendment applications, the
staff requests that each licensee applying for the changes proposed in
TSTF-431, Revision 2, use the CLIIP. Licensees are not prevented from
requesting an alternative approach or proposing the changes without the
requested Bases and Bases control program. Variations from the approach
recommended in this notice may require additional review by the NRC
staff, and may increase the time and resources needed for the review.
Significant variations from the approach, or inclusion of additional
changes to the license, will result in staff rejection of the
submittal. Instead, licensees desiring significant variations and/or
additional changes should submit a LAR that does not claim to adopt
TSTF-431, Revision 2.
Public Notices
This notice requests comments from interested members of the public
within 30 days of the date of publication in the Federal Register.
After evaluating the comments received as a result of this notice, the
staff will either reconsider the proposed change or announce the
availability of the change in a subsequent notice (perhaps with some
changes to the SE, LAR, or the proposed NSHC determination as a result
of public comments). If the staff announces the availability of the
change, licensees wishing to adopt the change must submit an
application in accordance with applicable rules and other regulatory
requirements. For each application, the staff will publish a notice of
consideration of issuance of amendment to facility operating licenses,
a proposed NSHC determination, and a notice of opportunity for a
hearing. The staff will also publish a notice of issuance of an
amendment to operating license to announce the modification of end-
state requirements for required actions in plant technical
specifications.
Proposed Model Plant Specific Safety Evaluation for Technical
Specification Task Force (TSTF) Change TSTF-431, Revision 2, Change in
Technical Specifications End-States (BAW-2441), a Consolidated Line
Item Improvement
U.S. NUCLEAR REGULATORY COMMISSION SAFETY EVALUATION BY THE OFFICE OF
NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. [------] TO
FACILITY OPERATING LICENSE NFP-[------] [UTILITY NAME] [PLANT NAME],
[UNIT ------] DOCKET NO. -[------]
1.0 Introduction
By letter dated ------------, 20----, [Utility Name] (the licensee)
proposed changes to the technical specifications (TS) for [plant name].
The requested changes are the adoption of TSTF-431, Revision 2, to the
B&W Reactor Standard Technical Specifications (STS) (NUREG-1430), which
was proposed by the Technical Specifications Task Force (TSTF) on July
13, 2007, on behalf of the industry. TSTF-431, Revision 2, incorporates
the B&W Owners Group (B&WOG) approved Topical Report BAW-2441, Revision
2, ``Risk Informed Justification for LCO End-State Changes,'' September
2006, (Reference 1), into the B&W STS (Note: The changes are made with
respect to Revision 3 of the STS NUREGs).
TSTF-431, Revision 2, is one of the industry's initiatives
developed under the Risk Management Technical Specifications (RMTS)
program. These initiatives are intended to maintain or improve safety
through the incorporation of risk assessment and management techniques
in TS, while reducing unnecessary burden and making TS requirements
consistent with the Commission's other risk-informed regulatory
requirements, in particular the maintenance rule.
The Code of Federal Regulations, 10 CFR 50.36, ``Technical
Specifications,'' states: ``When a limiting condition for operation of
a nuclear reactor is not met, the licensee shall shut down the reactor
or follow the remedial action permitted by the technical specification
until the condition can be met.'' The STS and many plant TS provide a
completion time (CT) for the plant to meet the limiting condition for
operation (LCO). If the LCO or the remedial action cannot be met, then
the reactor is required to be shut down. When the STS and individual
plant technical specifications were written, the shutdown condition or
end-state specified was usually cold shutdown.
Topical Report BAW-2441, Revision 2, provides the technical basis
to change certain required end-states when the TS Actions for remaining
in power operation cannot be met within the CTs. Most of the requested
TS changes permit an end-state of hot shutdown (Mode 4), if risk is
assessed and managed, rather than an end-state of cold shutdown (Mode
5) contained in the current TS. The request was limited to those end-
states where: (1) Entry into the shutdown mode is for a short interval,
(2) entry is initiated by inoperability of a single train of equipment
or a restriction on a plant operational parameter, unless otherwise
stated in the applicable TS, and (3) the primary purpose is to correct
the initiating condition and return to power operation as soon as is
practical.
The STS for B&W plants defines six operational modes. In general,
they are:
Mode 1--Power Operation: Keff >= 0.99 and power
>5% RTP.
Mode 2--Startup: Keff >= 0.99 and power <= 5%
RTP.
Mode 3--Hot Standby: Keff < 0.99 and Tav
>= [330][deg]F.
Mode 4--Hot Shutdown: Keff < 0.99 and
[330][deg]F >= Tav >= [200][deg]F.
Mode 5--Cold Shutdown: Keff < 0.99 and Tav
<= [200][deg]F.
[[Page 65617]]
Mode 6--Refueling: One or more reactor vessel head closure
bolts are less than fully tensioned.
TSTF-431, Revision 2, generally allows a Mode 4 end-state rather
than a Mode 5end-state for selected initiating conditions in order to
perform short-duration repairs which necessitate exiting the original
Mode of operation. The affected TS are:
3.3.5 Engineered Safety Feature Actuation System (ESFAS)
Instrumentation.
3.3.6 ESFAS Manual Initiation.
3.4.6 Reactor Coolant System (RCS) Loops--MODE 4.
3.4.15 RCS Leakage Detection Instrumentation.
3.5.4 Borated Water Storage Tank (BWST).
3.6.2 Containment Air Locks.
3.6.3 Containment Isolation Valves.
3.6.4 Containment Pressure.
3.6.5 Containment Air Temperature.
3.6.6 Containment Spray and Cooling Systems.
3.7.7 Component Cooling Water System.
3.7.8 Service Water System.
3.7.9 Ultimate Heat Sink.
3.7.10 Control Room Emergency Ventilation System (CREVS).
3.7.11 Control Room Emergency Air Temperature Control System
(CREATCS).
3.8.1 AC Sources--Operating.
3.8.4 DC Sources--Operating.
3.8.7 Inverters--Operating.
3.8.9 Distribution Systems--Operating.
2.0 Regulatory Evaluation
In 10 CFR 50.36, the Commission established its regulatory
requirements related to the content of TS. Pursuant to 10 CFR 50.36(c),
TS are required to include items in the following five specific
categories related to plant operation: (1) Safety limits, limiting
safety system settings, and limiting control settings; (2) limiting
conditions for operation (LCOs); (3) surveillance requirements (SRs);
(4) design features; and (5) administrative controls. The rule does not
specify the particular requirements to be included in a plant's TS.
As stated in 10 CFR 50.36(c)(2)(i), the ``Limiting conditions for
operation are the lowest functional capability or performance levels of
equipment required for safe operation of the facility. When a limiting
condition for operation of a nuclear reactor is not met, the licensee
shall shut down the reactor or follow any remedial action permitted by
the technical specifications * * * .''
BAW-2441-A, Revision 2, ``Risk-Informed Justification for LCO End-
State Changes,'' September 2006 (Reference 1), provides justification
for changes to the end-states of selected LCO from Mode 5, cold
shutdown, to Mode 4, hot shutdown, in order to (1) reduce risk
associated with unnecessary shutdown cooling (SDC) operations, and (2)
reduce plant unavailability associated with reduced plant downtime
caused by unnecessary cooldown to Mode 5 and subsequent reheat to Mode
3 or 4. Reference 1 provides both a qualitative assessment and a
quantitative analysis to confirm that Mode 4 is the preferred end-state
from a risk and operational perspective. The qualitative assessment
describes the risk associated with operation in Mode 4 compared to
operation in Mode 5, in order to justify that the end-state of Mode 4,
versus Mode 5, for the proposed LCO conditions invoked, is acceptable.
The qualitative assessment concludes that the risk advantages
associated with Mode 4 operation versus Mode 5 operation are that: More
initiating event mitigating resources are available; human error during
SDC initiation and subsequent operation cannot occur; SDC
vulnerabilities are avoided; and inadvertent RCS draining via SDC
system related misalignments cannot occur.
Most of today's TS and the design basis analyses were developed
based on the perception that putting a plant in cold shutdown would
result in the safest condition and that the design basis analyses would
bound credible shutdown accidents. In the late 1980s and early 1990s,
the NRC and licensees recognized that this perception was incorrect and
took corrective actions to improve shutdown operation. At the same
time, standard TS were developed and many licensees improved their TS.
Since enactment of a shutdown rule was expected, almost all TS changes
involving power operation, including a revised end-state requirement,
were postponed (see, e.g., the Final Policy Statement on TS
Improvements (Reference 2)). However, in the mid 1990s, the Commission
decided a shutdown rule was not necessary in light of industry
improvements.
Controlling shutdown risk encompasses control of conditions that
can cause potential initiating events and responses to those initiating
events that may occur. Initiating events are a function of equipment
malfunctions and human error. Responses to events are a function of
plant sensitivity, ongoing activities, human error, defense-in-depth,
and additional equipment malfunctions.
In practice, the risk during shutdown operations is often addressed
via voluntary actions and application of 10 CFR 50.65 (Reference 3),
the maintenance rule. Section 50.65(a)(4) states: ``Before performing
maintenance activities * * * the licensee shall assess and manage the
increase in risk that may result from the proposed maintenance
activities. The scope of the assessment may be limited to structures,
systems, and components that a risk-informed evaluation process has
shown to be significant to public health and safety.'' Regulatory Guide
(RG) 1.182 (Reference 4) provides guidance on implementing the
provisions of 10 CFR 50.65(a)(4) by endorsing the revised Section 11
(published separately) to NUMARC 93-01, Revision 2. That section was
subsequently incorporated into Revision 3 of NUMARC 93-01 (Reference
5). However, Revision 3 has not yet been formally endorsed by the NRC.
The changes in TSTF-431 are consistent with the rules, regulations
and associated regulatory guidance, as noted above.
3.0 Technical Evaluation
The changes proposed in TSTF-431, Revision 2, are consistent with
the changes proposed and justified in Topical Report BAW-2441, Revision
2, as approved by the associated NRC SE (Reference 6). The evaluation
included in Reference 6, as appropriate and applicable to the changes
of TSTF-431, Revision 2 (Reference 7), is reiterated herein.
In its application, the licensee shall commit to TSTF-IG-07-01,
Implementation Guidance for TSTF-431, Revision 1, ``Change in Technical
Specifications End-States (BAW-2441),'' (Reference 8), which addresses
a variety of issues. An overview of the generic evaluation and
associated risk assessment is provided below, along with a summary of
the associated TS changes justified by Reference 1.
3.1 Risk Assessment
The objective of the BAW-2441, Revision 2, (Reference 1) risk
assessment was to show that any risk increases associated with the
proposed changes in TS end-states are either negligible or negative
(i.e., a net decrease in risk).
BAW-2441, Revision 2, documents a risk-informed analysis of the
proposed TS change. Probabilistic Risk Assessment (PRA) results and
insights were used, in combination with results of deterministic
assessments, to identify and propose changes in ``end-states'' for B&W
plants. This is in accordance with guidance provided in RG 1.174
(Reference 9) and RG 1.177 (Reference 10). The three-tiered approach
documented in RG 1.177, ``An Approach for Plant-Specific, Risk-Informed
Decision Making: Technical Specifications,'' was followed. The first
tier of the three-tiered approach
[[Page 65618]]
includes the assessment of the risk impact of the proposed change for
comparison to acceptance guidelines consistent with the Commission's
Safety Goal Policy Statement, as documented in RG 1.174 ``An Approach
for Using Probabilistic Risk Assessment in Risk-Informed Decisions on
Plant-Specific Changes to the Licensing Basis.'' In addition, the first
tier aims at ensuring that there are no unacceptable temporary risk
increases during the implementation of the proposed TS change, such as
when equipment is taken out of service. The second tier addresses the
need to preclude potentially high-risk configurations which could
result if equipment is taken out of service concurrently with the
implementation of the proposed TS change. The third tier addresses the
application of a configuration risk management program (CRMP),
implemented to comply with 10 CFR 50.65(a)(4) of the Maintenance Rule,
for identifying risk-significant configurations resulting from
maintenance-related activities and taking appropriate compensatory
measures to avoid such configurations. Unless invoked, such as by this
or another TS application, 50.65(a)(4) is applicable to maintenance-
related activities and does not cover other operational activities
beyond the effect they may have on existing maintenance related risk.
The risk assessment approach of BAW-2441, Revision 2, was found
acceptable in the SE for the topical report. In addition, the analyses
show that the the three-tiered approach criteria for allowing TS
changes are met as follows:
Risk Impact of the Proposed Change (Tier 1). The risk
changes associated with the TS changes in TSTF-431, in terms of mean
yearly increases in core damage frequency (CDF) and large early release
frequency (LERF), are risk neutral or risk beneficial. In addition,
there are no significant temporary risk increases, as defined by RG
1.177 criteria, associated with the implementation of the TS end-state
changes.
Avoidance of Risk-Significant Configurations (Tier 2). The
performed risk analyses, which are based on single LCOs, show that
there are no high-risk configurations associated with the TS end-state
changes. The reliability of redundant trains is normally covered by a
single LCO. To provide assurance that risk-significant plant equipment
outage configurations will not occur when specific equipment is out of
service, as part of the implementation of TSTF-431, the licensee will
commit to follow Section 11 of NUMARC 93-01, Revision 3, and to include
guidance in appropriate plant procedures and/or administrative controls
to preclude high-risk plant configurations when the plant is at the
proposed end-state. The staff finds that such guidance is adequate for
preventing risk-significant plant configurations.
Configuration Risk Management (Tier 3). The licensee shall
have a program, the CRMP, in place to comply with 10 CFR 50.65(a)(4) to
assess and manage the risk from proposed maintenance activities. This
program can be used to support a licensee decision in selecting the
appropriate actions to control risk for most cases in which a risk-
informed TS is entered. When multiple LCOs occur, which affect trains
in several systems, the plant's risk-informed CRMP, implemented in
response to the Maintenance Rule 10 CFR 50.65(a)(4), shall ensure that
high-risk configurations are avoided. In addition, to the extent that
the plant PRA is utilized in the CRMP, the plant PRA quality will be
assessed in accordance with NRC Regulatory Issue Summary 2007-06,
``Regulatory Guide 1.200 Implementation,'' (Reference 11).
The generic risk impact of the proposed end-state mode change was
evaluated subject to the following assumptions:
1. The entry into the proposed end-state is initiated by the
inoperability of a single train of equipment or a restriction on a
plant operational parameter, unless otherwise stated in the applicable
technical specification.
2. The primary purpose of entering the end-state is to correct the
initiating condition and return to power as soon as practical.
3. Plant implementation guidance for the proposed end-state changes
is developed to ensure that insights and assumptions made in the risk
assessment are properly reflected in the plant-specific CRMP.
These assumptions are consistent with typical entries into Mode 4
for short duration repairs, which is the intended use of the TS end-
state changes.
The staff concludes that, in general, going to Mode 4 (hot
shutdown) instead of going to Mode 5 (cold shutdown) to carry out
equipment repairs does not have any adverse effect on plant risk.
3.2 Assessment of TS Changes
The changes proposed by the licensee and in TSTF-431, Revision 2,
are consistent with the changes proposed in topical report BAW-2441,
Revision 2, and approved by the NRC SE of August 25, 2006. [NOTE: Only
those changes proposed in TSTF-431, Revision 2, are addressed in this
SE. The SE and associated topical report address the entire fleet of
B&W plants, and the plants adopting TSTF-431, Revision 2, must confirm
the applicability of the changes to their plant.] Following are the
proposed changes, including a synopsis of the STS LCO, the change, and
a brief conclusion of acceptability.
3.2.1 TS 3.3.5 Engineering Safety Features Actuation System (ESFAS)
Instruments
ESFAS instruments initiate high pressure injection (HPI), low
pressure injection (LPI), containment spray and cooling, containment
isolation, and onsite standby power source start. ESFAS also provides a
signal to the Emergency Feedwater Isolation and Control (EFIC) System.
This signal initiates emergency feed water (EFW) when HPI is initiated.
All functions associated with these systems, structures and components
(SSCs) can be initiated via operator action. This may be accomplished
at the channel level or the individual component level.
LCO: Three channels of ESFAS instrumentation for the applicable
parameters shall be operable in each ESFAS train.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.3.5 Condition B, Required Action B.2.3
and addresses only the reactor building (RB) High Pressure and RB High-
High Pressure setpoints. Specifically, if two or more channels are
inoperable or one channel is inoperable and the required action is not
met, then the Mode 5 end-state is prescribed within 36 hours subsequent
to an initial cooldown to Mode 3 within 6 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2.3 of this LCO is being proposed to
be changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: When operating in Mode 4, the reactor
system thermal-hydraulic conditions are very different from those
associated with a design basis accident (DBA) (at-power). That is, the
energy in the RCS is only that associated with decay heat in the core
and the stored energy in the reactor coolant system (RCS) components
and RCS pressure is reduced (especially toward the lower end of Mode
4). This means that the likelihood of an initiating event (IE)
occurring, for which ESFAS would provide mitigating functions, is
greatly reduced when operating in Mode 4. Nonetheless, all
[[Page 65619]]
redundant functions initiated by ESFAS can be manually initiated to
mitigate transients that will proceed more slowly and with reduced
challenge to the reactor and containment systems than those associated
with at-power operations. Also, when operating toward the lower end of
Mode 4, with the steam generators (SGs) in operation and SDC not in
operation, risk is reduced; risk associated with shutdown cooling (SDC)
operation is avoided. When operating in Mode 4 there are more
mitigation systems (e.g., HPI and EFW/auxiliary feed water (AFW))
available to respond to IEs that could challenge RCS inventory or decay
heat removal, than when operating in Mode 5. These systems include the
HPI system and EFW/AFW systems. Based on the above analysis, the staff
finds that the above requested change is acceptable.
3.2.2 TS 3.3.6 ESFAS Manual Initiation
The ESFAS manual initiation capability allows the operator to
actuate ESFAS functions from the main control room in the absence of
any other initiation condition. Manually actuated functions include
HPI, LPI, containment spray and cooling, containment isolation, and
control room isolation. The ESFAS manual initiation ensures that the
control room operator can rapidly initiate Engineered Safety Features
(ESF) functions at any time. In the absence of manual ESFAS initiation
capability, the operator can initiate any and all ESF functions
individually at a lower level.
LCO: Two manual initiation channels of each one of the following
ESFAS functions shall be operable: HPI, LPI, RB Cooling, RB Spray, RB
Isolation, and Control Room Isolation.
Conditions Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.3.6 Condition B, Required Action B.2.
Specifically, if one or more ESFAS functions with one channel are
inoperable and the required action and associated completion time are
not met, then Mode 3 is prescribed within 6 hours and Mode 5 within 36
hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: When operating in Mode 4, the thermal-
hydraulic conditions are very different than those associated with a
DBA (at-power). That is, the energy in the RCS is only that associated
with decay heat in the core and the stored energy in the RCS components
and RCS pressure is reduced (especially toward the lower end of Mode
4). This means that the likelihood of an IE occurring, for which ESFAS
manual initiation would provide mitigating functions, is greatly
reduced when operating in Mode 4. Nonetheless, all redundant functions
initiated by ESFAS manual initiation can be manually initiated via
individual component controls. In this way, transients, that will
proceed more slowly and with reduced challenge to the reactor and
containment systems than those associated with at-power operations,
will be mitigated. Also, when operating toward the lower end of Mode 4,
with the SGs in operation and SDC not in operation, risk is reduced
(i.e., the risk associated with SDC avoided). When operating in Mode 4
there are more mitigation systems (e.g. HPI and EFW/AFW) available to
respond to IEs that could challenge RCS inventory or decay heat
removal, than when operating in Mode 5. These systems include the HPI
system and EFW/AFW systems. Based on the above assessment, the staff
finds that the above requested change is acceptable.
3.2.3 TS 3.4.6 RCS Loops--MODE 4
The purpose of this LCO is to provide forced flow from at least one
RCP or one decay heat removal (DHR) pump for core decay heat removal
and transport. This LCO allows the two loops that are required to be
operable to consist of any combination of RCS or DHR system loops. Any
one loop in operation provides enough flow to remove the decay heat
from the core. The second loop that is required to be operable provides
redundant paths for heat removal. An ancillary function of the RCS and/
or DHR loops is to provide mixing of boron in the RCS. When operating
in Mode 4 if both RCS loops and one DHR loop is inoperable, the
existing LCO requires cooldown to Mode 5. In this situation, SGs are
available for core heat removal and transport via natural circulation
(NC) in Mode 4 without a need for significant RCS heatup. Proceeding to
Mode 5 makes few if any additional systems available for decay heat
removal (assuming a failure of the remaining DHR/LPI system). The one
system that can be made available in Mode 5 to provide backup to the
DHR system is the Borated Water Storage Tank (BWST). It can provide
gravity draining to the RCS after cooldown to Mode 5 and subsequent RCS
drain down and removal of SG primary side manway covers. This would
require a considerable time delay, during which RC temperature would be
increasing.
LCO: Two loops consisting of any combination of RCS loops and DHR
loops shall be operable and one loop shall be in operation.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.4.6 Condition A, Required Action A.2.
Specifically, if one required loop is inoperable, then action is taken
immediately to restore a second loop to operable status. Further, if
the remaining operable loop is a DHR loop, then entry into Mode 5 is
required within 24 hours.
Proposed Modification for End-State Required Actions: It is
proposed that Required Action A.2 be deleted, thus allowing continued
operations in Mode 4.
Assessment and Finding: When operating in Mode 4, if both RCS loops
and one DHR loop are inoperable, the existing LCO requires cooldown to
Mode 5. In this situation, SGs are available for core heat removal and
transport via NC in Mode 4 without the need for significant RCS heatup.
Proceeding to Mode 5 makes few if any additional systems available for
decay heat removal (assuming a failure of the remaining DHR system).
The one system that can be made available in Mode 5 to provide backup
to the DHR system is the BWST. It can provide gravity draining to the
RCS after cooldown to Mode 5 and subsequent RCS drain down and removal
of SG primary side manway covers. This would require a considerable
time delay, during which RC temperature would be increasing. Given
these considerations and magnitude of feedwater systems available to
feed the SGs, continued use of SGs for this situation will adequately
cool the core while avoiding the additional risk associated with SDC.
RC boron concentration will have been adjusted prior to cooldown to
Mode 4 to provide 1% shutdown margin (SDM) at the target cooldown
temperature. Thus, boron concentration adjustments would not be
necessary; RC boron would be sufficiently mixed to an equilibrium
concentration by this time. When operating in Mode 4 there are more
mitigation systems available to respond to IEs that could challenge RCS
inventory or decay heat removal, than when operating in Mode 5. These
systems include the HPI system and EFW/AFW systems. Based upon the
above assessment, the staff finds that the above requested change is
acceptable.
3.2.4 TS 3.4.15 RCS Leakage Detection Instrumentation
One method of protecting against large RCS leakage derives from the
ability of instruments to rapidly detect
[[Page 65620]]
extremely small leaks. This LCO requires instruments of diverse
monitoring principles to be operable to provide a high degree of
confidence that extremely small leaks are detected in time to allow
actions to place the plant in a safe condition when RCS leakage
indicates possible RC pressure boundary (RCPB) degradation. The LCO
requirements are satisfied when monitors of diverse measurement means
are available.
LCO: The following RCS leakage detection instrumentation shall be
operable:
a. One containment sump monitor and
b. One containment atmosphere radioactivity monitor (gaseous or
particulate).
Conditions Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.4.15 Condition C, Required Action C.2.
Specifically, if either the sump monitor or containment atmosphere
radioactivity monitor are inoperable and cannot be restored to
operability within 30 days, then Mode 3 is prescribed within 6 hours
and Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action C.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: Due to reduced RCS pressures when operating
in Mode 4, especially toward the lower end of Mode 4, the likelihood of
occurrence of a LOCA is very small; LOCA IE frequencies are reduced
compared to at-power operation. Because of this and because the reactor
is shutdown with significant radionuclide decay having occurred, the
probability of occurrence of a LOCA is decreased while the consequence
of such an event is not increased. Additional instruments are available
to provide secondary indication of a LOCA, e.g., additional containment
radioactivity monitors, grab samples of containment atmosphere,
humidity, temperature and pressure. Plant risk is lower when operating
in Mode 4 (not on SDC) than when operating in Mode 5; risk associated
with SDC operation is avoided. When operating in Mode 4 (not on SDC)
there are more mitigation systems (e.g., HPI and EFW/AFW) available to
respond to lEs that could challenge RCS inventory or decay heat
removal, than when operating in Mode 5. Based upon the above
assessment, the staff finds that the above requested change is
acceptable.
3.2.5 TS 3.5.4 Borated Water Storage Tank (BWST)
The BWST supports the emergency core cooling system (ECCS) and the
RB spray (RBS) system by providing a source of borated water for ECCS
and containment spray pump operation. The BWST supplies two ECCS
trains, each by a separate, redundant supply header. Each header also
supplies one train of RBS . A normally open, motor operated isolation
valve is provided in each header to allow the operator to isolate the
BWST from the ECCS after the ECCS pump suction has been transferred to
the containment sump following depletion of the BWST during a LOCA. The
ECCS and RBS are provided with recirculation lines that ensure each
pump can maintain minimum flow requirements when operating at shutoff
head conditions. This LCO ensures that: the BWST contains sufficient
borated water to support the ECCS during the injection phase,
sufficient water volume exists in the containment sump to support
continued operation of the ECCS and containment spray pumps at the time
of transfer to the recirculation mode of cooling, and the reactor
remains subcritical following a LOCA. Insufficient water inventory in
the BWST could result in insufficient cooling capacity of the ECCS when
the transfer to the recirculation mode occurs. Improper boron
concentrations could result in a reduction of SDM or excessive boric
acid precipitation in the core following a LOCA, as well as excessive
caustic stress corrosion of mechanical components and systems inside
containment.
LCO: The BWST shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.5.4 Condition C, Required Action C.2.
Specifically, if boron concentration is not within limits for 8 hours,
then Mode 3 is prescribed within 6 hours and Mode 5 within 36 hours.
Proposed Modification: The end-state associated with Required
Action C.2, as it relates to the boron concentration requirement of
this LCO, is being proposed to be changed from Mode 5 within 36 hours
to Mode 4 within 12 hours. No change is being proposed for the water
temperature requirement of the LCO. The end-state associated with
existing C.2 is proposed to be changed as follows:
4. Split existing Condition A into two conditions (A and C) such
that boron concentration and water temperature are addressed
separately, i.e., Condition A would address boron concentration and
Condition C would address water temperature. In either case the
Required Action, i.e., A.1 and C.1, would be to restore the BWST to
operable status within 8 hours.
5. A new Condition B would address boron concentration not within
limits and the Required Action and associated Completion Time not met.
Required Action B.1 would be to be in Mode 3 within 6 hours and B.2
would be to be in Mode 4 within 12 hours.
6. Existing Condition B would be renamed Condition D and would
address BWST inoperable for reasons other than Conditions A or C with a
Required Action D.1 to restore the BWST to operable status within I
hour.
Existing Condition C would be renamed Condition E and would address
Required Action and associated Completion Time for Conditions other
than Condition C or D not met. It would have the Required Action to be
in Mode 3 within 6 hours and Mode 5 within 36 hours.
Assessment and Finding: The limit for minimum boron concentration
in the BWST was established to ensure that, following a DBA large break
loss of coolant accident (LBLOCA), with a minimum BWST level, the
reactor will remain shut down in the cold condition following mixing of
the BWST and RCS water volumes. LBLOCA accident analyses assume that
all control rods remain withdrawn from the core. When operating in Mode
4, the control rods will either be inserted or the regulating rod
groups will be inserted with one or more of the safety rod groups
cocked and armed for automatic RPS insertion. Hence, all rods will not
be out should an IE occur. Also, given the highly unlikely possibility
of a LBLOCA occurring, it can be assumed all control rods will be
inserted should an IE occur while in Mode 4. This provides for the
reactor shutdown margin to be very conservative, i.e., in excess of
approximately -9.0% [Delta]k/k. For these reasons, and the design basis
assumptions that (a) deviations in boron concentration will be
relatively slow and small and that (b) boric acid addition systems
would normally be available (can be powered by [onsite standby power
sources]), the staff finds that the above requested change is
acceptable.
3.2.6 TS 3.6.2 Containment Air Locks
Containment air locks form part of the containment pressure
boundary and provide a means for personnel access during all modes of
operation. As such, air lock integrity and leak tightness is essential
for maintaining the containment leakage rate within limits in the event
of a DBA. Each air lock is
[[Page 65621]]
fitted with redundant seals and doors as a design feature for
mitigating the DBA. When operating in Mode 4 the energy that can be
released to the RB is a fraction of that which would be released for a
DBA. Also, the redundant containment spray and cooling systems,
required to be operable in Mode 4 but not in Mode 5, will be available
to ensure that containment pressure remains low should a LOCA occur.
LCO: Two containment air locks shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.6.2 Condition D, Required Action D.2.
Specifically, if one or more containment air locks are inoperable for
reasons other than condition A or B, then restore the air lock to
operable within 24 hours or Mode 3 is prescribed within 6 hours and
Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action D.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: The energy that can be released to the RB
when operating in Mode 4 is only a fraction of that associated with a
DBA, thus RB pressure will be only slightly higher should a LOCA occur
when operating in Mode 4 as compared to operating in Mode 5. Required
Action C.2 requires at least one air lock door to be closed, which
combined with reduced RB pressure should result in small containment
air lock leakage. Also, significant radionuclide decay will have
occurred, i.e., due to plant shutdown. For these reasons, no increase
in large early release frequency (LERF) is expected. In the unlikely
event that at least one door cannot be closed, evaluation of the effect
on plant risk and implementation of any required compensatory measures
will be accomplished in accordance with 10 CFR 50.65, i.e., the
``Maintenance Rule.'' Plant risk is lower when operating in Mode 4 (not
on SDC) than when operating in Mode 5 because there are more mitigation
systems (e.g., HPI and EFW/AFW) available to respond to IEs that could
challenge RCS inventory or decay heat removal. Also, the likelihood of
occurrence of a LOCA is very remote, thus the probability of occurrence
of a LOCA is decreased while the consequence of such and event is not
increased, and the staff finds that the above requested change is
acceptable.
3.2.7 TS 3.6.3 Containment Isolation Valves (CIVs)
The CIVs form part of the containment pressure boundary and provide
a means for fluid penetrations not serving accident consequence
limiting systems to be provided with two isolation barriers that are
closed on an automatic isolation signal. Two barriers in series are
provided for each penetration so that no single credible failure or
malfunction of an active component can result in a loss of isolation or
leakage that exceeds limits assumed in the safety analyses. One of
these barriers may be a closed system. These barriers (typically CIVs)
make up the Containment Isolation System. Containment isolation occurs
upon receipt of a high containment pressure or diverse containment
isolation signal. The containment isolation signal closes automatic
containment isolation valves in fluid penetrations not required for
operation of ESF to prevent leakage of radioactive material. Upon
actuation of HPI, automatic containment valves also isolate systems not
required for containment or RCS heat removal. Other penetrations are
isolated by the use of valves in the closed position or blind flanges.
As a result, the CIVs (and blind flanges) help ensure that the
containment atmosphere will be isolated in the event of a release of
radioactive material to containment atmosphere from the RCS following a
DBA. Operability of the containment isolation valves (and blind
flanges) supports containment operability during accident conditions.
The operability requirements for containment isolation valves help
ensure that containment is isolated within the time limits assumed in
the safety analyses. Therefore, the operability requirements provide
assurance that the containment function assumed in the safety analyses
will be maintained. When operating in Mode 4, there is decreased
potential for challenges to the containment than assumed in the
licensing basis; thus, containment pressures associated with lEs that
transfer energy to the containment will be only slightly higher when
operating in Mode 4 versus operating in Mode 5. When operating in Mode
4, versus Mode 5, there are more systems available to mitigate
precursor events, e.g., loss of feedwater and LOCA, that could cause
potential challenges to containment; also, potential fission product
release is reduced due to radionuclide decay.
LCO: Each containment isolation valve shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.6.3 Condition E, Required Action E.2.
Specifically, if the required action and associated completion time
cannot be met for penetration flow paths with inoperable isolation
valves or RB purge valve leakage limits (Conditions A, B, C and
Required Actions A.1, A.2, B.1, C.1 and C.2), then Mode 3 is prescribed
within 6 hours and Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action E.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: When in Mode 4 (not on SDC) there are more
mitigation systems available to respond to IEs that could challenge RCS
inventory or decay heat removal, than when operating in Mode 5. The
redundant RBS and RB cooling systems will be available to ensure that
containment pressure remains low should a LOCA occur. Because the
energy that can be released to the RB when operating in Mode 4 is only
a fraction of that associated with a DBA, RB pressure will be only
slightly higher should a LOCA occur when operating in Mode 4 as
compared to when operating in Mode 5. For these reasons, containment
leakage associated with CIVs is small, and with the plant shutdown
significant radionuclide decay will have occurred, therefore no
increase in LERF is expected. Due to reduced RCS pressures when
operating in Mode 4, especially toward the lower end of Mode 4, the
likelihood of occurrence of a LOCA is very small, i.e., LOCA IE
frequencies are reduced compared to at-power operation. The probability
of occurrence of a LOCA is decreased while the consequence of such an
event is not increased. Thus, plant risk is lower when operating in
Mode 4 (not on SDC) than when operating in Mode 5; risk associated with
SDC operation is avoided. Therefore, the staff finds that the above
requested change is acceptable.
3.2.8 TS 3.6.4 Containment Pressure
The containment pressure is limited during normal operation to
preserve the initial conditions assumed in the accident analyses for a
LOCA or steam line break (SLB). The containment air pressure limit also
prevents the containment pressure from exceeding the containment design
negative pressure differential with respect to the outside atmosphere
in the event of inadvertent actuation of the containment spray system.
Maintaining containment pressure less than or equal to the LCO upper
pressure limit (in
[[Page 65622]]
conjunction with maintaining the containment temperature limit) ensures
that: in the event of a DBA, the resultant peak containment accident
pressure will remain below the containment design pressure; the
containment environmental qualification operating envelope is
maintained; and, the ability of containment to perform its design
function is ensured. The containment high pressure limit is an initial
condition used in the DBA analyses to establish the maximum peak
containment internal pressure. Because only a small percentage of the
energy assumed for the DBA could be released to the containment, this
limit is overly conservative during operations in Mode 4. The low
containment pressure limit is based on inadvertent full (both trains)
actuation of the RB spray system. Invoking any condition associated
with the LCOs being proposed for an end-state change cannot initiate
this event; however, should it occur, there is ample time for operator
response to mitigate it.
LCO: Containment pressure shall be >=[-2.0] PSIG and <= [+3.0]
PSIG.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.6.4 Condition B, Required Action B.2.
Specifically, if containment pressure exceeds the limit and cannot be
restored within one hour, then Mode 3 is prescribed within 6 hours and
Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: The redundant RBS and RB cooling systems
will be available to ensure that containment pressure remains low
should a LOCA occur. Because the energy that can be released to the RB
when operating in Mode 4 is only a fraction of that associated with a
DBA, RB pressure will be only slightly higher should a LOCA occur when
operating in Mode 4 as compared to when operating in Mode 5. In such a
situation, the margin to the RB design pressure will be large, i.e., on
the order of several tens of PSI. Also, the occurrence of a LOCA of any
kind during operation in Mode 4 is considered highly unlikely. Because
of this and the occurrence of significant radionuclide decay (i.e., the
plant has been shutdown), no increase in LERF is expected should the
LCO for high containment pressure be invoked while in Mode 4. This is
especially germane considering that operations personnel will commence
actions to restore RB pressure to within the limit immediately upon
notification that it has exceeded the limit. RB vacuum conditions will
not compromise containment integrity of large dry containment of either
pre-stressed or reinforced concrete designs. One plant has a steel
containment configuration fitted with a vacuum breaker to mitigate
vacuum conditions. The risk associated with Mode 4 operation and RB
pressure below the LCO low pressure limit coincident with inadvertent
RB spray actuation is considered to be so low as to be inconsequential
(a search of available data bases found no record of this situation
having occurred to date at any B&W design plants). Also, operations
personnel will commence actions to restore RB pressure to within the
limit on notification that it has exceeded the limit.
Plant risk is lower when operating in Mode 4 (not on SDC) than when
operating in Mode 5; risk associated with SDC operation is avoided.
Also, when operating in Mode 4 (not on SDC) there are more mitigation
systems (e.g., HPI and EFW/AFW) available to respond to an IE that
could challenge RCS inventory or decay heat removal, than when
operating in Mode 5. These considerations ultimately lead to reduced
challenges to the RB when operating in Mode 4 versus Mode 5, and
therefore the staff finds that the above requested change is
acceptable.
3.2.9 TS 3.6.5 Containment Air Temperature
The containment average air temperature is limited during normal
operation to preserve the initial conditions assumed in the accident
analyses for a LOCA or SLB. The containment average air temperature
limit is derived from the input conditions used in the containment
functional analyses and the containment structure external pressure
analysis. This LCO ensures that initial conditions assumed in the
analysis of a DBA are not violated during unit operations. The total
amount of energy to be removed from the RB Cooling system during post
accident conditions is dependent upon the energy released to the
containment due to the event as well as the initial containment
temperature and pressure. The higher the initial temperature, the
higher the resultant peak containment pressure and temperature.
Exceeding containment design pressure may result in leakage greater
than that assumed in the accident analysis. Operation with containment
temperature in excess of the LCO limit violates an initial condition
assumed in the accident analysis. The limit for containment average air
temperature ensures that operation is maintained within the assumptions
used in the DBA analysis for containment; LOCA results in the greatest
sustained increase in containment temperature. By maintaining
containment air temperature at less than the initial temperature
assumed in the LOCA analysis, the reactor building design condition
will not be exceeded. As a result, the ability of containment to
perform its design function is ensured.
LCO: Containment average air temperature shall be < [130][deg]F.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.6.5 Condition B, Required Action B.2.
Specifically, if containment air temperature exceeds the limit and
cannot be restored within 8 hours, then Mode 3 is prescribed within 6
hours and Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: The redundant RBS and RB cooling systems
will be available to ensure that containment temperature remains low
should a LOCA occur. Because the energy that can be released to the RB
when operating in Mode 4 is only a fraction of that associated with a
DBA, the attendant RB temperature (and associated pressure) rise will
be well below that associated with a DBA. Also, the occurrence of a
LOCA of any kind during operation in Mode 4 is considered highly
unlikely. For these reasons and because of the occurrence of
significant radionuclide decay (i.e., the plant has been shut down), no
increase in LERF is expected. Plant risk is lower when operating in
Mode 4 (not on SDC) than when operating in Mode 5; risk associated with
SDC operation is avoided. Also, when operating in Mode 4 (not on SDC)
there are more mitigation systems (e.g., HPI and EFV/AFW) available to
respond to an IE that could challenge RCS inventory or decay heat
removal, than when operating in Mode 5. These considerations ultimately
lead to reduced challenges to the RB when operating in Mode 4 versus
Mode 5. Therefore, the staff finds that the above requested change is
acceptable.
3.2.10 TS 3.6.6 Containment Spray and Cooling Systems
The containment spray and cooling systems provide containment
atmosphere cooling to limit post accident pressure and temperature in
containment to less than the design values. Reduction of containment
[[Page 65623]]
pressure and the iodine removal capability of the spray reduces the
release of fission product radioactivity from containment to the
environment, in the event of a DBA. When operating in Mode 4, the
release of stored energy to the RB can be only a small fraction of the
energy associated with a DBA. This, along with the fact there are
redundant trains of containment spray and cooling, assures this
engineered safety feature (ESF) will be supported during operation in
Mode 4. Also, the function associated with containment spray iodine
removal capability will be less challenged when operating in Mode 4 due
to radionuclide decay.
LCO: Two containment spray trains and two containment cooling
trains shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.6.6 Condition B, Required Action B.2
(containment spray system) and Condition F, Required Action F.2
(containment cooling system). Specifically: if one containment spray
train is inoperable and cannot be restored within 72 hours or within 10
days of discovery of failure to meet the LCO, then Mode 3 is prescribed
within 6 hours and Mode 5 within 84 hours; and, if two containment
cooling trains are inoperable and cannot be restored within 72 hours,
then Mode 3 is prescribed within 6 hours and Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2 of this LCO is being proposed to be
changed from Mode 5 within 84 hours to Mode 4 within 60 hours, and the
end-state associated with Required Action F.2 of this LCO is being
proposed to be changed from Mode 5 within 36 hours to Mode 4 within 12
hours.
Assessment and Finding: In Mode 4 the release of stored energy to
the RB would be only that associated with decay heat energy and energy
stored in the RCS components. That is, over 95% of the energy assumed
to be released to the RB during the DBA LOCA is associated with the
core thermal power resulting from 100% full power. Since the reactor is
already shut down, such a thermal release to the RB is not possible;
only a small fraction of this energy could be released. Occurrence of
the DBA, a 28 inch cold leg guillotine break at a RCP discharge, is
considered to be very unlikely to occur at any time, much less while
operating in Mode 4. Indeed, the occurrence of a LOCA of any kind
during operation in this Mode is considered highly unlikely. Due to the
redundancy of the containment spray and cooling systems, both their
functions are available to control and maintain RB pressure well below
the design limit; the function to remove radioactive iodine from the
containment atmosphere will also be available.
Because the energy that can be released to the RB when operating in
Mode 4 is only a fraction of that associated with a DBA, RB pressure
will be only slightly higher should a LOCA occur when operating in Mode
4 as compared to when operating in Mode 5. For these reasons
containment leakage is small and because significant radionuclide decay
will have occurred, (i.e., because the plant has been shut down), no
increase in LERF is expected.
Plant risk is lower when operating in Mode 4 (not on SDC) than when
operating in Mode 5; risk associated with SDC operation is avoided.
Also, when operating in Mode 4 (not on SDC) there are more mitigation
systems (e.g., HPI and EFW/AFW) available to respond to an IE that
could challenge RCS inventory or decay heat removal, than when
operating in Mode 5. These considerations ultimately lead to reduced
challenges to the containment spray and cooling systems when operating
in Mode 4 versus Mode 5. Therefore, the staff finds that the above
requested change is acceptable.
3.2.11 LCO 3.7.7 Component Cooling Water (CCW) System
This system provides cooling for ECCS equipment including EFW pumps
that function to mitigate loss of feedwater IEs, and containment
control equipment.
LCO: Two CCW trains shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.7.7 Condition B, Required Action B.2.
Specifically, if a CCW train becomes inoperable and cannot be restored
within 72 hours, then Mode 3 is prescribed within 6 hours and Mode 5
within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: In Mode 4 the stored energy of the reactor
system would be only that associated with reduced decay heat energy and
energy stored in the RCS components. Because of this, heat loads on the
CCW system will be greatly reduced from those associated with the DBA,
i.e., a LOCA. Also, occurrence of a design bases LOCA is considered to
be very unlikely to occur at anytime much less while operating in Mode
4. Indeed, the occurrence of a LOCA of any kind during operation in
this Mode is considered highly unlikely. Plant risk is lower when
operating in Mode 4 (not on SDC) than when operating in Mode 5; risk
associated with SDC operation is avoided. Also, when operating in Mode
4 (not on SDC) there are more mitigation systems (e.g., HPI and EFW/
AFW) available to respond to an IE that could challenge RCS inventory
or decay heat removal, than when operating in Mode 5. These
considerations ultimately lead to reduced challenges to the CCW system
when operating in Mode 4 versus Mode 5. Therefore, the staff finds that
the above requested change is acceptable.
3.2.12 TS 3.7.8 Service Water System (SWS)
This system provides cooling for equipment that supplies boron to
the RCS, i.e., HPI and emergency boration system.
LCO: Two SWS trains shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.7.8 Condition B, Required Action B.2.
Specifically, if an SWS train becomes inoperable and cannot be restored
within 72 hours, then Mode 3 is prescribed within 6 hours and Mode 5
within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: In Mode 4 the stored energy of the reactor
system would be only that associated with reduced decay heat energy and
energy stored in the RCS components. Because of this, heat loads on the
SWS will be greatly reduced from those associated with the DBA, i.e., a
LOCA. Also, occurrence of a design bases LOCA is considered to be very
unlikely to occur at anytime much less while operating in Mode 4.
Indeed, the occurrence of a LOCA of any kind during operation in this
Mode is considered highly unlikely. Plant risk is lower when operating
in Mode 4 (not on SDC) than when operating in Mode 5; risk associated
with SDC operation is avoided. Also, when operating in Mode 4 (not on
SDC) there are more mitigation systems (e.g., HPI and EFW/AFW)
available to respond to an IE that could challenge RCS inventory or
decay heat removal, than when operating in Mode 5. These considerations
ultimately lead to reduced challenges to the SWS when operating in Mode
4 versus Mode 5, and
[[Page 65624]]
therefore, the staff finds that the above requested change is
acceptable.
3.2.13 TS 3.7.9 Ultimate Heat Sink (UHS)
The UHS provides a heat sink for process and operating heat from
safety related components during a transient or accident as well as
during normal operation. The UHS has been defined as that complex of
water sources, including necessary retaining structures (e.g., a pond
with its dam, or a river with its dam), and the canals or conduits
connecting the sources with, but not including, the cooling water
system intake structures. The two principal functions of the UHS are
the dissipation of residual heat after a reactor shutdown, and
dissipation of residual heat after an accident. The UHS is the sink for
heat removal from the reactor core following all accidents and
anticipated occurrences (AOs) in which the unit is cooled down and
placed on DHR. Its maximum post accident heat load occurs approximately
20 minutes after a design basis LOCA. Near this time, the unit switches
from injection to recirculation and the containment cooling systems are
required to remove the core decay heat.
LCO: The UHS shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.7.9 Condition C, Required Action C.2.
Specifically, if the UHS complex becomes inoperable due to condition A
and cannot be restored within 72 hours, then Mode 3 is prescribed
within 6 hours and Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action C.2, as it relates to Condition A only,
of this LCO is being proposed to be changed from Mode 5 within 36 hours
to Mode 4 within 12 hours. It is proposed that a new Action B be added,
that addresses Condition A only. The Required Action of the new
Condition B if Required Action and associated Completion Time of
Condition A is not met is proposed to be Mode 3 within 6 hours and Mode
4 within 12 hours. Existing Condition B would be re-lettered to
Condition C and existing Condition C would be re-lettered to Condition
D. The first Boolean statement of Condition D would refer only to
Condition C.
Assessment and Finding: In Mode 4 the stored energy of the reactor
system would be only that associated with reduced decay heat energy and
energy stored in the RCS components. Because of this, heat loads on the
UHS will be greatly reduced from those associated with the DBA, i.e., a
LOCA. Also, occurrence of a design basis LOCA is considered to be very
unlikely to occur at anytime much less while operating in Mode 4. The
occurrence of a LOCA of any kind during operation in this Mode is
considered highly unlikely. Plant risk is lower when operating in Mode
4 (not on SDC) than when operating in Mode 5; risk associated with SDC
operation is avoided. Also, when operating in Mode 4 (not on SDC) there
are more mitigation systems (e.g., HPI and EFW/AFW) available to
respond to an IE that could challenge RCS inventory or decay heat
removal, than when operating in Mode 5. These considerations ultimately
lead to reduced challenges to the UHS when operating in Mode 4 versus
Mode 5, and therefore the staff finds that the above requested change
is acceptable.
3.2.14 TS 3.7.10 Control Room Emergency Ventilation System (CREVS)
The CREVS provides a protected environment from which operators can
control the unit following an uncontrolled release of radioactivity,
[chemicals, or toxic gas]. The CREVS consists of two independent,
redundant, fan filter assemblies. Upon receipt of the activating
signal(s), the normal control room ventilation system is automatically
shut down and the CREVS can be manually started. The CREVS is designed
to maintain the control room for 30 days of continuous occupancy after
a DBA without exceeding a 5 rem whole body dose or its equivalent to
any part of the body.
LCO: Two CREVS trains shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.7.10 Condition C, Required Action C.2.
Specifically, if one train of CREVS becomes inoperable and cannot be
restored within 7 days or two CREVS trains become inoperable (due to
inoperable control room boundary) and cannot be restored within 24
hours, then Mode 3 is prescribed within 6 hours and Mode 5 within 36
hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action C.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: This system would be required in the event
the main control room (MCR) was isolated. Such an isolation would be
directly due to an uncontrolled release of radioactivity, [chemicals,
or toxic gas]. Uncontrolled release of radioactivity would be
associated with a LOCA. A LOCA is considered highly unlikely to occur
during Mode 4 operations. This is especially true of operations toward
the lower end of Mode 4 while operating on SGs (SDC not in operation).
Regardless of the CREVS status, the risks associated with Mode 4 are
lower than the Mode 5 operating state. Relative to the uncontrolled
release of [chemicals, or toxic gas], this situation is the same as
when operating in Mode 5, i.e., frequencies for occurrence of these IEs
are the same in Mode 5 as Mode 4. Plant risk is lower when operating in
Mode 4 (not on SDC) than when operating in Mode 5; risk associated with
SDC operation is avoided. Also, when operating in Mode 4 there are more
mitigation systems available to respond to IEs that could challenge RCS
inventory or decay heat removal, than when operating in Mode 5. These
systems include the HPI system and EFW/AFW systems. These
considerations should ultimately lead to reduced challenges to CREVS
when operating in Mode 4 versus Mode 5, and therefore, the staff finds
that the above requested change is acceptable.
3.2.15 TS 3.7.11 Control Room Emergency Air Temperature Control System
(CREATCS)
The CREATCS provides temperature control for the control room
following isolation of the control room. The CREATCS consists of two
independent and redundant trains that provide cooling of recirculated
control room air. A cooling coil and a water cooled condensing unit are
provided for each system to provide suitable temperature conditions in
the control room for operating personnel and safety related control
equipment. Ductwork, valves or dampers, and instrumentation also form
part of the system. Two redundant air cooled condensing units are
provided as a backup to the water cooled condensing unit. Both the
water cooled and air cooled condensing units must be operable for the
CREATCS to be operable. During emergency operation, the CREATCS
maintains the temperature between 70[deg]F and 85[deg]F. The CREATCS is
a subsystem of CREVS providing air temperature control for the control
room.
LCO: Two CREATCS trains shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.7.11 Condition B, Required Action B.2.
Specifically, if a CREATCS train becomes inoperable and cannot be
restored within 30 days, then Mode 3 is prescribed within 6 hours and
Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action B.2 of this LCO is being proposed to be
[[Page 65625]]
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: This system is a subsystem of CREVS and
would be required in the event the MCR was isolated. Such an isolation
would be directly due to an uncontrolled release of radioactivity,
[chemicals, or toxic gas]. Uncontrolled release of radioactivity would
be associated with a LOCA. A LOCA is considered highly unlikely to
occur during Mode 4 operations. This is especially true of operations
toward the lower end of Mode 4 while operating on SGs (SDC not in
operation). Relative to the uncontrolled release of [chemicals, or
toxic gas], this situation is the same as when operating in Mode 5,
i.e., frequencies for occurrence of these IEs are the same in Mode 5 as
in Mode 4. When operating in Mode 4 there are more mitigation systems
available to respond to IEs that could challenge RCS inventory or decay
heat removal, than when operating in Mode 5. These systems include the
HPI system and EFW/AFW systems. This should ultimately lead to reduced
challenges to CREACTS when operating in Mode 4 versus Mode 5. Plant
risk is lower when operating in Mode 4 (not on SDC) than when operating
in Mode 5; risk associated with SDC operation is avoided. Therefore,
the staff finds that the above requested change is acceptable.
3.2.16 TS 3.8.1 AC Source--Operating
The unit Class IE AC Electrical Power Distribution System
alternating current (AC) sources consist of the offsite power sources
(preferred power sources, normal and alternate(s)) and the [onsite
standby power sources]. The AC electrical power system provides
independence and redundancy to ensure an available source of power to
the ESF systems. The onsite Class 1E AC Distribution System is divided
into redundant load groups (trains) so that the loss of any one group
does not prevent the minimum safety functions from being performed.
Each train has connections to two preferred offsite power sources and a
single [onsite standby power source]. Offsite power is supplied to the
unit switchyard(s) from the transmission network by [two] transmission
lines. From the switchyard(s), two electrically and physically
separated circuits provide AC power, through [step down station
auxiliary transformers] to the 4.16 kV ESF buses.
The initial conditions of DBA and transient analyses in the safety
analysis report (SAR) assume ESF systems are operable. The AC
electrical power sources are designed to provide sufficient capacity,
capability, redundancy, and reliability to ensure the availability of
necessary power to ESF systems so that the fuel, RCS, and containment
design limits are not exceeded. During operations in Mode 4 there is
always a need to assure power is available to SSCs that support the
critical safety functions. To this end, AC power sources are assured
during occurrence of a loss of offsite power (LOOP) by operation of one
of two redundant [onsite standby power sources]. This situation is no
different than when operating in Mode 4 or 5.
LCO: The following AC electrical power sources shall be operable:
a. Two qualified circuits between the offsite transmission network
and the onsite Class 1E AC Electrical Power Distribution System,
b. Two diesel generators (DG) each capable of supplying one train
of the onsite Class 1E AC Electrical Power Distribution System, and
[c. Automatic load sequencers for Train A and Train B.]
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.8.1 Condition G, Required Action G.2.
Specifically, if the required actions and associated completion times
of Condition A, B, C, D, E or F cannot be met, then Mode 3 is
prescribed within 12 hours and Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action G.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: The operability requirements of the AC
electrical power sources is predicated on initial assumptions of the
accident analyses most notably design basis LOCAs. A design basis LOCA
is considered highly unlikely to occur during at-power operations, much
less during Mode 4; indeed, the occurrence of a LOCA of any kind during
operation in Mode 4 is considered highly unlikely. This is especially
true of operations toward the lower end of Mode 4 while operating on
SGs (SDC not in operation). Plant risk is lower when operating in Mode
4 (not on SDC) than when operating in Mode 5; risk associated with SDC
operation is avoided. Also, when operating in Mode 4 there are more
mitigation systems (e.g., HPI and EFW/AFWV) available to respond to IEs
that could challenge RCS inventory or decay heat removal, than when
operating in Mode 5. These systems include the HPI system and EFWV/AFW
systems. This consideration is particularly germane as it relates to
loss of AC power sources because with the SGs operating in Mode 4,
turbine driven EFW pumps (TDEFWPs) are immediately available with SG
pressure of [50 PSIG (-2981F RCS temperature)]. These considerations
ultimately lead to reduced challenges to CDF and LERF when operating in
Mode 4 versus operations in Mode 5. The redundant nature of the AC
power sources, including [onsite standby power sources], provides for
availability of AC power even if one source becomes inoperable.
Therefore, the staff finds that the above requested change is
acceptable.
3.2.17 TS 3.8.4 DC Sources--Operating
The station direct current (DC) electrical power system provides
the alternating current (AC) emergency power system with control power.
It also provides both motive and control power to selected safety
related equipment and preferred AC vital bus power (via inverters). The
DC electrical power system is designed to have sufficient independence,
redundancy, and testability to perform its safety functions, assuming a
single failure. The [125/250] voltage DC (VDC) electrical power system
consists of two independent and redundant safety related Class IE DC
electrical power subsystems ([Train A and Train B]). The need for DC
power to support the ESFs is assured during a LOOP by operation of one
redundant train of station DC power as backed from the [onsite standby
power sources] via the associated battery charger. This situation is no
different for Mode 4 or Mode 5.
LCO: The Train A and Train B DC electrical subsystems shall be
operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.8.4 Condition D, Required Action D.2.
Specifically, if one DC electrical power subsystem becomes inoperable
and cannot be restored within 2 hours, then Mode 3 is prescribed within
6 hours and Mode 5 within 36 hours.
Proposed Modification: The end-state associated with Required
Action D.2 of this LCO is being proposed to be changed from Mode 5
within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: The operability requirements of the DC
electrical power sources is predicated on initial assumptions of the
accident analyses most notably design basis LOCAs. A design basis LOCA
is
[[Page 65626]]
considered highly unlikely to occur during at-power operations, much
less during Mode 4; indeed, the occurrence of a LOCA of any kind during
operation in Mode 4 is considered highly unlikely. This is especially
true of operations toward the lower end of Mode 4 while operating on
SGs (SDC not in operation). Plant risk is lower when operating in Mode
4 (not on SDC) than when operating in Mode 5; risk associated with SDC
operation is avoided. Also, when operating in Mode 4 there are more
mitigation systems available to respond to IEs that could challenge
decay heat removal, than when operating in Mode 5. These systems
include the HPI and EFW/AFW systems. This consideration is particularly
germane as it relates to loss of DC power sources (control and circuit
breaker closure power for plant equipment) because with the SGs
operating in Mode 4, TDEFWPs are immediately available with SG pressure
of [50 PSIG (-298[deg]F RCS temperature)]. These considerations should
ultimately lead to reduced challenges to CDF and LERF when operating in
Mode 4 versus operations in Mode 5. The redundant nature of the DC
power sources, provides for availability of DC power even if one source
becomes in inoperable. Therefore, the staff finds that the above
requested change is acceptable.
3.2.18 TS 3.8.9 Distribution Systems--Operating
The onsite Class IE AC, DC, and AC vital bus electrical power
distribution systems are divided by train into [two] redundant and
independent AC, DC, and AC vital bus electrical power distribution
subsystems. The required power distribution systems ensure the
availability of AC, DC, and AC vital bus electrical power for the
systems required to shut down the reactor and maintain it in a safe
condition after an AOO or a postulated DBA. Maintaining the train A and
B, AC, DC, and AC vital bus electrical power distribution subsystems
operable ensures that the redundancy incorporated into the design of
ESF is not defeated. Therefore, a single failure within any system or
within the electrical power distribution subsystems will not prevent
safe shutdown of the reactor. Providing for reactor shutdown is not a
concern while operating in Mode 4. However, maintaining safe plant
conditions is always a concern and requires that at least one redundant
electrical distribution system be operable. This is assured by the
redundant electrical distribution system design and the ability to
power one of these systems via batteries backed by [onsite standby
power sources] for DC distribution and AC vital buses, and [onsite
standby power sources] for AC distribution. There is no difference in
this situation whether the plant is operating in Mode 4 or 5.
LCO: The Train A and Train B AC, DC and AC vital bus electrical
power distribution subsystems shall be operable.
Condition Requiring Entry into End-State: This proposed end-state
change is associated with LCO 3.8.9 Condition D, Required Action D.2.
Specifically, if the required actions and associated completion times
of Condition A, B or C cannot be met, then Mode 3 is prescribed within
6 hours and Mode 5 within 36 hours.
Proposed Modification for End-State Required Actions: The end-state
associated with Required Action D.2 of this LCO is being proposed to be
changed from Mode 5 within 36 hours to Mode 4 within 12 hours.
Assessment and Finding: The operability requirements of the AC, DC,
and AC vital bus electrical power distribution systems are predicated
on providing the necessary power to ESF systems so that the fuel, RCS,
and containment design limits are not exceeded in the event of a design
basis LOCA. A design basis LOCA is considered highly unlikely to occur
during at-power operations, much less during Mode 4; indeed, the
occurrence of a LOCA of any kind during operation in Mode 4 is
considered highly unlikely. This is especially true of operations at
the lower end of Mode 4 while operating on SGs (SDC not in operation).
Plant risk is lower when operating in Mode 4 (not on SDC) than when
operating in Mode 5; risk associated with SDC operation is avoided.
Also, when operating in Mode 4 there are more mitigation systems
available to respond to IEs that could challenge RCS inventory or decay
heat removal, than when operating in Mode 5. These systems include the
HPI system and EFW/AFW systems. This consideration is particularly
germane as it relates to loss of electrical power distribution systems
because with the SGs operating in Mode 4, TDEFWPs are immediately
available with SG pressure of [50 PSIG (-2980F RCS temperature)]. This
consideration should ultimately lead to reduced challenges to CDF and
LERF when operating in Mode 4 versus operations in Mode 5. The
redundant nature of the AC, DC, and AC vital bus electrical power
distribution systems, including [onsite standby power sources],
provides for availability of electrical power even if one power
distribution system becomes inoperable. Therefore, the staff finds that
the above requested change is acceptable.
4.0 State Consultation
In accordance with the Commission's regulations, the [--------]
State official was notified of the proposed issuance of the amendment.
The State official had [(1) no comments or (2) the following comments--
with subsequent disposition by the staff].
5.0 Environmental Consideration
The amendment changes requirements with respect to the installation
or use of a facility component located within the restricted area as
defined in 10 CFR Part 20. The NRC staff has determined that the
amendment involves no significant increase in the amounts and no
significant change in the types of any effluents that may be released
offsite, and that there is no significant increase in individual or
cumulative occupational radiation exposure.20. [The NRC staff has
determined that the amendment involves a change in surety, insurance,
and/or indemnity requirements, or recordkeeping, reporting, or
administrative procedures or requirements.] The Commission has
previously issued a proposed finding that the amendment involves no
significant hazards considerations, and there has been no public
comment on the finding [FR ]. Accordingly, the amendments meet the
eligibility criteria for categorical exclusion set forth in 10 CFR
51.22(c)(9) [and (c)(10)]. Pursuant to 10 CFR 51.22(b), no
environmental impact statement or environmental assessment need be
prepared in connection with the issuance of the amendment.
6.0 Conclusion
The Commission has concluded, on the basis of the considerations
discussed above, that (1) there is reasonable assurance that the health
and safety of the public will not be endangered by operation in the
proposed manner, (2) such activities will be conducted in compliance
with the Commission's regulations, and (3) the issuance of the
amendments will not be inimical to the common defense and security or
to the health and safety of the public.
7.0 References
1. BAW-2441-A, Revision 2, ``Risk-Informed Justification for LCO
End-State Changes,'' September 2006.
2. Federal Register, Vol. 58, No. 139, p. 39136, ``Final Policy
Statement on Technical Specifications Improvements for Nuclear Power
Plants,'' July 22, 1993.
3. 10 CFR 50.65, Requirements for
[[Page 65627]]
``Monitoring the Effectiveness of Maintenance at Nuclear Power
Plants.''
4. Regulatory Guide 1.182, ``Assessing and Managing Risk Before
Maintenance Activities at Nuclear Power Plants,'' May 2000.
(ML003699426).
5. NUMARC 93-01, ``Industry Guideline for Monitoring the
Effectiveness of Maintenance at Nuclear Power Plants,'' Nuclear
Management and Resource Council, Revision 3, July 2000.
6. NRC Safety Evaluation for Topical Report BAW-2441, Revision 2,
August 25, 2006. (ML062130286).
7. TSTF-431, Revision 2, ``Change in Technical Specifications End-
States, BAW-2441-A.''
8. TSTF-IG-07-01, Implementation Guidance for TSTF-431, Revision 1,
``Change in Technical Specifications End-States, BAW-2441-A,'' April
2007.
9. Regulatory Guide 1.174, ``An Approach for Using Probabilistic
Risk Assessment in Risk-Informed Decision Making on Plant Specific
Changes to the Licensing Basis,'' USNRC, August 1998. (ML003740133).
10. Regulatory Guide 1.177, ``An Approach for Pant Specific Risk-
Informed Decision Making: Technical Specifications,'' USNRC, August
1998. (ML003740176).
11. Regulatory Issue Summary 2007-06, ``Regulatory Guide 1.200
Implementation,'' USNRC, March 22, 2007.
The Following Example of an Application Was Prepared by the NRC Staff
To Facilitate Use of the Consolidated Line Item Improvement Process
(CLIIP). The Model Provides the Expected Level of Detail and Content
for an Application To Change Technical Specifications End-States for
B&W Plants Using CLIIP. Licensees Remain Responsible for Ensuring That
Their Actual Application Fulfills Their Administrative Requirements as
Well as Nuclear Regulatory Commission Regulations
U.S. Nuclear Regulatory Commission, Document Control Desk,
Washington, D.C. 20555.
SUBJECT:
PLANT NAME
DOCKET NO. 50--APPLICATION FOR ADOPTING TECHNICAL SPECIFICATION
CHANGE TO REQUIRED ACTION End-States FOR B&W PLANTS USING THE
CONSOLIDATED LINE ITEM IMPROVEMENT PROCESS
Gentleman:
In accordance with th provisions of 10 CFR 50.90 [LICENSEE] is
submitting a request for an amendment to the technical
specifications (TS) for [PLANT NAME, UNIT NOS.].
The proposed amendment would modify TS requirements for end-
states associated with implementation of BAW-2441-A, Revision 2,
``Risk-Informed Justification for LCO End-State Changes.''
Attachment 1 provides a description of the proposed change, the
requested confirmation of applicability, and plant-specific
verifications. Attachment 2 provides the existing TS pages marked up
to show the proposed change. Attachment 3 provides revised (clean)
TS pages. Attachment 4 provides a summary of the regulatory
commitments made in this submittal.
[LICENSEE] requests approval of the proposed License Amendment
by [DATE], with the amendment being implemented [BY DATE OR WITHIN X
DAYS].
In accordance with 10 CFR 50.91, a copy of this application,
with attachments, is being provided to the designated [STATE]
Official.
I declare under penalty of perjury under the laws of the United
Stats of America that I am authorized by [LICENSEE] to make this
request and that the foregoing is true and correct. (Note that
request may be notarized in lieu of using this oath or affirmation
statement).
If you should have any questions regarding this submittal,
please contact [NAME, TELEPHONE NUMBER]
Sincerely,
[Name, Title]
Attachments:
1. Description and Assessment
2. Proposed Technical Specification Changes
3. Revised Technical Specification Pages
4. Regulatory Commitments
5. Proposed Technical Specification Bases Changes
cc:
NRC Project Manager
NRC Regional Office
NRC Resident Inspector
State Contact
Attachment 1--Description and Assessment
1.0 Description
The proposed amendment would modify TS end-state requirements
associated with implementation of BAW-2441-A, Revision 2, ``Risk-
Informed Justification for LCO End-State Changes.'' Current technical
specification action requirements frequently require that the unit be
brought to cold shutdown when the TS limiting condition for operation
for a system has not been met. Depending on the system, and the
affected safety function, the requirement to go to cold shutdown may
not represent the most risk effective course of action. In accordance
with the qualitative risk analysis in BAW-2441-A, Revision 2, and the
license amendment request, that provide a basis for changing the TS
shutdown action requirement, where appropriate the shutdown end-state
is changed from cold shutdown to hot shutdown.
The changes are consistent with Nuclear Regulatory Commission (NRC)
approved Industry/Technical Specification Task Force (TSTF) STS change
TSTF-431, Revision 2. The Federal Register notice published on [DATE]
announced the availability of this TS improvement through the
consolidated line item improvement process (CLIIP).
2.0 Assessment
2.1 Applicability of Published Safety Evaluation
[LICENSEE] has reviewed the safety evaluation dated [DATE] as part
of the CLIIP. This review included a review of the NRC staff's
evaluation, as well as the supporting information provided to support
TSTF-431, Revision 2. [LICENSEE] has concluded that the justifications
presented in the TSTF proposal and the safety evaluation prepared by
the NRC staff are applicable to [PLANT, UNIT NOS.] and the
justifications apply to this amendment for the incorporation of the
changes to the [PLANT] TS.
2.2 Optional Changes and Variations
[LICENSEE] is not proposing any variations or deviations from the
TS changes described in TSTF-431, Revision 2, and the NRC staff's model
safety evaluation dated [DATE].
3.0 Regulatory Analysis
3.1 No Significant Hazards Consideration Determination
[LICENSEE] has reviewed the proposed no significant hazards
consideration determination (NSHCD) published in the Federal Register
as part of the CLIIP. [LICENSEE] has concluded that the proposed NSHCD
presented in the Federal Register notice is applicable to [PLANT] and
is [attached, or incorporated herein/following] satisfying the
requirements of 10 CFR 50.91(a).
3.2 Verification and Commitments
As discussed in the notice of availability published in the Federal
Register on [DATE] for this TS improvement, the [LICENSEE] verifies the
applicability of TSTF-431, Revision 2, to [PLANT], and commits to
following the guidance set forth in TSTF-IG-07-01, Implementation
Guidance for TSTF-431, Revision 1, Change in Technical Specifications
End-States (BAW-2441).''
The proposed TSTF-431, revision 2, change revises selected required
action end-states for B&W STS (NUREG-1430) by allowing plants to go to
hot shutdown versus cold shutdown for short durations to effect
equipment repairs, after the performance of a plant configuration risk
assessment. This application implements TS changes approved in BAW-
2441-A, Revision 2,
[[Page 65628]]
``Risk-Informed Justification for LCO End-State Changes.''
4.0 Environmental Evaluation
[LICENSEE] has reviewed the environmental evaluation included in
the model safety evaluation dated [DATE] as part of the CLIIP.
[LICENSEE] has concluded that the staff's findings presented in that
evaluation are applicable to [PLANT] and the evaluation is [attached,
or incorporated herein/following] for this application.
ATTACHMENT 2--Proposed Technical Specification Changes (Mark-Up)
ATTACHMENT 3--Proposed Technical Specification Pages
ATTACHMENT 4--List of Regulatory Commitments
The following table identifies those actions committed to by
[LICENSEE] in this document. Any other statements in this submittal are
provided for information purposes and are not considered to be
regulatory commitments. Please direct questions regarding these
commitments to [CONTACT NAME].
------------------------------------------------------------------------
Regulatory commitments Due date/event
------------------------------------------------------------------------
[LICENSEE] will follow the guidance [Ongoing, or implement with
established in Section 11 of NUMARC 93- amendment]
01, ``Industry Guidance for Monitoring
the Effectiveness of Maintenance at
Nuclear Power Plants,'' Nuclear
Management and Resource Council, Revision
3, July 2000.
[LICENSEE] will follow the guidance [Implement with amendment,
established in TSTF-IG-07-01, when TS Required Action End
Implementation Guidance for TSTF-431, State remains within the
Revision 1, ``Change in Technical APPLICABILITY of TS]
Specifications End-States, BAW-2441-A,''
April 2007.
------------------------------------------------------------------------
ATTACHMENT 5--Proposed Changes to Technical Specification Bases Pages
Proposed No Significant Hazards Consideration Determination
Description of Amendment Request: A change is proposed to the
technical specifications (TS) of [plant name], consistent with
Technical Specifications Task Force (TSTF) change TSTF-431, Revision 2,
to the standard technical specifications (STS) for B&W Plants (NUREG
1430) to allow, for some systems, entry into hot shutdown rather than
cold shutdown to repair equipment, if risk is assessed and managed
consistent with the program in place for complying with the
requirements of 10 CFR 50.65(a)(4). Changes proposed will be made to
the [plant name] TS for selected Required Action end-states providing
this allowance.
Basis for proposed no-significant-hazards-consideration
determination: As required by 10 CFR 50.91(a), an analysis of the issue
of no-significant-hazards consideration is presented below:
Criterion 1--The Proposed Change Does Not Involve a Significant
Increase in the Probability or Consequences of an Accident Previously
Evaluated
The proposed change allows a change to certain required end-states
when the TS Completion Times for remaining in power operation will be
exceeded. Most of the requested technical specification (TS) changes
are to permit an end-state of hot shutdown (Mode 4) rather than an end-
state of cold shutdown (Mode 5) contained in the current TS. The
request was limited to: (1) those end-states where entry into the
shutdown mode is for a short interval, (2) entry is initiated by
inoperability of a single train of equipment or a restriction on a
plant operational parameter, unless otherwise stated in the applicable
technical specification, and (3) the primary purpose is to correct the
initiating condition and return to power operation as soon as is
practical. Risk insights from both the qualitative and quantitative
risk assessments were used in specific TS assessments. Such assessments
are documented in Sections 4 and 5 of BAW-2441-A, Revision 2, ``Risk
Informed Justification for LCO End-State Changes,'' for B&W Plants.
They provide an integrated discussion of deterministic and
probabilistic issues, focusing on specific technical specifications,
which are used to support the proposed TS end-state and associated
restrictions. The staff finds that the risk insights support the
conclusions of the specific TS assessments. Therefore, the probability
of an accident previously evaluated is not significantly increased, if
at all. The consequences of an accident after adopting proposed TSTF-
431, Revision 2, are no different than the consequences of an accident
prior to its adoption. Therefore, the consequences of an accident
previously evaluated are not significantly affected by this change. The
addition of a requirement to assess and manage the risk introduced by
this change will further minimize possible concerns. Therefore, this
change does not involve a significant increase in the probability or
consequences of an accident previously evaluated.
Criterion 2--The Proposed Change Does Not Create the Possibility of a
New or Different Kind of Accident From Any Previously Evaluated
The proposed change does not involve a physical alteration of the
plant (no new or different type of equipment will be installed). If
risk is assessed and managed, allowing a change to certain required
end-states when the TS Completion Times for remaining in power
operation are exceeded, i.e., entry into hot shutdown rather than cold
shutdown to repair equipment, will not introduce new failure modes or
effects and will not, in the absence of other unrelated failures, lead
to an accident whose consequences exceed the consequences of accidents
previously evaluated. The addition of a requirement to assess and
manage the risk introduced by this change and the commitment by the
licensee to adhere to the guidance in TSTF-IG-07-01, Implementation
Guidance for TSTF-431, Revision 1, ``Changes in Technical
Specifications End-States, BAW-2441-A,'' will further minimize possible
concerns. Thus, this change does not create the possibility of a new or
different kind of accident from an accident previously evaluated.
Criterion 3--The Proposed Change Does Not Involve a Significant
Reduction in the Margin of Safety
The proposed change allows, for some systems, entry into hot
shutdown rather than cold shutdown to repair equipment, if risk is
assessed and managed. The B&WOG's risk assessment approach is
comprehensive and follows staff guidance as documented in RGs 1.174 and
1.177. In addition, the analyses show that the criteria of the
[[Page 65629]]
three-tiered approach for allowing TS changes are met. The risk impact
of the proposed TS changes was assessed following the three-tiered
approach recommended in RG 1.177. A risk assessment was performed to
justify the proposed TS changes. The net change to the margin of safety
is insignificant. Therefore, this change does not involve a significant
reduction in a margin of safety.
Based upon the reasoning presented above and the previous
discussion of the amendment request, the requested change does not
involve a significant hazards consideration.
Dated at Rockville, Maryland, this 14th day of November, 2007.
For the Nuclear Regulatory Commission.
Timothy J. Kobetz,
Section Chief, Technical Specifications Branch, Division of Inspection
& Regional Support, Office of Nuclear Reactor Regulation.
[FR Doc. E7-22738 Filed 11-20-07; 8:45 am]
BILLING CODE 7590-01-P