[Federal Register Volume 82, Number 207 (Friday, October 27, 2017)]
[Notices]
[Pages 49859-49869]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-23427]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-336; NRC-2017-0197]
Dominion Nuclear Connecticut, Inc.; Millstone Power Station, Unit
No. 2, Request for Exemption Regarding the Use of Operator Manual
Actions
AGENCY: Nuclear Regulatory Commission.
ACTION: Exemption; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an
exemption in response to an October 28, 2016, request from Dominion
Nuclear Connecticut, Inc. (the licensee, Dominion) for Millstone Power
Station, Unit No. 2 (Millstone 2), Docket No. 50-336, for the use of
operator manual actions (OMAs) in lieu of meeting the circuit
separation and protection requirements for four plant fire areas.
DATES: The exemption was issued on October 24, 2017.
ADDRESSES: Please refer to Docket ID NRC-2017-0197 when contacting the
NRC about the availability of information regarding this document. You
may obtain publicly-available information related to this document
using any of the following methods:
Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2017-0197. Address
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: [email protected]. For technical questions, contact
the individual listed in the FOR FURTHER INFORMATION CONTACT section of
this document.
NRC's Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly-available documents online in the
ADAMS Public Documents collection at http://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS,
please contact the NRC's Public Document Room (PDR) reference staff at
1-800-397-4209, 301-415-4737, or by email to [email protected]. The
ADAMS accession number for each document referenced (if it is available
in ADAMS) is provided the first time that it is mentioned in this
document.
NRC's PDR: You may examine and purchase copies of public
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555
Rockville Pike, Rockville, Maryland 20852.
FOR FURTHER INFORMATION CONTACT: Richard Guzman, Office of Nuclear
[[Page 49860]]
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-1030, email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Background
Dominion is the holder of Renewed Facility Operating License No.
DPR-65, which authorizes operation of Millstone 2. The license
provides, among other things, that the facility is subject to all
rules, regulations, and orders of the NRC, now or hereafter in effect.
Millstone 2 shares the site with Millstone Power Station, Unit No.
1, a permanently defueled boiling-water reactor nuclear unit, and
Millstone Power Station, Unit No. 3, a pressurized-water reactor. The
facility is located in Waterford, Connecticut, approximately 3.2 miles
southwest of New London, Connecticut. This exemption applies to
Millstone 2 only. The other units, Millstone 1 and 3, are not part of
this exemption.
II. Request/Action
Section 50.48 of title 10 of the Code of Federal Regulations (10
CFR), requires that nuclear power plants that were licensed before
January 1, 1979, satisfy the requirements of appendix R to 10 CFR part
50, section III.G, ``Fire protection of safe shutdown capability.''
Millstone 2 was licensed to operate prior to January 1, 1979. As such,
the licensee's fire protection program (FPP) must provide the
established level of protection as intended by section III.G.
By letter dated October 28, 2016 (ADAMS Accession No. ML16305A330),
the licensee requested an exemption for Millstone 2 from certain
technical requirements of 10 CFR part 50, appendix R, section III.G.2
(III.G.2), for the use of OMAs in lieu of meeting the circuit
separation and protection requirements contained in section III.G.2 for
fire areas R-9, R-10, R-13, and R-14.
III. Discussion
Pursuant to Sec. 50.12, the Commission may, upon application by
any interested person or upon its own initiative, grant exemptions from
the requirements of 10 CFR part 50 when the exemptions are authorized
by law, will not present an undue risk to public health or safety, and
are consistent with the common defense and security. However, Sec.
50.12(a)(2) states that the Commission will not consider granting an
exemption unless special circumstances are present as set forth in
Sec. 50.12(a)(2). Under Sec. 50.12(a)(2)(ii), special circumstances
are present when application of the regulation in the particular
circumstances would not serve, or is not necessary to achieve, the
underlying purpose of the rule.
The licensee stated that special circumstances are present in that
the application of the regulation in this particular circumstance is
not necessary to achieve the underlying purpose of the rule, which is
consistent with the language included in Sec. 50.12(a)(2)(ii). The
licensee further stated that the OMAs included in the exemption request
provide assurance that one train of systems necessary to achieve and
maintain hot shutdown will remain available in the event of a fire.
In accordance with Sec. 50.48(b), nuclear power plants licensed
before January 1, 1979, are required to meet section III.G. The
underlying purpose of section III.G is to ensure that the ability to
achieve and maintain safe shutdown is preserved following a fire event.
The regulation intends for licensees to accomplish this by extending
the concept of defense-in-depth (DID) to:
a. Prevent fires from starting;
b. Rapidly detect, control, and extinguish promptly those fires
that do occur;
c. Provide protection for structures, systems, and components
(SSCs) important to safety so that a fire that is not promptly
extinguished by the fire suppression activities will not prevent the
safe shutdown of the plant.
The stated purpose of section III.G.2 is to ensure that in the
event of a fire, one of the redundant trains necessary to achieve and
maintain hot shutdown conditions remains free of fire damage. Section
III.G.2 requires one of the following means to ensure that a redundant
train of safe shutdown cables and equipment is free of fire damage
where redundant trains are located in the same fire area outside of
primary containment:
a. Separation of cables and equipment by a fire barrier having a 3-
hour rating;
b. Separation of cables and equipment by a horizontal distance of
more than 20 feet with no intervening combustibles or fire hazards and
with fire detectors and an automatic fire suppression system installed
in the fire area; or
c. Enclosure of cables and equipment of one redundant train in a
fire barrier having a 1-hour rating and with fire detectors and an
automatic fire suppression system installed in the fire area.
The licensee stated that the OMAs addressed in the exemption
request are those contained in the Millstone 2 10 CFR part 50, appendix
R compliance report (report). The licensee also stated that the
Millstone 2 appendix R report was submitted to the NRC for review on
May 29, 1987 (ADAMS Legacy Accession No. 8706120088), and found
acceptable by an NRC safety evaluation report (SER) dated July 17, 1990
(ADAMS Accession No. ML012880391). However, the SER did not
specifically evaluate the OMAs (i.e., pursuant to Sec. 50.12).
By letter dated June 30, 2011 (ADAMS Accession No. ML11188A213), as
revised by letter dated October 29, 2012 (ADAMS Accession No.
ML12318A128), the licensee submitted an exemption request for the OMAs
contained in the Millstone 2 appendix R report. However, four OMAs
related to loss of instrument air for four specific fire areas were
removed by letter dated February 29, 2012 (ADAMS Accession No.
ML12069A016) because the loss of instrument air was not considered a
postulated event. The NRC approved the revised exemption by NRC letter
dated December 18, 2012 (ADAMS Accession No. ML12312A373).
During the 2016 triennial fire inspection (ADAMS Accession No.
ML16258A175), it was identified that a loss of offsite power will
result in a loss of instrument air prior to the emergency diesel
generators starting. Since instrument air does not automatically
restart, nor can it be manually started from the control room, the
licensee has submitted this exemption request for those four OMAs
related to loss of instrument air for the four specific fire areas.
Each OMA included in this review consists of a sequence of tasks to
be performed in various fire areas upon confirmation of a fire in a
particular fire area. Table 1 lists the OMAs included in this review
(OMAs are listed in the order they are conducted for a fire originating
in a particular area). Some OMAs are listed more than once if they are
needed for fires that originate in different areas.
[[Page 49861]]
Table 1
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Required OMA Postulated damage
OMA No. OMA description Area of fire origin OMA location completion time Equipment type
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1.................... Manually open valve R-10.................... R-4/A-6A (AppR-2).. Within 72 minutes 2-CH-192, Refueling Cable damage or
to establish after restoring Water Storage Tank loss of instrument
charging pump charging. (RWST) Isolation air.
suction. Valve.
1.................... Manually open valve R-9, R-13, and R-14..... R-4/A-6A (AppR-2).. Within 72 minutes 2-CH-192, RWST Loss of instrument
to establish after restoring Isolation Valve. air.
charging pump charging.
suction.
9.................... Control at Fire R-13, R-14.............. R-2/T-10 (AppR-9), Within 45 minutes 2-FW-43B, Auxiliary Loss of instrument
Shutdown Panel C- R-3/T-1A (AppR-7). after loss of main Feedwater (AFW) air.
10 until loss of feedwater. Flow Control Valve.
backup air or
local manual
operation.
10................... Manually operate R-10.................... R-17/A-10C (AppR-6) After establishing 2-MS-190A, Cable damage or
valve to AFW. Atmospheric Dump loss of instrument
transition main Valve. air.
steam safety
valves (MSSVs).
11................... Control at Fire R-9, R-14............... R-2/T-10(C-10) After establishing 2-MS-190B, Cable damage or
Shutdown Panel C- (AppR-9), R-2/A-8E AFW. Atmospheric Dump loss of instrument
10 (R-13 fire) (Manual operation) Valve. air.
until loss of air, (AppR-6).
manually operate
valve to
transition from
MSSVs.
11................... Control at Fire R-13.................... R-2/T-10(C-10) After establishing 2-MS-190B, Loss of instrument
Shutdown Panel C- (AppR-9), R-2/A-8E AFW. Atmospheric Dump air.
10 (R-13 fire) (Manual operation) Valve.
until loss of air, (AppR-6).
manually operate
valve to
transition from
MSSVs.
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The designations Z1 and Z2 are used throughout this exemption. The
licensee stated that the 4.16 kilovolt (kV) subsystems are divided into
two specific ``facilities.'' Facility Z1 powers one train of engineered
safety features (ESFs) and is provided with an emergency power supply
by the ``A'' emergency diesel generator (EDG). Facility Z2 powers a
redundant second train of ESF and is provided with an emergency power
supply by the ``B'' EDG. The licensee also stated that vital power and
control cables fall mainly into two redundancy classifications: Channel
Z1 and Channel Z2, and that in a few cases, there is also a Channel Z5,
which is a system that can be transferred from one source to another.
The licensee further stated that Facility Z1 would be synonymous with
``A'' train, while Facility Z2 would be synonymous with ``B'' train.
The licensee stated that its exemption request is provided in
accordance with the information contained in NRC Regulatory Issue
Summary 2006-10, ``Regulatory Expectations with Appendix R Paragraph
III.G.2 Operator Manual Actions,'' dated June 30, 2006, which states
that an approved Sec. 50.12 exemption is required for all OMAs, even
those accepted in a previously issued NRC SER.
As indicated above, the licensee has requested an exemption from
the requirements of section III.G.2 for Millstone 2 to the extent that
one of the redundant trains of systems necessary to achieve and
maintain hot shutdown is not maintained free of fire damage in
accordance with one of the required means for a fire occurring in the
following fire areas:
R-9 Facility Z1 DC switchgear room and battery room,
R-10 Facility Z2 DC switchgear room and battery room;
R-13 west 480 VAC switchgear room;
R-14 Facility Z1 lower 4.16kV switchgear room and cable
vault.
The licensee stated that the OMAs are credited for the section
III.G.2 deficiencies, such as having only a single safe shutdown train,
lack of separation between redundant trains, lack of detection and
automatic suppression in the fire area, or a combination of those
deficiencies. The NRC staff notes that having only a single safe
shutdown train is not uncommon to this plant design. Single train
systems at Millstone 2 include IA, ``A'' and ``B'' boric acid storage
tank (BAST) control room (CR) level indication, condensate storage tank
(CST) CR level indication, suction-side flow to the charging pumps from
the refueling water storage tank (RWST), auxiliary spray to the
pressurizer, and charging pump discharge to the reactor coolant system
(RCS).
The licensee also stated that it has evaluated and modified all
motor-operated valves (MOVs) relied upon by OMAs consistent with NRC
Information Notice 92-18, ``Potential for Loss of Remote Shutdown
Capability During a Control Room Fire,'' dated February 28, 1992, which
details the potential for fires to damage MOVs that are required for
safe shutdown so that they can no longer be remotely or manually
operated, and that as a result of this evaluation and modifications,
the possibility that the desired result was not obtained is minimized.
The licensee further stated that all the equipment operated to perform
these OMAs is not fire affected and, therefore, is reasonably expected
to operate as designed.
In its submittals, the licensee described elements of its FPP that
provide its justification that the concept of DID in place in the above
fire areas is consistent with that intended by the regulation. To
accomplish this, the licensee utilizes various protective measures to
accomplish the concept of DID. Specifically, the licensee stated that
the purpose of its request was to credit the use of OMAs, in
conjunction with other DID features, in lieu of the separation and
protective measures required by 10 CFR part 50, appendix R, section
III.G.2.
The licensee indicated that its FPP uses the concept of DID, both
procedurally and physically, to meet the following objectives:
1. Prevent fires from starting;
2. Rapidly detect, control, and extinguish promptly those fires
that do occur; and
3. Provide protection for SSCs important to safety so that a fire
that is not promptly extinguished by the fire suppression activities
will not prevent the safe shutdown of the plant.
[[Page 49862]]
The licensee provided an analysis that described how fire
prevention is addressed for each of the fire areas for which the OMAs
may be required. Unless noted otherwise below, all of the fire areas
included in this exemption have a combustible fuel load that is
considered to be low, with fuel sources consisting primarily of fire-
retardant cable insulation and limited floor-based combustibles. There
are no high energy ignition sources located in the areas except as
noted in fire area R-14. The fire areas included in the exemption
request are not shop areas, so hot work activities are infrequent with
administrative control (e.g., hot work permits, fire watch, and
supervisory controls) programs in place if hot work activities do
occur. The administrative controls are described in the Millstone FPP,
which is incorporated into the Updated Final Safety Analysis Report.
The licensee stated that the storage of combustibles is
administratively controlled by the site's FPP procedures to limit the
effects of transient fire exposures on the plant and in addition, hot
work (i.e., welding, cutting, grinding) is also administratively
controlled by a site FPP procedure.
The licensee also stated that the integration of the program,
personnel, and procedures, which are then collectively applied to the
facility, reinforce the DID aspect of the FPP and that strict
enforcement of ignition source and transient combustible control
activities (through permitting) and monthly fire prevention inspections
by the site fire marshal ensure that this work is actively monitored to
prevent fires.
The licensee stated that the Millstone fire brigade consists of a
minimum of a Shift Leader and four fire brigade personnel. The affected
unit (Millstone 2 or Millstone 3) supplies an advisor, who is a
qualified Plant Equipment Operator (PEO). The advisor provides
direction and support concerning plant operations and priorities.
Members of the fire brigade are trained in accordance with Millstone
procedures. Fire brigade personnel are responsible for responding to
all fires, fire alarms, and fire drills. To ensure availability, a
minimum of a Shift Leader and four fire brigade personnel remain in the
owner-controlled area and do not engage in any activity that would
require a relief in order to respond to a fire. The licensee further
stated that the responding fire brigade lead may request the Shift
Manager augment the on-shift five-member fire brigade with outside
resources from the Town of Waterford Fire Department, which has a
letter of agreement with Millstone, to respond to the site (when
requested) in the event of a fire emergency or rescue and will attempt
to control the situation with available resources.
Millstone 2 has been divided into fire areas, as described in the
Millstone FPP. Three-hour fire barriers are normally used to provide
fire resistive separation between adjacent fire areas. In some cases,
barriers with a fire resistance rating of less than 3 hours are
credited, but exemptions have been approved, or engineering evaluations
performed, in accordance with Generic Letter (GL) 86-10,
``Implementation of Fire Protection Requirements,'' to demonstrate that
the barriers are sufficient for the hazard. Walls separating rooms
within fire areas are typically constructed of concrete. The licensee
stated that in general, fire-rated assemblies separating appendix R
fire areas meet Underwriters Laboratories/Factory Mutual (UL/FM) design
criteria and the requirements of American Society of Testing Materials
(ASTM) E-119, ``Fire Tests of Building Construction and Materials,''
for 3-hour rated fire assemblies. The licensee also stated that
openings created in fire-rated assemblies are sealed utilizing
penetration seal details that have been tested in accordance with ASTM
E-119 and are qualified for a 3-hour fire rating. In addition,
fireproof coating of structural steel conforms to UL-listed recognized
details and is qualified for a 3-hour fire rating. The licensee further
stated that fire dampers are UL-listed and have been installed in
accordance with the requirements of National Fire Protection
Association (NFPA) 90A, ``Standard for the Installation of Air-
Conditioning and Ventilation Systems,'' and that the code of record for
fire dampers is either the version in effect at the time of original
plant construction (late 1960s) or the 1985 edition. The licensee
further stated that fire doors are UL-listed and have been installed in
accordance with NFPA 80, ``Standard for Fire Doors and Windows,'' in
effect in the late 1960s, at the time of plant construction.
The licensee provided a discussion of the impacts of any GL 86-10
evaluations and/or exemptions on the fire areas included in this
exemption request. For all the areas with GL 86-10 evaluations and/or
other exemptions, the licensee stated that none of the issues addressed
by the evaluations would adversely impact, through the spread of fire
or products of combustion, plant areas where OMAs are performed or the
respective travel paths necessary to reach these areas. The licensee
also stated that there are no adverse impacts on the ability to perform
OMAs and that the conclusions of the GL 86-10 evaluations and the
exemption requests would remain valid with the OMAs in place. In
addition to these boundaries, the licensee provided a hazard analysis
that described how detection, control, and extinguishment of fires are
addressed for each of the fire areas for which the OMAs may be needed.
Unless noted otherwise below, fire areas are provided with
ionization smoke detectors. The licensee stated that the smoke and heat
detection systems were designed and installed using the guidance of the
requirements set forth in several NFPA standards, including the 1967,
1979, and 1986 Editions of NFPA 72D, ``Standard for the Installation,
Maintenance and Use of Proprietary Protective Signaling Systems for
Watchman, Fire Alarm and Supervisory Service,'' and the 1978 and 1984
Editions of NFPA 72E, ``Standard on Automatic Fire Detectors.'' Upon
detecting smoke or fire, the detectors initiate an alarm in the CR
enabling fire brigade response. The licensee stated that in most cases,
no automatic fire suppression systems are provided in the areas
included in this exemption request except for plant areas with
significant quantities of combustibles, such as lube oil. Automatic
fire suppression systems have also been installed in areas with 1-hour
barrier walls and 1-hour rated electrical raceway encapsulation.
The licensee stated that fire suppression systems were designed in
general compliance with, and to meet the intent of, the requirements of
several NFPA standards, depending on the type of system, including the
1985 Edition of NFPA 13, ``Standard for the Installation of Sprinkler
Systems''; the 1985 Edition of NFPA 15, ``Standard for Water Spray
Fixed Systems For Fire Protection''; and the 1987 Edition of NFPA 12A,
``Standard on Halon 1301 Fire Extinguishing Systems.''
The licensee stated that, in general, fire extinguishers and hose
stations have been installed in accordance with the requirements of the
1968 Edition of NPFA 10, ``Standard for the Installation of Portable
Fire Extinguishers,'' and the 1978 Edition of NFPA 14, ``Standard for
the Installation of Standpipe and Hose Systems,'' respectively. The
licensee stated that Equipment Operators are trained fire brigade
members and would likely identify and manually suppress or extinguish a
fire using the portable fire extinguishers and manual hose stations
located either in or adjacent to, or both, these fire areas.
Each of the fire areas included in this exemption is analyzed below
with regard to how the concept of DID is achieved for each area and the
role of
[[Page 49863]]
the OMAs in the overall level of safety provided for each area.
A.1 Fire Area R-9, ``A'' East DC Equipment Room
A.1.1 Fire Prevention
The licensee stated that the area has low combustible loading that
predominantly consists of cable insulation, and that potential ignition
sources include electrical faults.
A.1.2 Detection, Control, and Extinguishment
The licensee stated that the area is provided with a cross-zoned
ionization and photoelectric smoke detection system that activates a
total flooding Halon 1301 fire suppression system and that the Halon
1301 suppression system has manual release stations at each doorway and
an abort switch located at the doorway to the east CR/cable vault
stairway. The licensee also stated that this system alarms locally at
the Halon control panel and at the main fire alarm panel in the CR. The
licensee further stated that duct smoke detection is provided between
this area, the ``B'' (west) DC equipment room (fire hazard analysis
(FHA) Zone A-21), and the auxiliary building cable vault (FHA Zone A-
24) and that this system alarms at a local panel and at the main fire
alarm panel in the CR. The licensee further stated that a fire in the
area that could potentially impact any cables of concern would likely
involve cable insulation resulting from an electrical fault or failure
of a bus or electrical panel located in the room and that combustibles
in this area consist predominantly of Institute of Electrical and
Electronics Engineers (IEEE) 383 qualified cable insulation or cable
that has been tested and found to have similar fire resistive
characteristics. The licensee further stated that since there is a
minimal amount of Class A combustibles in this area, there is little
chance of a fire occurring outside of a bus/electrical panel failure,
which could act as a pilot ignition source for the cable insulation and
that a bus/electrical panel failure normally results in a high
intensity fire that lasts for a short duration, which makes it unlikely
that it will cause sustained combustion of IEEE 383 qualified cables.
The licensee further stated that in the unlikely event of a fire in
this area, it would be rapidly detected by the cross-zoned ionization
and photoelectric smoke detection smoke detection system, subsequently
extinguished by the total flooding Halon 1301 suppression system, and
the smoke detection system would also aid in providing prompt fire
brigade response.
A.1.3 Preservation of Safe Shutdown Capability
The licensee stated that the OMAs associated with a fire in the
area are related to a loss of IA or a loss of power to the ``A'' DC
buses (such as DV10) and that cables for valves 2-CH-192, 2-CH-508, and
2-CH-509 do not pass through this room.
The licensee stated that a fire in the area will affect all
Facility Z1 shutdown components that Facility Z2 is used to achieve and
maintain Hot Standby, and that plant shutdown to Hot Standby can be
accomplished using an abnormal operating procedure (AOP).
A.1.4 OMAs Credited for a Fire in This Area
The licensee stated that OMAs 1 and 11 are credited for a fire
originating in Fire Area R-9 in order to provide decay heat removal and
restore charging system flow to RCS in the event of cable damage or
loss of IA.
A.1.4.1 Auxiliary Feedwater (AFW) and Charging System Flow
A.1.4.1.1 OMAs 1 and 11 Open Valve 2-CH-192 and Control Valve 2-MS-190B
at Panel C10 or Local Manual Operation
The licensee stated that establishing AFW flow to the credited
steam generator (SG) is required to be accomplished within 45 minutes
and that the required flow path utilizes the turbine driven auxiliary
feedwater (TDAFW) pump. The licensee also stated that prior to AFW
initiation, the plant is placed in the Hot Standby condition by
steaming through the main steam safety valves (MSSVs) and that after
AFW is established from the CR, operation of the atmospheric dump valve
(ADV) (2-MS-190B) (OMA 11) is the required method of removing decay
heat to maintain Hot Standby and transition to Cold Shutdown. The
licensee further stated that there is no cable damage from fire to the
required ADV (2-MS-190B); however, the fire may cause a loss of IA,
which is required to operate the ADVs to support decay heat removal.
The licensee stated that upon a loss of air, the ADV will fail closed
and that this design prevents excessive RCS cooldown prior to AFW
start; therefore, in the event of a loss of IA, Operators will
establish local manual control of 2-MS-190B after AFW flow is
established. The licensee further stated that PEO-2 will remain with
the ADV to modulate steam flow per direction from the CR and that after
restoration of the charging system, the BASTs are credited for
maintaining RCS inventory and that the BASTs have a minimum level
specified in the technical requirements manual (TRM), which ensures 72
minutes of flow. The licensee further stated that once the BASTs are
depleted, Operators switch over to the RWST. The licensee further
stated that due to fire damage, the 2-CH-192 valve may spuriously close
and in order to establish the RWST as the suction path for the charging
system, an OMA is required to open valve 2-CH-192 (OMA 1) prior to BAST
depletion. OMA 1 establishes the RWST as the suction supply for the
charging system and is not conducted until after AFW is established.
A.1.4.2 OMA Timing
AFW flow is established from the CR within the required 45-minute
time period. Should IA be lost, the OMA to continue decay heat removal
can be conducted beginning 17 minutes after AFW flow is established?
The OMA to establish charging system flow from the RWST prior to BAST
depletion can be completed in 32 minutes, which provides a 40-minute
margin, since the required completion time is 72 minutes.
A.1.5 Conclusion
Given the limited amount of combustible materials and ignition
sources and installed detection and suppression, it is unlikely that a
fire would occur and go undetected or unsuppressed by the personnel and
damage the safe shutdown equipment. The low likelihood of damage to
safe shutdown equipment due to a fire in this area, combined with the
ability of the OMAs to manipulate the plant in the event of a fire that
damages safe shutdown equipment and to be completed with more than 30
minutes of margin, provides adequate assurance that safe shutdown
capability is maintained.
A.2 Fire Area R-10, ``B'' West Direct Current (DC) Equipment Room
A.2.1 Fire Prevention
The licensee stated that the area has low combustible loading that
predominantly consists of cable insulation, and that potential ignition
sources include electrical faults.
A.2.2 Detection, Control, and Extinguishment
The licensee stated that the area is provided with a cross-zoned
ionization and photoelectric smoke detection system that activates a
total flooding Halon 1301 fire suppression system and that the Halon
1301 suppression system has manual release stations at each
[[Page 49864]]
doorway and an abort switch located at the doorway to the ``A'' (east)
DC equipment room (FHA Zone A-20). The licensee also stated that this
system alarms locally on the Halon control panel and at the main fire
alarm panel in the CR. The licensee further stated that duct smoke
detection is provided between this fire area, the ``A'' (east) DC
equipment room (FHA Zone A-20), and the AB cable vault (FHA Zone A-24),
and that this system alarms at a local panel and at the main fire alarm
panel in the CR. The licensee further stated that a fire in the area
that could potentially impact any cables of concern would likely
involve cable insulation resulting from an electrical fault or failure
of a bus or electrical panel located in the room and that combustibles
in this area consist predominantly of IEEE 383 qualified cable
insulation or cable that has been tested and found to have similar fire
resistive characteristics. The licensee further stated that since there
is a minimal amount of Class A combustibles in this area, there is
little chance of a fire occurring outside of a bus/electrical panel
failure, which could act as a pilot ignition source for the cable
insulation, and that a bus/electrical panel failure normally results in
a high intensity fire that lasts for a short duration, which makes it
unlikely that it will cause sustained combustion of IEEE 383 qualified
cables. The licensee further stated that in the unlikely event of a
fire in this area, it would be rapidly detected by the cross-zoned
ionization and photoelectric smoke detection smoke detection system and
subsequently extinguished by the total flooding Halon 1301 suppression
system installed in this area and that the smoke detection system would
also aid in providing prompt fire brigade response.
A.2.3 Preservation of Safe Shutdown Capability
The licensee stated that the OMAs associated with a fire in the
area are related to loss of power to the ``B'' AC vital power panels
(such as VA20) and that cables for level transmitters LT-206, LT-208,
and LT-5282 do not pass through this room.
The licensee stated that a fire in the area will affect all
Facility Z2 shutdown components that Facility Z1 is used to achieve and
maintain Hot Standby, and that plant shutdown to Hot Standby can be
accomplished using an AOP.
A.2.4 OMAs Credited for a Fire in This Area
The licensee stated that OMAs 1 and 10 are credited for a fire
originating in R-10 to provide decay heat removal and restore charging
system flow to RCS in the event of cable damage or loss of IA.
A.2.4.1 AFW and Charging System Flow
A.2.4.1.1 OMAs 1 and 10 Open Valve 2-CH-192 and Control Valve 2-MS-190A
The licensee stated that establishing AFW flow to the credited SG
is required to be accomplished within 45 minutes and that the required
flow path utilizes the TDAFW pump. The licensee also stated that prior
to AFW initiation, the plant is placed in the Hot Standby condition by
steaming through the MSSVs and that after AFW is established from the
CR, operation of the ADV (2-MS-190A) (OMA 10) is the required method of
removing decay heat to maintain Hot Standby and transition to Cold
Shutdown. The licensee further stated that there is no cable damage
from fire to the required ADV (2-MS-190A); however, the fire may cause
a loss of IA which is required to operate the ADVs to support decay
heat removal. The licensee stated that upon a loss of air, the ADV will
fail closed and that this design prevents excessive RCS cooldown prior
to AFW start and, therefore, in the event of a loss of IA, Operators
will establish local manual control of 2-MS-190A after AFW flow is
established. The licensee further stated that PEO-1 will remain with
the ADV to modulate steam flow per direction from the CR and that after
restoration of the charging system, the BASTs are credited for
maintaining RCS inventory and that the BASTs have a minimum level
specified in the TRM which ensures 72 minutes of flow. The licensee
further stated that once the BASTs are depleted, Operators switch over
to the RWST. The licensee further stated that due to fire damage, the
2-CH-192 valve may spuriously close and that in order to establish the
RWST as the suction path for the charging system, an OMA is required to
open valve 2-CH-192 (OMA 1) prior to BAST depletion. OMA 1 establishes
the RWST as the suction supply for the charging system and is not
conducted until after AFW is established.
A.2.4.2 OMA Timing
AFW flow is established from the CR within the required 45-minute
time period and should IA be lost, the OMA to continue decay heat
removal can be conducted beginning 17 minutes after AFW flow is
established. The OMA to establish charging system flow from the RWST
prior to BAST depletion can be completed in 24 minutes, which provides
a 48-minute margin, since the required completion time is 72 minutes.
A.2.5 Conclusion
Given the limited amount of combustible materials and ignition
sources and installed detection and suppression, it is unlikely that a
fire would occur and go undetected or unsuppressed by the personnel and
damage the safe shutdown equipment. The low likelihood of damage to
safe shutdown equipment due to a fire in this area, combined with the
ability of the OMAs to manipulate the plant in the event of a fire that
damages safe shutdown equipment and to be completed with more than 30
minutes of margin, provides adequate assurance that safe shutdown
capability is maintained.
A.3 Fire Area R-13, West 480 V Load Center Room
A.3.1 Fire Prevention
The licensee stated that the area has low combustible loading that
predominantly consists of cable insulation and that potential ignition
sources include electrical faults.
A.3.2 Detection, Control, and Extinguishment
The licensee stated that the area is provided with ionization smoke
detection that alarms at the main fire alarm panel in the CR. The
licensee also stated that a fire in the area that could potentially
impact any cables of concern would likely involve cable insulation
resulting from an electrical fault or a bus failure and that
combustibles in the area consist predominantly of IEEE 383 qualified
cable insulation or cable that has been tested and found to have
similar fire resistive characteristics. The licensee further stated
that since there is a minimal amount of Class A combustibles in this
area, there is little chance of a fire occurring outside of a bus
failure, which could act as a pilot ignition source for the cable
insulation, and that a bus failure normally results in a high intensity
fire that lasts for a short duration, which makes it unlikely that it
will cause sustained combustion of IEEE 383 qualified cables. The
licensee further stated that in the unlikely event of a fire, it would
be rapidly detected by the ionization smoke detection system installed
in the area and that the smoke detection system will aid in providing
prompt fire brigade response.
A.3.3 Preservation of Safe Shutdown Capability
The licensee stated that the components of concern for the area are
[[Page 49865]]
for valves 2-CH-192, 2-CH-508, 2-CH-509, 2-FW-43B and 2-MS-190B;
breaker A406, H21 (TDAFW speed control circuit); level transmitter LT-
5282, P18C (``C'' charging pump); SV-4188 (TDAFW steam supply valve);
and breaker DV2021.
The licensee stated that a fire in the area will affect Facility Z1
safe shutdown equipment, the ``A'' EDG will be unavailable due to a
loss of the Facility Z1 power supply for the diesel room ventilation
fan F38A, Facility Z2 is used to achieve and maintain Hot Standby, and
plant shutdown to Hot Standby can be accomplished using an AOP.
A.3.4 OMAs Credited for a Fire in This Area
The licensee stated that OMAs 1, 9, and 11 are credited for a fire
originating in Fire Area R-13 in order to provide decay heat removal
and restore charging system flow to RCS in the event of cable damage or
loss of IA.
A.3.4.1 AFW and Charging System Flow
A.3.3.4.1.1 OMAs 1, 9, and 11 Open Valve 2-CH-192, Control AFW Flow
Valve 2-FW-43B, and Control Valve 2-MS-190B at Panel C10 or Local
Manual Operation
The licensee stated that establishing AFW flow to the credited SG
is required to be accomplished within 45 minutes and that the required
flow path utilizes the TDAFW pump. The licensee also stated that prior
to AFW initiation, the plant is placed in the Hot Standby condition by
steaming through the MSSVs and that after AFW is established from the
CR, operation of the ADV (2-MS-190B) (OMA 11) is the required method of
removing decay heat to maintain Hot Standby and transition to Cold
Shutdown. The licensee further stated that there is no cable damage
from fire to the required ADV (2-MS-190B); however, the fire may cause
a loss of IA, which is required to operate the ADVs to support decay
heat removal. The licensee stated that upon a loss of air, the ADV will
fail closed and that this design prevents excessive RCS cooldown prior
to AFW start and, therefore, in the event of a loss of IA, Operators
will establish local manual control of 2-MS-190B after AFW flow is
established. The licensee further stated that PEO-2 will remain with
the ADV to modulate steam flow per direction from the CR and that after
restoration of the charging system, the BASTs are credited for
maintaining RCS inventory and that the BASTs have a minimum level
specified in the TRM, which ensures 72 minutes of flow.
The licensee stated that a loss of IA or power causes AFW flow
control valve 2-FW-43B to fail open. However, the licensee also stated
that the circuit can be isolated and controlled from Fire Shutdown
Panel C-10. Therefore, OMA 9 is required to isolate the damaged cables
and operate the TDAFW turbine speed control to maintain level in the SG
with AFW flow control valve 2-FW-43B failed open. After AFW flow is
established, the licensee stated that the steam release path from the
SG may be switched from the MSSVs to ADV 2-MS-190B using OMA 11, which
will require local manual operation of the valve. The license further
stated that in the event that IA is not lost, ADV 2-MS-190B and AFW
flow control valve 2-FW-43B can be operated from Fire Shutdown Panel C-
10.
The licensee further stated that once the BASTs are depleted,
Operators switch over to the RWST. The licensee further stated that due
to fire damage, the 2-CH-192 valve may spuriously close and that in
order to establish the RWST as the suction path for the charging
system, an OMA is required to open valve 2-CH-192 (OMA 1) prior to BAST
depletion. OMA 1 establishes the RWST as the suction supply for the
charging system and is not conducted until after AFW is established
which takes 17 minutes.
A.3.4.4 OMA Timing
The licensee stated that the OMA for restoring charging (OMA 1)
requires 32 minutes to complete and that the available time is 72
minutes, which results in 40 minutes of margin. The licensee also
stated that the OMA for establishing AFW from Fire Shutdown Panel C-10
(OMA 9) requires 10 minutes to complete and that the time available is
45 minutes, leaving a margin of 35 minutes. AFW flow is established
from the CR within the required 45-minute time period and should IA be
lost, the OMA to continue decay heat removal can be conducted beginning
17 minutes after AFW flow is established (OMA 11).
A.3.5 Conclusion
Given the limited amount of combustible materials and ignition
sources and installed detection, it is unlikely that a fire would occur
and go undetected or unsuppressed by the personnel and damage the safe
shutdown equipment. The low likelihood of damage to safe shutdown
equipment due to a fire in this area, combined with the ability of the
OMAs to manipulate the plant in the event of a fire that damages safe
shutdown equipment and to be completed with more than 30 minutes of
margin, provides adequate assurance that safe shutdown capability is
maintained.
A.4 Fire Area R-14, Lower 6.9 and 4.16 kV Switchgear Room, East Cable
Vault
A.4.1 Fire Prevention
The licensee stated that the areas have low combustible loading
that predominantly consists of cable insulation and Thermo-Lag fire
resistant wrap, and that potential ignition sources include electrical
faults.
A.4.2 Detection, Control, and Extinguishment
The licensee stated that the lower 6.9 and 4.16kV switchgear room
contain ionization smoke detectors located directly over each
switchgear cabinet that alarm at the main fire alarm panel in the CR.
The licensee also stated that a fire in the lower 6.9 and 4.16 kV
switchgear room that could potentially impact cables of concern would
likely involve cable insulation resulting from an electrical fault in
one of the cable trays routed over bus 24E or failure of bus 24E
itself, and that combustibles in this area consist predominantly of
IEEE 383 qualified cable insulation or cable that has been tested and
found to have similar fire resistive characteristics. The licensee
further stated that since there is a minimal amount of Class A
combustibles in this area, there is little chance of a fire occurring
outside of a switchgear failure, which could act as a pilot ignition
source for the cable insulation, and that a switchgear failure normally
results in a high intensity fire that lasts for a short duration, which
makes it unlikely that it will cause sustained combustion of IEEE 383
qualified cables. The licensee further stated that in the unlikely
event of a fire, it would be rapidly detected by the ionization smoke
detection system installed in the area and that the smoke detection
system, which consists of an ionization smoke detector located directly
over each switchgear cabinet in the area, will aid in providing prompt
fire brigade response.
The licensee stated that the east cable vault is provided with an
automatic wet-pipe sprinkler system designed to protect structural
steel and an ionization smoke detection system that alarms at the main
fire alarm panel in the CR. The licensee also stated that the vertical
cable chase that leads down the AB cable vault is protected by an
automatic deluge spray system, which is actuated by cross-zoned smoke
detection system that alarms at a local panel and at the
[[Page 49866]]
main fire alarm panel in the CR. The licensee further stated that a
fire in the area that could potentially impact any cables of concern
would likely involve cable insulation resulting from an electrical
fault and that combustibles in this area consist predominantly of IEEE
383 qualified cable insulation or cable that has been tested and found
to have similar fire resistive characteristics. The licensee further
stated that since there is a minimal amount of Class A combustibles in
this area, there is little chance of a fire occurring that could act as
a pilot ignition source for the cable insulation. The licensee further
stated that Thermo-Lag, while considered combustible, is 1-hour fire-
rated in this area and that based on its fire resistive qualities and
lack of ignition sources, a fire involving Thermo-Lag wrap is not
credible. The licensee further stated that in the event of a fire in
this area, it would be rapidly detected in its incipient stage by the
installed smoke detection system, which will aid in providing rapid
response by the fire brigade and that in the unlikely event the fire
advanced beyond its incipient stage (unlikely based on type of cable
insulation and fire brigade suppression activities), it would actuate
the installed automatic wet-pipe suppression system provided in this
area, which will, at a minimum, provide reasonable assurance that a
cable tray fire in this area will be controlled and confined to the
immediate area of origin.
A.4.3 Preservation of Safe Shutdown Capability
The licensee stated that a fire in the Facility Z1 lower 4.16kV
switchgear room and cable vault will affect all Facility Z1 shutdown
components, that Facility Z2 is used to achieve and maintain Hot
Standby, that plant shutdown to Hot Standby can be accomplished using
an AOP, and that OMAs are required to provide decay heat removal and
restore charging system flow to the RCS.
The licensee stated that the cables of concern in the east cable
vault are the control and indication cabling for valve 2-FW-43B. The
licensee also stated that cables for valves 2-CH-192, 2-CH-508, and 2-
CH-509 are not located in this room; however, valves 2-CH-508 and 2-CH-
509 are impacted due to the potential loss of the feed cables for bus
22E or the ``A'' EDG's control and power cables, which results in the
loss of power to the valves.
A.4.4 OMAs Credited for a Fire in This Area
The licensee stated that OMAs 1, 9, and 11 are credited for a fire
originating in Fire Area R-13 in order to provide decay heat removal
and restore charging system flow to RCS in the event of cable damage or
loss of IA.
A.4.4.1 AFW and Charging System Flow
A.4.4.1.1 OMAs 1, 9, and 11 Open Valve 2-CH-192, Control AFW Flow Valve
2-FW-43B, and Control Valve 2-MS-190B at Panel C10 or Local Manual
Operation
The licensee stated that establishing AFW flow to the credited SG
is required to be accomplished within 45 minutes and that the required
flow path utilizes the TDAFW pump. The licensee also stated that prior
to AFW initiation, the plant is placed in the Hot Standby condition by
steaming through the MSSVs and that after AFW is established from the
CR, operation of the ADV (2-MS-190B) (OMA 11) is the required method of
removing decay heat to maintain Hot Standby and transition to Cold
Shutdown. The licensee further stated that there is no cable damage
from fire to the required ADV (2-MS-190B); however, the fire may cause
a loss of IA, which is required to operate the ADVs to support decay
heat removal. The licensee stated that upon a loss of air, the ADV will
fail closed and that this design prevents excessive RCS cooldown prior
to AFW start and, therefore, in the event of a loss of IA, Operators
will establish local manual control of 2-MS-190B after AFW flow is
established. The licensee further stated that PEO-2 will remain with
the ADV to modulate steam flow per direction from the CR and that after
restoration of the charging system, the BASTs are credited for
maintaining RCS inventory and that the BASTs have a minimum level
specified in the TRM, which ensures 72 minutes of flow.
The licensee stated that a loss of IA or power causes AFW flow
control valve 2-FW-43B to fail open. However, the licensee also stated
that the circuit can be isolated and controlled from Fire Shutdown
Panel C-10. Therefore, OMA 9 is required to isolate the damaged cables
and operate the TDAFW turbine speed control to maintain level in the SG
with AFW flow control valve 2-FW-43B failed open. After AFW flow is
established, the licensee stated that the steam release path from the
SG may be switched from the MSSVs to ADV 2-MS-190B using OMA 11, which
will require local manual operation of the valve. In the event that IA
is not lost, ADV 2-MS-190B and AFW flow control valve 2-FW-43B can be
operated from Fire Shutdown Panel C-10.
The licensee further stated that once the BASTs are depleted,
Operators switch over to the RWST. The licensee further stated that due
to fire damage, the 2-CH-192 valve may spuriously close and that in
order to establish the RWST as the suction path for the charging
system, an OMA is required to open valve 2-CH-192 (OMA 1) prior to BAST
depletion. OMA 1 establishes the RWST as the suction supply for the
charging system and is not conducted until after AFW is established,
which takes 17 minutes.
A.4.4.2 OMA Timing
The licensee stated that the OMA for restoring charging (OMA 1)
requires 32 minutes to complete and that the available time is 72
minutes, which results in 40 minutes of margin. The licensee also
stated that the OMA for establishing AFW from Fire Shutdown Panel C-10
(OMA 9) requires 4 minutes to complete and that the time available is
45 minutes, which results in 41 minutes of margin. AFW flow is
established from the CR within the required 45-minute time period and
should IA be lost, the OMA to continue decay heat removal can be
conducted beginning 17 minutes after AFW flow is established (OMA 11).
A.4.5 Conclusion
Given the limited amount of combustible materials and ignition
sources and installed detection (lower 6.9 and 4.16 kV switchgear room)
and installed detection and suppression (east cable vault), it is
unlikely that a fire would occur and go undetected or unsuppressed by
the personnel and damage the safe shutdown equipment. The low
likelihood of damage to safe shutdown equipment due to a fire in this
area, combined with the ability of the OMAs to manipulate the plant in
the event of a fire that damages safe shutdown equipment and to be
completed with more than 30 minutes of margin, provides adequate
assurance that safe shutdown capability is maintained.
A.5 Feasibility and Reliability of the Operator Manual Actions
The licensee stated that the means to safely shut down Millstone 2
in the event of a fire that does occur and is not rapidly extinguished,
as expected, has been documented in the 10 CFR part 50, appendix R
report. The entire appendix R report was not reviewed by the NRC as
part of this exemption; the relevant information was submitted on the
docket in the letters identified above. The sections below outline the
[[Page 49867]]
licensee's basis for the OMA's feasibility and reliability.
The NUREG-1852, ``Demonstrating the Feasibility and Reliability of
Operator Manual Actions in Response to Fire'' (ADAMS Accession No.
ML073020676), provides criteria and associated technical bases for
evaluating the feasibility and reliability of post-fire OMAs in nuclear
power plants. The following provides the Millstone 2 analysis of these
criteria for justifying the OMAs specified in this exemption.
A.5.1 Bases for Establishing Feasibility and Reliability
The licensee stated that in establishing the assumed times for
Operators to perform various tasks, a significant margin (i.e., a
factor of two) was used with respect to the required time to establish
the system function for all fire area scenarios identified in the
exemption request. The licensee also stated that confirmation times for
valve/breaker manipulations were included in the action time for the
OMAs. The licensee also stated that for valves that are operated in the
field, if they are being manually opened or closed, there is local
indication, plus the mechanical stops to confirm valve operation, and
for valves that are throttled, the field Operator is in communication
with the CR personnel who monitor control board indication to confirm
the proper response. The licensee further stated that all breakers have
local mechanical indication for position verification, that all
sequenced steps are coordinated from the CR, and that the OMA times
listed include this coordination.
A.5.2 Environmental Factors
The licensee stated that a review of ventilation systems for the
fire areas addressed by the exemption request concluded that no
credible paths exist that could allow the spread of products of
combustion from the area of fire origin to an area that either serves
as a travel path for OMAs or is an action location for an OMA. The
licensee also stated that the installed ventilation systems are not
used to perform smoke removal activity for the fire areas discussed in
the exemption request and that smoke evacuation for these areas would
be accomplished by the site fire brigade utilizing portable mechanical
ventilation.
The licensee stated that the performance of all the OMAs for each
of the fire areas has specific safe pathways for access and egress and
that in all cases, emergency lighting units have been provided to
ensure adequate lighting. The licensee also stated that during a fire
event, implementation of CR actions ensure the radiation levels along
these pathways, and at the location of the OMAs, are within the normal
and expected levels.
The licensee stated that area temperatures may be slightly elevated
due to a loss of normal ventilation; however, in no case would the
temperatures prevent access along the defined routes or prevent the
performance of an OMA. The licensee further stated that the most
limiting time estimate is 72 minutes of charging system operation
injecting the contents of the BASTs based on the tanks being at the TRM
minimum level at the start of the event, and that during the event,
charging may be lost or secured, and RCS inventory can meet the 10 CFR
part 50, appendix R performance goal for 180 minutes. The licensee
further stated that analysis indicates that valve 2-CH-192 may not need
to be opened until 252 minutes into the event.
The licensee stated that fire barrier deviations that could allow
the spread of products of combustion of a fire to an adjacent area that
either serves as a travel path for OMAs or is an action location for an
OMA have been found to not adversely impact OMA travel paths or action
areas.
A.5.3 Equipment Functionality and Accessibility
The licensee stated that as part of the OMA validation process,
lighting, component labeling, accessibility of equipment, tools, keys,
flashlights, and other devices or supplies needed are verified to
ensure successful completion of the OMA.
The licensee stated that for each OMA, the current Millstone 2 10
CFR part 50, appendix R report indicates that Operator access is
assured by an alternate path, or access is not required until after the
fire has been suppressed. Where applicable, the licensee stated that
OMAs have sufficient emergency lighting units to provide for access to
the particular component and to perform the task.
A.5.4 Available Indications
Indicators and indication cables have been evaluated by the
licensee as part of the exemption request process. Where impacts to
indication have been identified, the licensee provided an alternate
method to obtain the needed indication(s).
A.5.5 Communications
The licensee stated that Operators are provided with dedicated
radio communication equipment and that the 10 CFR part 50, appendix R
communication system utilizes a portion of the Millstone 800 megahertz
(MHz) trunked radio system, which consists of 800 MHz portable radio
units, a CR base station transmitter, antennas, a main communication
console located inside the CR, and redundant repeaters. The licensee
also stated that the CR base station transmitter is provided to ensure
two-way voice communications with the CR, without affecting plant
safety systems that may have sensitive electronic equipment located in
the area, and the resulting design configuration ensures communications
capability for all 10 CFR part 50, appendix R fire scenarios.
A.5.6 Portable Equipment
The licensee stated that all equipment required to complete a
required action is included in a preventative maintenance program and
is also listed in the TRM, which identifies surveillances for the
equipment utilized in each OMA.
A.5.7 Personnel Protection Equipment
The licensee stated that there are no OMAs required in fire areas
identified in the exemption request that necessitate the use of self-
contained breathing apparatus. No fire areas necessitate reentry to the
area of fire origin.
A.5.8 Procedures and Training
The licensee stated that entry into its AOP for ``FIRE'' is at the
first indication of a fire from a panel alarm or report from the field
and if the fire is in a 10 CFR part 50, appendix R area, the shift is
directed to determine if a fire should be considered a fire subject to
10 CFR part 50, appendix R (i.e., requiring use of the appendix R AOPs)
by:
1. Identifying actual or imminent damage to safe shutdown
components, switchgear, motor control centers, cable trays, or conduit
runs;
2. Observation of spurious operation of plant components needed for
safe shutdown;
3. Observation of loss of indication, control, or function of safe
shutdown plant systems or components;
4. Observation of conflicting instrument indication for safe
shutdown systems or components; or
5. Observation of parameters associated with safe shutdown systems
or components not being within expected limits for the existing plant
configuration.
The licensee stated that its AOP for ``FIRE'' has various
attachments that have 10 CFR part 50, appendix R egress/access routes
that provide a safe pathway to reach the required equipment necessary
to complete the
[[Page 49868]]
OMAs and that it has confirmed that the pathways will be free of
hazards to the Operators due to the subject fire.
The licensee also stated that there is a 10 CFR part 50, appendix R
AOP corresponding to each appendix R fire area, which is entered when
an appendix R fire is declared, and that Operations personnel train to
those AOPs, which identify the steps to perform each OMA. The licensee
further stated that time-critical OMAs are also identified within
operating procedures, which require that Operations personnel train to
perform these time-critical activities and that the OMAs presented in
this exemption request are encompassed in the time-critical procedure.
The licensee further stated that Operations personnel train to
these procedures and the AOPs identify the steps to perform each OMA.
The licensee further stated that the times allotted to perform these
tasks are easily achieved by experienced and inexperienced Operators
during training sessions, evaluated requalification training, and
supervised walkdowns, and that for each case, there is sufficient
margin to account for the uncertainties associated with stress,
environmental factors, and unexpected delays.
A.5.9 Staffing
The licensee stated that the Operations shift staffing requirements
include one additional licensed or non-licensed Operator over the
minimum technical specification requirement to be on duty each shift
during Modes 1, 2, 3, or 4, and that this Operator is designated as the
10 CFR part 50, appendix R Operator and is specified in the TRM. The
licensee also stated that the number of individuals available to
respond to the OMAs is one RO, two PEOs, and one additional licensed or
non-licensed individual (10 CFR part 50, appendix R Operator). The
licensee stated that the exemption request allocated tasks to PEO-1,
PEO-2, PEO-3, and RO-1, and that one of the three PEOs would be the TRM
required 10 CFR part 50, appendix R Operator, and with the exception of
the panel C10 activities, the assignments are interchangeable between
the four Operators, and since these individuals are specified by the
technical specification and TRM, they are not members of the fire
brigade and have no other collateral duties.
The licensee stated that Millstone 2 has a station emergency
response organization (SERO) and appropriate emergency response
facilities, and that declaration of an ALERT (events that are in
progress or have occurred and involving an actual or potential
substantial degradation of the level of safety of the plant, with
releases expected to be limited to small fractions of the Environmental
Protection Agency Protective Action Guideline exposure levels)
activates the SERO organization, which is immediately staffed by on-
site personnel and is fully established with on-call personnel within
60 minutes of the ALERT being declared. The licensee also stated that
after this time, off-shift Operations staff (e.g., personnel in
training, performing administrative functions, etc.) may be called in
as requested by the Shift Manager. The licensee further stated that
many of the OMAs are not required prior to the establishment of SERO
and that the additional staff available through SERO will improve the
reliability of these OMAs.
The licensee stated that Operators are required and assumed to be
within the protected area and that the time lines account for the
initial response by the field Operator. The licensee also stated that
upon the announcement of a fire, the field Operators are directed to
report to the CR and await further directions and that initially, upon
a report of a fire, the CR Operators enter their AOP for ``FIRE.'' The
licensee further stated that the flow path to get into a 10 CFR part
50, appendix R fire scenario is that upon indication of a fire the fire
brigade is dispatched and, based on the report or indications in the
CR, an appendix R fire may be declared, and in the development of the
time lines, the Operators are allowed 5 minutes to respond and report
to the CR.
A.5.10 Demonstrations
The licensee provided its validation process for the OMAs included
in the exemption request. The validation process included the
following: (1) Validation objectives, (2) validation frequency, (3)
validation methods, (4) validation attributes, and (5) validation
performance.
The licensee stated that all OMAs are encompassed in its operating
procedures and that an enhancement to the tracking and training on
time-critical activities has been developed and is currently being
implemented.
The licensee stated that all of the OMAs identified are contained
in the AOPs to respond to a 10 CFR part 50, appendix R fire and that
during initial validation of these procedures, the OMAs were performed,
and all of the time performance objectives were met as a result of the
validation.
A.5.11 Feasibility Summary
The licensee's analysis demonstrates that, for the expected
scenarios, the OMAs can be diagnosed and executed within the amount of
time available to complete them. The licensee's analysis also
demonstrates that various factors, including the factor of two times
margin, the use of the minimum BAST inventory, and the use of the CST
inventory, have been considered to address uncertainties in estimating
the time available. Therefore, the OMAs included in this review are
feasible because there is adequate time available for the Operator to
perform the required OMAs to achieve and maintain hot shutdown
following a postulated fire event. Where a diagnosis time has been
identified, it is included as part of the required time for a
particular action. Where an action has multiple times or contingencies
associated with the ``allowable'' completion time, the lesser time is
used. This approach is considered to represent a conservative approach
to analyzing the timelines associated with each of the OMAs with regard
to the feasibility and reliability of the actions included in this
exemption. All OMAs have at least 30 minutes of margin. Margin is based
on using the most limiting information from the licensee; for example,
if the licensee postulated a range of time for diagnosis, the required
time includes the largest number in the range.
The completion times indicate reasonable assurance that the OMAs
can reliably be performed under a wide range of conceivable conditions
by different plant crews because it, in conjunction with the time
margins associated with each action and other installed fire protection
features, accounts for sources of uncertainty such as variations in
fire and plant conditions, factors unable to be recreated in
demonstrations and human-centered factors.
Finally, these numbers should not be considered without the
understanding that the manual actions are a fallback, in the unlikely
event that the fire protection DID features are insufficient. In most
cases, there is no credible fire scenario that would necessitate the
performance of these OMAs. The licensee provided a discussion of the
activity completion times and associate margins related to the OMAs.
A.5.12 Reliability
A reliable action is a feasible action that is analyzed and
demonstrated as being dependably repeatable within an available time.
The above criteria, Sections 3.5.1 through 3.5.10, provide
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the NRC staff's basis that the actions are feasible. Section 3.5.11
provides a discussion of the available time margin. The licensee
provided a basis that the actions were reliable based on the available
time margin; the administrative controls such as procedures, staffing
levels, and availability of equipment; and by accounting for
uncertainty in fires and plant conditions. Therefore, the OMAs included
in this review are reliable because there is adequate time available to
account for uncertainties not only in estimates of the time available,
but also in estimates of how long it takes to diagnose a fire and
execute the OMAs (e.g., as based, at least in part, on a plant
demonstration of the actions under non-fire conditions). For example,
OMA 1 establishes the RWST as the suction supply for the charging
system and is not conducted until after AFW is established. Further,
since the BASTs have a minimum TRM specified inventory to ensure 72
minutes of flow, OMA 1 can be completed with 40 minutes of margin.
A.6 Summary of DID and Operator Manual Actions
In summary, the DID concept for a fire in the fire areas discussed
above provides a level of safety that results in the unlikely
occurrence of fires, rapid detection, control, and extinguishment of
fires that do occur and the protection of SSCs important to safety. As
discussed above, the licensee has provided preventative and protective
measures in addition to feasible and reliable OMAs that, together,
demonstrate the licensee's ability to preserve or maintain safe
shutdown capability in the event of a fire in the analyzed fire areas.
B. Authorized by Law
This exemption would allow Millstone 2 to rely on OMAs, in
conjunction with the other installed fire protection features, to
ensure that at least one means of achieving and maintaining hot
shutdown remains available during and following a postulated fire event
as part of its fire protection program, in lieu of meeting the
requirements specified in 10 CFR part 50, appendix R, section III.G.2,
for a fire in the analyzed fire areas. As stated above, Sec. 50.12
allows the NRC to grant exemptions from the requirements of 10 CFR part
50. The NRC staff has determined that granting of this exemption will
not result in a violation of the Atomic Energy Act of 1954, as amended,
or the Commission's regulations. Therefore, the exemption is authorized
by law.
C. No Undue Risk to Public Health and Safety
The underlying purpose of 10 CFR part 50, appendix R, section
III.G, is to ensure that at least one means of achieving and
maintaining hot shutdown remains available during and following a
postulated fire event. Based on the above, no new accident precursors
are created by the use of the specific OMAs, in conjunction with the
other installed fire protection features, in response to a fire in the
analyzed fire areas. Therefore, the probability of postulated accidents
is not increased. Also, based on the above, the consequences of
postulated accidents are not increased. Therefore, there is no undue
risk to public health and safety.
D. Consistent With the Common Defense and Security
This exemption would allow Millstone 2 to credit the use of the
specific OMAs, in conjunction with the other installed fire protection
features, in response to a fire in the analyzed fire areas discussed
above, in lieu of meeting the requirements specified in 10 CFR part 50,
appendix R, section III.G.2. This change, to the operation of the
plant, has no relation to security issues. Therefore, the common
defense and security is not diminished by this exemption.
E. Special Circumstances
One of the special circumstances described in Sec. 50.12(a)(2)(ii)
is that the application of the regulation is not necessary to achieve
the underlying purpose of the rule. The underlying purpose of 10 CFR
part 50, appendix R, section III.G, is to ensure that at least one
means of achieving and maintaining hot shutdown remains available
during and following a postulated fire event. While the licensee does
not comply with the explicit requirements of 10 CFR part 50, appendix
R, section III.G.2, specifically, it does meet the underlying purpose
of section III.G as a whole by ensuring that safe shutdown capability
remains available through the combination of DID and OMAs. Therefore,
special circumstances exist that warrant the issuance of this exemption
as required by Sec. 50.12(a)(2)(ii).
IV. Conclusion
Based on the all of the features of the DID concept discussed
above, the NRC staff concludes that the use of the requested OMAs, in
these particular instances and in conjunction with the other installed
fire protection features, in lieu of strict compliance with the
requirements of 10 CFR part 50, appendix R, section III.G.2, is
consistent with the underlying purpose of the rule. As such, the level
of safety present at Millstone 2 is commensurate with the established
safety standards for nuclear power plants.
Accordingly, the Commission has determined that, pursuant to Sec.
50.12(a), the exemption is authorized by law, will not present an undue
risk to the public health and safety, is consistent with the common
defense and security and that special circumstances are present to
warrant issuance of the exemption. Therefore, the Commission hereby
grants Dominion an exemption from the requirements of 10 CFR part 50,
appendix R, section III.G.2, to utilize the OMAs discussed above at
Millstone 2.
Pursuant to Sec. 51.32, an environmental assessment and finding of
no significant impact related to this exemption was published in the
Federal Register on September 28, 2017 (82 FR 45322). Based upon the
environmental assessment, the Commission has determined that the
granting of this exemption will not have a significant effect on the
quality of the human environment.
This exemption is effective upon issuance of this Federal Register
notice.
Dated at Rockville, Maryland, this 24th day of October, 2017.
For the Nuclear Regulatory Commission.
Eric J. Benner,
Deputy Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. 2017-23427 Filed 10-26-17; 8:45 am]
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