[Federal Register Volume 68, Number 121 (Tuesday, June 24, 2003)]
[Notices]
[Pages 37590-37593]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-15860]
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NUCLEAR REGULATORY COMMISSION
Notice of Opportunity To Comment on Model Safety Evaluation on
Technical Specification Improvement Regarding Extension of Reactor
Coolant Pump Motor Flywheel Examination for Westinghouse Plants Using
the Consolidated Line Item Improvement Process
AGENCY: Nuclear Regulatory Commission.
ACTION: Request for comment.
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SUMMARY: Notice is hereby given that the staff of the Nuclear
Regulatory Commission (NRC) has prepared a model safety evaluation (SE)
relating to a change in the technical specification
[[Page 37591]]
(TS) required inspection interval for reactor coolant pump (RCP)
flywheels at Westinghouse-designed reactors. This change was proposed
for incorporation into the Standard Technical Specifications (STS) for
Westinghouse Plants (NUREG-1431) by the Westinghouse Owners Group (WOG)
participants in the Nuclear Energy Institute's Technical Specification
Task Force (TSTF), and is designated as TSTF-421, Revision 0. The
proposed change to the TS would extend the RCP motor flywheel
examination frequency from the currently approved 10-year inspection
interval, to an interval not to exceed 20 years. The allowed extension
in the inspection interval would allow licensees to improve their
coordination of the flywheel examination with planned RCP
refurbishments. The NRC staff has also prepared a model no significant
hazards consideration (NSHC) determination relating to this matter. The
purpose of this model is to permit the NRC to efficiently process
amendments that propose to incorporate this change into plant-specific
TSs. Licensees of nuclear power reactors to which the models apply
could request amendments confirming the applicability of the SE and
NSHC determination to their reactors. The NRC staff is requesting
comments on the model SE and model NSHC determination prior to
announcing their availability for referencing in license amendment
applications.
DATES: The comment period expires July 24, 2003. 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: William Reckley, Mail Stop: O-7D1,
Division of Licensing Project Management, Office of Nuclear Reactor
Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001, telephone 301-415-1323.
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. This is accomplished
by processing proposed changes to the STS in a manner that supports
subsequent license amendment applications. The CLIIP includes an
opportunity for the public to comment on proposed changes to the STS
following a preliminary assessment by the NRC staff and finding that
the change will likely be offered for adoption by licensees. This
notice is soliciting comment on a proposed change to the STS that
extends the inspection interval for RCP flywheels from 10 years to 20
years. 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 to proceed with announcing the availability of the change for
proposed adoption by licensees. Those licensees opting to apply for the
subject change to TSs 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 would be
processed and noticed in accordance with applicable rules and NRC
procedures.
This notice involves changes to extend the inspection interval for
RCP flywheels for those plants with Westinghouse designs. This proposed
change was proposed for incorporation into the STS by the WOG as TSTF-
421, Revision 0. Much of the technical support for TSTF-421, Revision
0, was provided in topical report WCAP-15666, Revision 0, ``Extension
of Reactor Coolant Pump Motor Flywheel Examination,'' submitted on
August 24, 2001. The NRC staff's acceptance of the topical report is
documented in an SE dated May 5, 2003, which is accessible
electronically from the Agencywide Documents Access and Management
System's (ADAMS) Public Electronic Reading Room on the Internet at the
NRC Web site, http://www.nrc.gov/reading-rm/adams.html (ADAMS Accession
No. ML031250595). Persons who do not have access to ADAMS or who
encounter problems in accessing the documents located in ADAMS, should
contact the NRC PDR Reference staff by telephone at 1-800-397-4209,
301-415-4737, or by e-mail to [email protected].
Applicability
This proposed change to the inspection interval for RCP motor
flywheels is applicable to plants with Westinghouse-designed nuclear
steam supply systems. The CLIIP does not prevent licensees from
requesting an alternative approach or proposing changes other than
those proposed in TSTF-421. Variations from the approach recommended in
this notice may, however, require additional review by the NRC staff
and may increase the time and resources needed for the review.
Public Notices
This notice requests comments from interested members of the public
within 30 days of the date of publication in the Federal Register.
Following the staff's evaluation of comments received as a result of
this notice, the staff may reconsider the proposed change or may
proceed with announcing the availability of the change in a subsequent
notice (perhaps with some changes to the SE or proposed NSHC
determination as a result of public comments). If the staff announces
the availability of the change, licensees wishing to adopt the change
will submit an application in accordance with applicable rules and
other regulatory requirements. The staff will in turn issue for each
application a notice of consideration of issuance of amendment to
facility operating license(s), a proposed NSHC determination, and an
opportunity for a hearing. A notice of issuance of an amendment to
operating license(s) will also be issued to announce the revised
requirements for each plant that applies for and receives the requested
change.
Proposed Safety Evaluation: U.S. Nuclear Regulatory Commission, Office
of Nuclear Reactor Regulation, Consolidated Line Item Improvement,
Technical Specification Task Force (TSTF) Change TSTF-421, Extension of
Reactor Coolant Pump Motor Flywheel Examinations
1.0 Introduction
By application dated [ ], [Licensee] (the licensee) requested
changes to the Technical Specifications (TSs) for [facility]. The
proposed changes would extend the reactor coolant pump (RCP)
[[Page 37592]]
motor flywheel examination frequency from the currently approved 10-
year inspection interval to an interval not to exceed 20 years. These
changes are based on Technical Specification Task Force (TSTF) change
traveler TSTF-421 (Revision 0) that has been approved generically for
the Westinghouse Standard Technical Specifications (STS), NUREG-1431. A
notice announcing the availability of this proposed TS change using the
consolidated line item improvement process (CLIIP) was published in the
Federal Register on [ ] (xx FR yyyyy).
2.0 Regulatory Evaluation
The function of the RCP in the reactor coolant system (RCS) of a
pressurized water reactor plant is to maintain an adequate cooling flow
rate by circulating a large volume of primary coolant water at high
temperature and pressure through the RCS. Following an assumed loss of
power to the RCP motor, the flywheel, in conjunction with the impeller
and motor assembly, provides sufficient rotational inertia to assure
adequate primary coolant flow during RCP coastdown, thus resulting in
adequate core cooling. A concern regarding the overspeed of the RCP and
its potential for failure led to the issuance of Regulatory Guide (RG)
1.14, ``Reactor Coolant Pump Flywheel Integrity,'' Revision 1, dated
August 1975. RG 1.14 describes a method acceptable to the NRC staff of
addressing concerns related to RCP vibration and the possible effects
of missiles that might result from the failure of the RCP flywheel. The
need to protect components important to safety from such missiles are
included in General Design Criterion 4, ``Environmental and Dynamic
Effects Design Basis,'' of Appendix A, ``General Design Criteria for
Nuclear Power Plants,'' to 10 CFR Part 50, ``Licensing of Production
and Utilization Facilities,'' which is applicable to plants that
obtained their construction permits after May 21, 1971.
Specific requirements to have an RCP Flywheel Inspection Program
consistent with RG 1.14 or previously issued relaxations from the RG
are included in the Administrative Controls Section of the TSs. The
purpose of the testing and inspection programs defined in the TSs is to
ensure that the probability of a flywheel failure is sufficiently small
such that additional safety features are not needed to protect against
a flywheel failure. The RG provides criteria in terms of critical
speeds that could result in the failure of a RCP flywheel during normal
or accident conditions. In addition to the guidance in RG 1.14, the NRC
has more recently issued RG 1.174, ``An Approach for Using
Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-
Specific Changes to the Licensing Basis,'' which provides guidance and
criteria for evaluating proposed changes that use risk-informed
justifications.
A proposed justification for extending the RCP flywheel inspections
from a 10-year inspection interval to an interval not to exceed 20
years was provided by the Westinghouse Owners Group (WOG) in topical
report WCAP-15666, ``Extension of Reactor Coolant Pump Motor Flywheel
Examination,'' transmitted by letter dated August 24, 2001. The topical
report addressed the proposed extension for all domestic WOG plants.
The NRC accepted the topical report for referencing in license
applications in a letter and safety evaluation dated May 5, 2003 (ADAMS
Accession No. ML031250595).
3.0 Technical Evaluation
TS [5.5.7], Reactor Coolant Pump Flywheel Inspection Program,
reflects the licensee's previous adoption of a TS change that defined
the allowable alternative to the inspections described in RG 1.14. The
inspections are defined as in-place ultrasonic examination over the
volume from the inner bore of the flywheel to the circle of one-half
the outer radius or an alternative surface examination (magnetic
particle testing [MT] and/or liquid penetrant testing [PT]) of exposed
surfaces defined by the volume of the disassembled flywheel. The
allowable interval for these inspections was extended in the previous
amendment to ``approximately 10 year intervals coinciding with the
Inservice Inspection schedule as required by ASME [American Society of
Mechanical Engineers, Boiler and Pressure Vessel Code,] Section XI.''
The change proposed in this amendment application would revise the
allowable inspection interval to ``20 year intervals.''
The justification for the proposed change was provided in WCAP-
15666, which the staff accepted for referencing in license applications
by a letter and safety evaluation dated May 5, 2003. The topical report
addresses the three critical speeds defined in RG 1.14: (a) the
critical speed for ductile failure, (b) the critical speed for non-
ductile failure, and (c) the critical speed for excessive deformation
of the flywheel. The staff found that the topical report adequately
addressed these issues and demonstrated that acceptance criteria, for
normal and accident conditions defined in RG 1.14, would continue to be
met for all domestic WOG plants following an extension of the
inspection interval. The topical report also provided a risk assessment
for extending the RCP flywheel inspection interval. The staff's review,
documented in the SE for the topical report, determined that the
analysis methods and risk estimates are acceptable when compared to the
guidance in RG 1.174.
In conclusion, the staff finds that the regulatory positions in RG
1.14 concerning the three critical speeds are satisfied, and that the
evaluation indicating that critical crack sizes are not expected to be
attained during a 20-year inspection interval is reasonable and
acceptable. The potential for failure of the RCP flywheel is, and will
continue to be, negligible during normal and accident conditions. The
change is therefore acceptable.
4.0 State Consultation
In accordance with the Commission's regulations, the [State] State
official was notified of the proposed issuance of the amendments. The
State official had [choose one: (1) no comments, or (2) the following
comments--with subsequent disposition by the staff].
5.0 Environmental Consideration
The amendment changes a requirement with respect to the
installation or use of a facility component located within the
restricted area as defined in 10 CFR part 20 and changes surveillance
requirements. 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. The Commission has previously issued a proposed
finding that the amendment involves no significant hazards
consideration, and there has been no public comment on such finding (xx
FR xxxxx). Accordingly, the amendment meets the eligibility criteria
for categorical exclusion set forth in 10 CFR 51.22(c)(9). 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, based on 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
[[Page 37593]]
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.
Proposed No Significant Hazards Consideration Determination
Description of Amendment Request: The proposed amendment revises TS
[5.5.7, ``Reactor Coolant Pump Flywheel Inspection Program,''] to
extend the allowable inspection interval to 20 years.
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 to the RCP flywheel examination frequency does
not change the response of the plant to any accidents. The RCP will
remain highly reliable and the proposed change will not result in a
significant increase in the risk of plant operation. Given the
extremely low failure probabilities for the RCP motor flywheel during
normal and accident conditions, the extremely low probability of a
loss-of-coolant accident (LOCA) with loss of offsite power (LOOP), and
assuming a conditional core damage probability (CCDP) of 1.0 (complete
failure of safety systems), the core damage frequency (CDF) and change
in risk would still not exceed the NRC's acceptance guidelines contined
in RG 1.174 (<1.0E-6 per year). Moreover, considering the uncertainties
involved in this evaluation, the risk associated with the postulated
failure of an RCP motor flywheel is significantly low. Even if all four
RCP motor flywheels are considered in the bounding plant configuration
case, the risk is still acceptably low.
The proposed change does not adversely affect accident initiators
or precursors, nor alter the design assumptions, conditions, or
configuration of the facility, or the manner in which the plant is
operated and maintained; alter or prevent the ability of structures,
systems, components (SSCs) from performing their intended function to
mitigate the consequences of an initiating event within the assumed
acceptance limits; or affect the source term, containment isolation, or
radiological release assumptions used in evaluating the radiological
consequences of an accident previously evaluated. Further, the proposed
change does not increase the type or amount of radioactive effluent
that may be released offsite, nor significantly increase individual or
cumulative occupational/public radiation exposure. The proposed change
is consistent with the safety analysis assumptions and resultant
consequences. Therefore, the proposed 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 Accident Previously
Evaluated
The proposed change in flywheel inspection frequency does not
involve any change in the design or operation of the RCP. Nor does the
change to examination frequency affect any existing accident scenarios,
or create any new or different accident scenarios. Further, the change
does not involve a physical alteration of the plant (i.e., no new or
different type of equipment will be installed) or alter the methods
governing normal plant operation. In addition, the change does not
impose any new or different requirements or eliminate any existing
requirements, and does not alter any assumptions made in the safety
analysis. The proposed change is consistent with the safety analysis
assumptions and current plant operating practice. Therefore, the
proposed change does not create the possibility of a new or different
kind of accident from any accident previously evaluated.
Criterion 3--The Proposed Change Does Not Involve a Significant
Reduction in a Margin of Safety
The proposed change does not alter the manner in which safety
limits, limiting safety system settings, or limiting conditions for
operation are determined. The safety analysis acceptance criteria are
not impacted by this change. The proposed change will not result in
plant operation in a configuration outside of the design basis. The
calculated impact on risk is insignificant and meets the acceptance
criteria contained in RG 1.174. There are no significant mechanisms for
inservice degradation of the RCP flywheel. Therefore, the proposed
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 in Rockville, Maryland, this 13th day of June, 2003.
For the Nuclear Regulatory Commission.
Robert A. Gramm,
Acting Director, Project Directorate IV, Division of Licensing Project
Management, Office of Nuclear Reactor Regulation.
[FR Doc. 03-15860 Filed 6-23-03; 8:45 am]
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