ML020220399
| ML020220399 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 03/19/2002 |
| From: | Thadani M NRC/NRR/DLPM/LPD4 |
| To: | Cottle W South Texas |
| References | |
| TAC MB2138, TAC MB2139, TS 3.3.1, TS 3.3.2 | |
| Download: ML020220399 (14) | |
Text
March 19, 2002 Mr. William T. Cottle President and Chief Executive Officer STP Nuclear Operating Company South Texas Project Electric Generating Station P. O. Box 289 Wadsworth, TX 77483
SUBJECT:
SOUTH TEXAS PROJECT, UNITS 1 AND 2 - ISSUANCE OF AMENDMENTS REVISING ALLOWABLE OUTAGE TIMES AND BYPASS TEST TIMES FOR INSTRUMENTATION (TAC NOS. MB2138 AND MB2139)
Dear Mr. Cottle:
The Commission has issued the enclosed Amendment No. 136 to Facility Operating License No. NPF-76 and Amendment No. 125 to Facility Operating License No. NPF-80 for the South Texas Project, Units 1 and 2, respectively. The amendments consist of changes to the Technical Specifications (TSs) in response to your application dated May 30, 2001.
The amendments permit relaxation of the allowed outage times and bypass test times for limiting conditions of operation specified in TSs 3.3.1, "Reactor Trip System Instrumentation,"
and 3.3.2, "Engineered Safety Features Actuation System Instrumentation." The licensee has provided changes to Bases pages, which have been incorporated.
A copy of our related Safety Evaluation is enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.
Sincerely,
/RA/
Mohan C. Thadani, Senior Project Manager, Section 1 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosures:
- 1. Amendment No. 136 to NPF-76
- 2. Amendment No. 125 to NPF-80
- 3. Safety Evaluation cc w/encls: See next page
March 19, 2002 Mr. William T. Cottle President and Chief Executive Officer STP Nuclear Operating Company South Texas Project Electric Generating Station P. O. Box 289 Wadsworth, TX 77483
SUBJECT:
SOUTH TEXAS PROJECT, UNITS 1 AND 2 - ISSUANCE OF AMENDMENTS REVISING ALLOWABLE OUTAGE TIMES AND BYPASS TEST TIMES FOR INSTRUMENTATION (TAC NOS. MB2138 AND MB2139)
Dear Mr. Cottle:
The Commission has issued the enclosed Amendment No. 136 to Facility Operating License No. NPF-76 and Amendment No. 125 to Facility Operating License No. NPF-80 for the South Texas Project, Units 1 and 2, respectively. The amendments consist of changes to the Technical Specifications (TSs) in response to your application dated May 30, 2001.
The amendments permit relaxation of the allowed outage times and bypass test times for limiting conditions of operation specified in TSs 3.3.1, "Reactor Trip System Instrumentation,"
and 3.3.2, "Engineered Safety Features Actuation System Instrumentation." The licensee has provided changes to Bases pages, which have been incorporated.
A copy of our related Safety Evaluation is enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.
Sincerely,
/RA/
Mohan C. Thadani, Senior Project Manager, Section 1 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosures:
- 1. Amendment No. 136 to NPF-76
- 2. Amendment No. 125 to NPF-80
- 3. Safety Evaluation cc w/encls: See next page DISTRIBUTION: RidsNrrDlpmLpdiv1 (RGramm)
PUBLIC RidsNrrDripRorp (R.Dennig)
PDIV-1 r/f RidsNrrLAMMcAllister G. Hill (4) RidsAcrsAcnwMailCenter RidsNrrDlpmLpdiv (S.Richards) RidsOgcRp RidsNrrPMMThadani S. Athavale RidsRgn4MailCenter (D. Graves, L. Hurley, D. Bujol)
ACCESSION NO: ML020220399 OFFICE PDIV-1/PM PDIV-1/LA EEIB-BC* SPSB/BC OGC PDIV-1/SC NAME MThadani MmcAllister CGrimes RHoefling RGramm DATE 3/7/02 2/15/02 11/01/01 3/14/02 3/14/02 3/15/02 OFFICIAL RECORD COPY
South Texas, Units 1 & 2 cc:
Mr. Cornelius F. OKeefe A. H. Gutterman, Esq.
Senior Resident Inspector Morgan, Lewis & Bockius U.S. Nuclear Regulatory Commission 1111 Pennsylvania Avenue, NW P. O. Box 910 Washington, DC 20004 Bay City, TX 77414 Mr. J. J. Sheppard, Vice President A. Ramirez/C. M. Canady Engineering & Technical Services City of Austin STP Nuclear Operating Company Electric Utility Department P. O. Box 289 721 Barton Springs Road Wadsworth, TX 77483 Austin, TX 78704 S. M. Head, Manager, Licensing Mr. M. T. Hardt Nuclear Quality & Licensing Department Mr. W. C. Gunst STP Nuclear Operating Company City Public Service Board P. O. Box 289, Mail Code: N5014 P. O. Box 1771 Wadsworth, TX 77483 San Antonio, TX 78296 Office of the Governor Mr. C. A. Johnson/R. P. Powers ATTN: John Howard, Director AEP - Central Power and Light Company Environmental and Natural P. O. Box 289 Resources Policy Mail Code: N5022 P. O. Box 12428 Wadsworth, TX 77483 Austin, TX 78711 INPO Jon C. Wood Records Center Matthews & Branscomb 700 Galleria Parkway 112 East Pecan, Suite 1100 Atlanta, GA 30339-3064 San Antonio, TX 78205 Regional Administrator, Region IV Arthur C. Tate, Director U.S. Nuclear Regulatory Commission Division of Compliance & Inspection 611 Ryan Plaza Drive, Suite 400 Bureau of Radiation Control Arlington, TX 76011 Texas Department of Health 1100 West 49th Street D. G. Tees/R. L. Balcom Austin, TX 78756 Houston Lighting & Power Co.
P. O. Box 1700 Jim Calloway Houston, TX 77251 Public Utility Commission of Texas Electric Industry Analysis Judge, Matagorda County P. O. Box 13326 Matagorda County Courthouse Austin, TX 78711-3326 1700 Seventh Street Bay City, TX 77414 February 2002
STP NUCLEAR OPERATING COMPANY DOCKET NO. 50-498 SOUTH TEXAS PROJECT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 136 License No. NPF-76
- 1. The Nuclear Regulatory Commission (the Commission) has found that:
A. The application for amendment by STP Nuclear Operating Company* acting on behalf of itself and for Houston Lighting & Power Company (HL&P), the City Public Service Board of San Antonio (CPS), Central Power and Light Company (CPL), and the City of Austin, Texas (COA) (the licensees), dated May 30, 2001, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, as amended, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this license amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
- STP Nuclear Operating Company is authorized to act for Houston Lighting & Power Company (HL&P), the City Public Service Board of San Antonio, Central Power and Light Company, and the City of Austin, Texas, and has exclusive responsibility and control over the physical construction, operation, and maintenance of the facility.
- 2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment and Paragraph 2.C.(2) of Facility Operating License No. NPF-76 is hereby amended to read as follows:
(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 136, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. The South Texas Project Nuclear Operating Company shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
- 3. The license amendment is effective as of its date of issuance and shall be implemented within 30 days from the date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Robert A. Gramm, Chief, Section 1 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance: March 19, 2002
STP NUCLEAR OPERATING COMPANY DOCKET NO. 50-499 SOUTH TEXAS PROJECT, UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 125 License No. NPF-80
- 1. The Nuclear Regulatory Commission (the Commission) has found that:
A. The application for amendment by STP Nuclear Operating Company* acting on behalf of itself and for Houston Lighting & Power Company (HL&P), the City Public Service Board of San Antonio (CPS), Central Power and Light Company (CPL), and the City of Austin, Texas (COA) (the licensees), dated May 30, 2001, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, as amended, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this license amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
- STP Nuclear Operating Company is authorized to act for Houston Lighting & Power Company (HL&P), the City Public Service Board of San Antonio, Central Power and Light Company, and the City of Austin, Texas, and has exclusive responsibility and control over the physical construction, operation, and maintenance of the facility.
- 2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment and Paragraph 2.C.(2) of Facility Operating License No. NPF-80 is hereby amended to read as follows:
(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 125, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. The South Texas Project Nuclear Operating Company shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
- 3. The license amendment is effective as of its date of issuance and shall be implemented within 30 days from the date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Robert A. Gramm, Chief, Section 1 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance: March 19, 2002
ATTACHMENT TO LICENSE AMENDMENT NOS. 136 AND 125 FACILITY OPERATING LICENSE NOS. NPF-76 AND NPF-80 DOCKET NOS. 50-498 AND 50-499 Replace the following pages of the Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.
REMOVE INSERT 3/4 3-3 3/4 3-3 3/4 3-4 3/4 3-4 3/4 3-5 3/4 3-5 3/4 3-6 3/4 3-6 3/4 3-7 3/4 3-7 3/4 3-8 3/4 3-8 3/4 3-11 3/4 3-11 3/4 3-12 3/4 3-12 3/4 3-13 3/4 3-13 3/4 3-15 3/4 3-15 3/4 3-18 3/4 3-18 3/4 3-21 3/4 3-21 3/4 3-26 3/4 3-26 3/4 3-27 3/4 3-27 3/4 3-28 3/4 3-28 3/4 3-42 3/4 3-42 3/4 3-43 3/4 3-43 3/4 3-44 3/4 3-44 3/4 3-45 3/4 3-45 3/4 3-46 3/4 3-46 3/4 3-47 3/4 3-47 3/4 3-48 3/4 3-48 3/4 3-49 3/4 3-49
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 136 AND 125 TO FACILITY OPERATING LICENSE NOS. NPF-76 AND NPF-80 STP NUCLEAR OPERATING COMPANY, ET AL.
SOUTH TEXAS PROJECT, UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499
1.0 INTRODUCTION
By application dated May 30, 2001, STP Nuclear Operating Company (the licensee), requested changes to the South Texas Project (STP), Units 1 and 2, Technical Specifications (TSs). The proposed changes would amend operating licenses NPF-76 and NPF-80. The proposed amendments relax the TS requirements for the allowed outage times (AOTs) and bypass test times (BTTs) for Limiting Condition for Operation (LCO) 3.3.1, Reactor Trip System (RTS)
Instrumentation, and LCO 3.3.2, Engineered Safety Features Actuation System (ESFAS)
Instrumentation. In addition, the amendments revise the test interval for solid state protection system (SSPS) input relays to once every 18 months (i.e., at refueling outage), make a few administrative, editorial, and format changes, and revise the corresponding Bases sections.
The proposed AOT and BTT relaxation is in accordance with the requirements of Westinghouse Owners Group (WOG) Topical Report WCAP-14333-P-A, Revision 1, Probabilistic Risk Analysis of the RPS [Reactor Protection System] and ESFAS Test Times and Completion Times.
The proposed AOT and BTT extensions are in addition to the extensions that were previously approved by the NRC staff in its safety evaluation reports (SERs) for WOG Topical Report WCAP-10271-P-A and the associated Supplement 1, Evaluation of Surveillance Frequencies and Out of Service Times for Reactor Protection Instrumentation System, and Topical Report WCAP-10271-P-A and Supplement 2 , Revision 1, Evaluation of Surveillance Frequencies and Out of Service Times for the Engineered Safety Features Actuation System. In its submittal the licensee states that the impact of the proposed extended AOTs and BTTs will result in an overall improvement in safety by reducing the potential for spurious reactor trips and spurious activation of safety equipment. The longer AOTs and BTTs will provide additional time before the associated channel must be placed in trip. As a part of the implementation of the proposed license amendment, the licensee will add SSPS train and ESFAS train unavailability to its Configuration Risk Management Program (CRMP).
To facilitate testing in bypass, the licensee proposes to implement certain design and hardware changes to the nuclear instrumentation system (NIS) and the 7300 process protection system
(PPS). The hardware modifications will be performed in accordance with the requirements of Section 50.59 of Title 10 of the Code of Federal Regulations (10 CFR 50.59).
2.0 BACKGROUND
Operating plants have experienced inadvertent trips and safeguards actuations during the performance of instrumentation surveillance, causing unnecessary transients and challenges to safety systems. In response to these concerns, WOG initiated a program to develop a justification for revising generic and plant-specific instrumentation TS to allow testing-in-bypass.
WOG evaluated the significance of testing in bypass, rather than with a partial trip and extending surveillance test intervals (STIs) and AOTs, and determined that both could be done without compromising plant safety.
In 1983, the WOG published the results of its study and proposals for remedial actions in WCAP-10271. This document was later revised several times in response to NRCs comments.
The NRC staff issued SERs and a supplemental SER (SSER) for WCAP-10271 and its supplements during 1989 and 1990. The SERs approved quarterly testing, increased the time for placing an inoperable channel in a tripped mode to 6 hours0.25 days <br />0.0357 weeks <br />0.00822 months <br />, and increased AOTs for testing in bypass from 2 to 4 hours0.167 days <br />0.0238 weeks <br />0.00548 months <br />. In its submittal, the licensee states that all of these relaxations have been implemented at STP, Units 1 and 2. In addition, the NRC staffs SERs approved testing in bypass for analog channels and increased the AOT for an inoperable actuation-logic and relay channel from 1 to 6 hours0.25 days <br />0.0357 weeks <br />0.00822 months <br />. In WCAP-10271 and its supplements, the WOG evaluated the impact of the revised STI, AOT, and bypass testing on core damage frequency (CDF) and the public risk. The NRC staff in its SER and SSER concluded that the overall upper bound of the CDF increased, due to proposed changes, is less than 6 percent for a Westinghouse pressurized water reactor. The NRC also concluded that actual CDF increase for individual plants would be substantially less than 6 percent and considered this increase to be small compared to the range of uncertainty in CDF analyses and; therefore, acceptable. In its submittal, the licensee states that the WOG program was based on a typical Westinghouse four-loop plant design similar to that of STP; therefore, the results are applicable to the STP, Units 1 and 2 analog channel changes.
WCAP-14333-P-A, Revision 1, Probabilistic Risk Analysis of the RPS and ESFAS Test Times and Completion Times, provides the technical basis and methodology for further extending the AOTs and BTTs listed in WCAP-10271. The report employs a risk-informed approach to justify further extensions. WCAP-14333-P-A assessed the impact of the proposed test time and AOT changes on CDF, incremental core damage probability, and large early release frequency.
The results of the risk evaluation demonstrated that the results conform to the acceptance guidelines in the NRC Regulatory Guide (RG) 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, and RG 1.177, An Approach for Plant-Specific, Risk-Informed Decision-making: Technical Specifications. The NRC SER for WCAP-14333-P-A concluded that the risk analysis in WCAP-14333-P-A support the proposed TS changes and is acceptable subject to the safety evaluation (SE) conditions which must be addressed in licensees plant-specific license amendment requests referencing WCAP-14333-P-A.
2.1 Proposed Changes The proposed changes will permit relaxation of the AOTs and BTTs for the instrumentation of LCO 3.3.1, RTS and LCO 3.3.2, ESFAS. Attachment 3 to the licensees license amendment request dated May 30, 2001, describes the proposed changes in detail, and Attachment 6 contains a marked up copy of the TS pages.
The following table summarizes the proposed changes.
Technical Specification Current Parameter Proposed Parameter RTS and ESFAS Instrumentation (analog channels)
S Bypass Test Time 4 hours0.167 days <br />0.0238 weeks <br />0.00548 months <br /> 12 hours0.5 days <br />0.0714 weeks <br />0.0164 months <br /> S Allowed Outage Time 1 or 6 hours0.25 days <br />0.0357 weeks <br />0.00822 months <br /> 72 hours3 days <br />0.429 weeks <br />0.0986 months <br /> S Automatic Actuation Current specs 24 hr allowed outage Logic and Actuation require shutdown time, followed by 6 hr.
Relays to Mode 3 within to shutdown to Mode 3 6 hr Note 19 is added to Table 4.3-1, on pages 3/4-3-11, 12, 13 and 15, and Note 7 is added to Table 4.3.2, on pages 3/4-3-43, 44, 45, 46, 47, 48, and 49 to clarify that the input relays of channels with bypass test instrumentation, will be tested on an 18-month frequency.
To allow testing in bypass without lifting leads or installing jumpers, certain design and hardware changes will be made to the NIS and PPS. In its submittal the licensee states that all required design and hardware changes will be implemented in accordance with the requirements of 10 CFR 50.59.
3.0 EVALUATION In accordance with the current TS requirements, all analog channels in the RTS and ESFAS except analog channels of the NIS and containment spray systems, are placed in the tripped state for channel testing or taken out of service. With an inoperable channel in the tripped state, maintenance or testing cannot be performed on a redundant channel unless one of the channels is bypassed. With one channel in a tripped condition, a trip in another channel caused by human error, a spurious transient, or channel failure would initiate a reactor trip and/or safeguards actuation.
WCAP-14333-P-A, Revision 1, provides the technical basis and methodology for extending AOTs and BTTs. In its submittal the licensee states that it used a risk-informed approach to justify AOT and BTT extensions, consistent with recommendations of RG 1.174, and RG 1.177.
As presented in RG 1.177, evaluation of the impact of the proposed revisions was performed using the three-tired approach. Tier 1, PRA Capability and Insights, assessed the impact on CDF, incremental conditional core damage probability, and large early release frequency.
Tier 2, Avoidance of Risk-Significant Plant Configurations, considered potential risk-significant plant operating configurations. Tier 3, Risk-Informed Plant Configuration Control and Management, considered risk evaluations of configurations when entered. The licensee states that the Tier 3 requirement is addressed at STP by the CRMP, which was incorporated previously into the TS by the license Amendments 85 and 72 for Units 1 and 2, respectively, on October 31, 1996. These amendments extended the AOT for the standby diesel generators (DG) to 14 days and the AOT for the essential cooling water and essential chilled water systems to 7 days. The NRC SER for the WCAP-14333-P concluded that the risk analysis in WCAP-14333-P supported the proposed TS changes and was acceptable subject to the following conditions which must be addressed in each plant-specific license amendment request referencing the WCAP-14333-P:
- 1. Confirm the applicability of the WCAP-14333-P analyses for the plant.
In its submittal the licensee states that it used the important parameters and assumptions of the WCAP to evaluate safety systems parameters including RTS and ESFAS signals and determined that the WCAPs generic analyses were applicable to the AOT and BTT extensions at STP. Three RTS and ESFAS plant-specific functions were not included in the generic evaluations for justifications supporting WCAP-10271 and WCAP-14333: (1) reactor coolant pump breaker position (single loop and two loop), (2) automatic switchover of safety injection suction to containment sump on low-low refueling water storage tank level, and (3) loss of power. The STP design does not include the first function and no changes are being proposed for the second function (Functional Unit 7 of Table 3.3-2). For the third function, the licensee evaluated the impact of relaxing the AOT and BTT. The standby DG start signals on low bus voltage are based on 2-out-of-4 logic. Bypassing a single instrument loop reduces this logic to 2-out-of-3. The licensee evaluation determined that with no operator action, the proposed change could increase the likelihood of DG failure to approximately 8.6E-06. This is insignificant compared to the probability of DG unavailability due to all causes, which is on the order of 8E-02. The small change in signal unavailability does not affect the automatic start capability of the standby DG on loss of power to its associated bus.
- 2. Address the Tier 2 and Tier 3 analyses, including the CRMP insights, by confirming that these insights are incorporated into the referenced licensees decisionmaking process before taking equipment out of service.
In its submittal the licensee states that the STP currently has a risk-informed on-line maintenance tracking and control process in place. The CRMP was incorporated into the STP TS in October 1996 by license amendments. The NRC staff in its SE for these amendments concluded that the STP had provided the necessary assurances that appropriate assessments of the overall impacts on safety functions would be performed prior to any maintenance or other operational activities, including removal of equipment from service. This risk-informed online maintenance tracking and control process is implemented and governed by a plant procedure. The licensee will add unavailability of the SSPS train and of the ESFAS train to the CRMP in implementing the proposed changes. The licensee has completed an analysis of the effects of having one
and two analog channels in bypass at all times for reactor trip and safeguards actuation signals. The change in CDF is insignificant even with no operator action credited to initiate the actuation signals. According to the licensees evaluation, for a single analog channel to be in bypass for an indefinite period has no direct effect on safety except to degrade the actuation logic a little. The resulting change in CDF is insignificant. There is no benefit to tracking analog channel bypass times. Therefore, the licensee concludes that the effects of placing instrument channels in bypass are not required to be included in the CRMP.
During plant operation in accordance with the current TS requirements, the analog channel operational tests (ACOTs) are periodically performed for each complete SSPS channel.
ACOTS verify that the trip setpoints are within the required range and accuracy. However, when the proposed changes are implemented, ACOTs will be performed in a bypassed condition. Since cycling of the complete channel with associated SSPS input relays could result in a partial trip, the associated SSPS input relays cannot be tested during normal plant operation. Therefore, for ACOTs during plant operation, the SSPS input relays will be excluded. These relays will be tested only at refueling outages (at an interval of 18 months),
when the entire SSPS channel including its associated input relay is being tested. Notes 19 and 7, as described in 3.2 above, are being added to indicate that surveillance tests for SSPS input relays are to be performed at refueling outages (once every 18 months). In its submittal the licensee states that the similar change regarding testing of the input relays on refueling outage periodicity rather than as a part of the ACOT during plant operation was previously approved by the NRC staff on September 30, 1993, in Vogtle Electric Generating Plant License (Amendments 67 for Unit 1 and 46 for Unit 2).
In its submittal the licensee states that, with the implementation of testing in bypass, the spurious reactor trip or safeguards actuation will be avoided since the partial trip conditions that would have been present will be eliminated. Although the trip logic configuration of 2-out-of-4 will be reduced to 2-out-of-3, the logic requiring signals from two additional channels to actuate the protective function will be maintained. Placing a channel in bypass for additional time reduces the availability of signals to initiate component actuation for event mitigation, but as shown in WCAP-14333, the impact on safety is insignificant because of other signals and/or operator actions are available to trip the reactor or actuate a component. The proposed AOT and BTT relaxations were approved by the NRC staff in the SER for WCAP-14333-P-A, Revision 1, and the proposed changes involve no additional modifications to trip setpoints, surveillance requirements, or channel responses that would affect the safety analyses. The licensee adds that implementing the proposed changes will reduce spurious actuations, challenges to the plant safety systems, and thus will increase plant availability. Administrative controls will be in place to prevent the simultaneous bypassing of more than one redundant protection set at any one time and to restore the system to normal operation, and the status of the bypassed channel will be indicated both in the control room and locally. The proposed changes to hardware design to support testing in bypass has considered equipment qualification, reliability, fault conditions, and all credible failures. The proposed hardware modifications meet all the conditions specified by the NRC staff SER for WCAP-10271 and its supplements. The hardware modifications are designed so that credible failures will not automatically place a function in a bypassed condition.
The proposed changes to the AOTs and BTTs have an insignificant impact on plant safety as determined by the calculated CDF. The proposed changes do not result in RTS and ESFAS setpoint changes. The NRC staff agrees with the licensee that the proposed amendments will not increase the probability of or consequences of an accident previously evaluated or create the possibility of a new or different kind of accident from any accident previously evaluated. Placing a channel in a bypass for additional time increases the time a channel is unavailable, but the impact on safety, in accordance to WCAP-14333 is insignificant.
In addition, the potential for an inadvertent reactor trip and inadvertent actuation of safety systems due to human error or a spurious actuation is greatly reduced. The proposed administrative, editorial, and format changes do not affect plant safety, and the licensees responses to the conditions included in the NRC staffs safety evaluation report for the WCAP-14333-P are acceptable. Therefore, the NRC staff finds the proposed amendments acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Texas State official was notified of the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change 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. The NRC staff has determined that the amendments involve 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 amendments involve no significant hazards consideration, and there has been no public comment on such finding (66 FR 44177 dated August 22, 2001). Accordingly, the amendments meet 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 amendments.
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 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.
Principal Contributor: S. Athavale Date: March 19, 2002