ML20149J811
| ML20149J811 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 02/12/1988 |
| From: | NRC OFFICE OF SPECIAL PROJECTS |
| To: | |
| Shared Package | |
| ML20149J770 | List: |
| References | |
| NUDOCS 8802230225 | |
| Download: ML20149J811 (3) | |
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' UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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.tAFETY EVALUATION BY THE OFFICE OF SPECIAL PROJECTS SUPPORTING AMENDMENT NO. 144 TO FACILITY OPERATING LICE 1SE NO. DPR-33 APENDMENT NO.140 TO FACILITY OPERATING LICENSE NO. DPR-52 AMENDMENT NO. 115 TO FACILITY OPERATING LICENSE NCr. DPR-68 TENNESSEE VALLEY AUTHORITY BROWNS FERRY. NUCLEAR PLANT, UNITS 1, 2 AND 3 DOCKETS NOS. 50-259, 50-260 AND 50-296 1.0, INTRODUCTION By letters dated August 28, 1985 and April 7, 1986, Tennes;ee Valley Authority (the licensae) requested a chanca to the Browns Ferry Nuclear Plant, Units 1, 2, and 3 Technical Specifications (TS) to revise functional test frequencies listed in Table 4.2.B.
The change replaces functional test frequencies for Core Spray logic, Reactor Core Isolation Cooling (RCIC) Initiating and Isolating logic, High Pressure Coolant Injection (HPCI) Initiating and Isolation logic, Automatic Depressurization System (ADS) logic, Low Pressure Coolant Injection (LPCI)
Ir,itiating and Containrent Spray logic, Core Spaay Auto Initiation Inhibit, and PPCI Auto Initiation Inhibit from once per 6 months to once per 18 months.
2.0 EVALUATION Subsequent to the Salem Anticipated Transient Without Scram (ATWS) events of i
February 22 and 25,1983, the NRC issued Generic Letter 83-28 reouesting that i
all licensees of operating reactors, applicarts for operating licenses, and holders of construction pemits respond to generic issues raised by the analyses of these two A7WS events.
Item 4.5.3 of this generic letter requested that licensees and applicants review the existing Peactor Protection Systen (RPS) on-line functional test :. tervals required by their plant TS. The licersees/
applicants were to ensure that current and prepnsed intervals for such testing are consistent with a goal of achieving high RPS availability considering uncertainties in corponent failure rates, uncertainties in connon mode failure l
rates, reduced redundancy during testing, operator errors during testing, and compenent wear caused by the testing.
I The NRC determined that the existing surveillance intervals for channel functional tests, channel calculations and logic system functional tests as defined in NUREG-0123, Revision 3, Boiling Water Reactnr Standard Technical Specifications (BWRSTS), provided reasonable assurance of compliance and consistency with the above statec goals and objectives for RPS testing.
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The Boiling Water Reactor Owners' Group (BW OG) decided to attempt to resolve these issues generically, it comissioned G:ineral Electric (GE) to perform generic analyses and apply the generic results to the individual BWP plants.
The generic analyses are applicable to a vast nMerity of plants that have a relay RPS, as well as to tbc rest of the plants ' hat have solid-state RPS.
Two GE topical' reports were issued:
(1) NEDC-30844, in which a represertative BWR plant is er.alyzed and a technical basis is proviled for ensuring that the current RPS surveillarce test intervals meet the recunmerdations of Generic Letter 83-28, item 4.5.2, and (2) FFDC-30851P, ir which the base case results from NEDC-30844 are used to establ Wh a basis for e> tending the current RPS surveillance test intervals ard allowable outage tires.
In these reports, relie.oility analyses with fault tree modelling were used to estimate RPS failure frequency. The acceptance guidelines used by GE fec the TS changes is based en r.et increase in risk.
This is the difference betwe3n the increase in risk that would result from the TS changes and the decrN!e in risk that would result from the reduced likelihood of 11 advertent ~cr.ims or exceeding the Limiting Cenditions of Operatiers.
If the net change in risk is determined to be insignificant, the TS changes are considered acceptable.
On the besis of the review of the topical and the LRC contractors' Technical Evaluation Repert (TER), the NRC issued Safety Evaluations (SE) on July 15, 1987 for relay RPS and on January 24, 1988 for solid-state RPS.
In both SEs, the NRC staff found the analyses presented acceptable fer supporting a determination that the BWRSTS PPS test intervals are censistent with the high PPS availability requested by Generic Letter C3-28. Iten 4.5.3.
The TS for Browns Ferry Nuclear Plant, Units 1, 2 and 3, currently require functional testing once per 6 months. The licensees' request to extend the r
functional testing to once per 18 months will allow performance of complex logic surveillance testing at a time when the urit is shut down. These cceplex surveillance tests require nutrerous temporary alterations and/or administrative controla and are inherently prone to undesired actuations and potential for cperator errer while also reducing redundancy of protectier during the testing.
Testing the RPS system at 18 month intervals is consistent with the interval that the NRC has determined to be adequate to achieve the goal of high RPS availability considering urcertainties in component failure rates, uncertainties in comon mode failure rates, reduced redurdancy during testing, and component weer caused by the testing. The staff, therefore, finds this change acceptable.
3.0 ENVI,RONMENTAL CONSICERATION These arendments involve a change to a requirerent with respect to installatien or use of a facility component located rithin the restricted area as defineo in 10 CFR Fart 20 and changes to the surveillance requirerents. The staff has deternined that the amendrents involve no significent 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 er cumulative occupational radiation exposure.
The Comission has previously issued a proposed i
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' finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 C'il 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
The staff 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 ir the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendments will not be ininical to the common defense and security nor to the health and safety of the public.
Principal Contributor: John Stang Dated: February 12, 1988 l
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