ML20065Q403
| ML20065Q403 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 12/14/1990 |
| From: | Hairston W ALABAMA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-070, REF-GTECI-094, REF-GTECI-NI, TASK-070, TASK-094, TASK-70, TASK-94, TASK-OR GL-90-06, GL-90-6, NUDOCS 9012170182 | |
| Download: ML20065Q403 (4) | |
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e Alit *ma Power Company,
C 40 inverness Center Parkway Post Ofice Dox 1295
- Darmingham. Alabama ?5201 Telephone 205 068 5581 W. G. Hairston, ill Senior Vice President Nuclear Operations Alabama Power.
December 14,.1990~
the soahem electre system 10CFR50.54(f)
Docket Nos. 50-348 50-364 U. S. Nuclear Regulatory Commission
- ATTN. Document Control Desk' Vashington, D. C. 20555 Gentlemen:
Joseph H. Farley Nuclear Plant Units 1 an'd 2 Response to Generic Letter (G.L.).90-06:
Resolution of-Generic Issue 70,'"Pover-Operated: Relief Valve and' Block Valve Reliability," and Generic Issue 94,." Additional Low-Temperature Overpressure Protection for Light-Vater Reactors" On--June 25,.1990 the NRC issued Generic Letter (G.L.) 90-061-Resolution of Generic' Issue 70, " Power-0perated Relief Valve and Block Valve Reliability,"
-and Generic Issue 94, " Additional Low-Temperature Overpressure Protection for Light-Vater Reactors." In G.L. 90-06;the NRC delineated specific recommendations which address the concerns of Generic Issues 70 and 94.
The NRC requested utilities pursuant to 10CFR50.54(f)-to commit'to:
- 1) take additional measures to increase the-reliability of power-operated relief valves (PORV's) and~PORV block valves,
- 2) modify;the' technical specification associated with the reactor coolant system (RCS) relief valves'to ensure that safety-related functions performed by the'PORV's are maintained, and 3).
modify-the RCS lov temperature overpressure protection (LTOP) system technical specification to account.for the increased: likelihood of an overpressure event during operating Modes 5 and 6:when the RCS.is water-solfd.
At Farley Nuclear Plant, the PORV's function is to automatically relieve RCS pressure below the pressurizer safety valve setpoint and.to reduce RCS pressure upon demand by the operator.1 Automatic actuation'of the PORV's is.
not assumed to mitigate the consequences of a design basis accident as-described in Chapter.15 of the FSAR. The safety ~ functions performed.by the PORV's are:
- 1) inactive valves which form part offthe RCS boundary, and 2) manual operation astrequired by emergency operating procedures.~ The PORV's are= utilized'to depressurize the RCS in1the event of a steam generator tube rupture and during natural circulation;-however, automatic actuation ~is not-relied upon by the emergency _ operating procedures'. The PORV's are.not utilized for-low temperature overpressure protection; instead, the' residual heat removal suction relief valves perform this_ function.
l Section 2 of the Enclosure B to G.L. 90-06 states that additional
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restrictions regarding the restart of inactive reactor coolant pumps.and the operability of high pressure safety injection-pumps?should be added to the technical' specification in order to reduce the risk of a lov temperature overpressure event.
Farley Nuclear-Plant-already has'such technical specification requirements.
9012170182 901214 PDR ADOCK 05000348 Anf C P
PDR y V/ 7 1700 5
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- - -.1 U. S. Nuclear Regulatory Commission 10CFR50.54(f)
Page 2-Alabama Power Company has reviewed the recommendations of G.L. 90-06 and i
provides as Enclosure 1 a description of the maintenance and procurement practices for PORV's and block valves at Farley Nuclear Plant.
The current inservice Inspection and testing practices-are in agreement with the recommendations for improved reliability as outlined in Section.3 of~
Enclosure A to G.L. 90-06 vith one exception.
Alabama' Power Company commits to add:the valves in the backup nitrogen supply system needed for.PORV operation to the Inservice Testing. Program.
Alabama Power Company is currently evaluating the suggested modified technical specifications. The proposed allowed outage times for an inoperable PORV for reasons other than excessive seat leakage, an inoperable PORV block valve, and an inoperable LTOP channel during Modes 5 and 6 would create a serious restriction on plant operation.
Therefore,' Alabama Power Company is evaluating means to justify modifying or lengthening the allowed outage times.
In addition, Alabama Power Company may wish to clarify PORV operability with a block valve closed for reasons such as periodic testing or excessive packing leakage which would not render the block valve inoperable.
Alabama Power Company vill submit a proposed change to the LTOP technical s
specification or a justification for not changing the current technical specification by the end of-the Unit I tenth refueling outage vhich is presently scheduled to begin in Harch of 1991. A change to the PORV:
technical specification or a justification for not changingLthe current technical specification vill be submitted by October of 1991'.
Additional time is needed to develop. plant-specific probabilistic risk analysis (PRA) models with one and two PORV's inoperable. The Farley Nuclear Plant PRA model is currently being developed in accordance with-the requirements of G.L. 88-20, " Individual Plant Examination (IPE)-for Severe Accident Vulnerabilities." Alabama Power Company believes that performing these two similar tasks in concert v111'best utilize-the.available resources.
Moreover, utilizing a plant-specific PRA model rather than a generic model vill add greater validity to the conclusions drawn from them.
If thare are any questions, please advise.
Respectfully submitted, ALABAMA POVER COMPANY t),
h V. G. Hairston-, III VGil,III/BHV:mgd 25.16 Enclosure SVORN TO AND SUBSCRIBED BEFORE HE cc Mr. S. D. Ebneter
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Hr. S. T. Iloffman THIS /
DAY OF h for 1990 M/y % 4L M : eff NoJr.r9 Public riy Commission Expires:_/
/7 M
l ENCLOSURE 1 Response to the Section 3 of Enclosure A to G.L. 90-06 NRC Recommendation Include PORV's and block valves within the scope of.an operational quality assurance program that is in-compliance with 10CFR Part 50, Appendix B.
This program should include the following elements:
a..The addition of PORV's_and block valves to-the l ant l
operational Quality Assurance List.
- b. Implementation of a maintenance / refurbishment 3rogram for PORV's and block valves-that is. based on'the manufacturer's recommendations or guidance and is implemented by trained plant maintenance personnel,
- c. When replacement parts ~and spares, as.vell as complete components, are required for existing non-safety-grade PORV's and block valves-(and associated-control systems), it is the intent of this generic. letter that these items may be procured in accordance vith the original construction-codes and standards.
APCo Response The PORV's and PORV block valves are included within.the scope of the Farley Nuclear Plant Quality Assurance (0A) Program-(which conforms to the requirements of 10CFR Part 50,. Appendix B).
The valves are presently incorporated in the.FSAR "0-List". _ Maintenance on these valves is_ performed in accordance with the OA Program by l
trained personnel.
Alabama Power Company has developed a preventive l
maintenance program for the PORV's and the block' valves which l
l ensures a continuous high degree of reliability..This program takes into consideration = guidance provided by the PORV and PORV block valve manufacturer. All replacement or spare parts for the PORV's and the block-valves are procured with'the quality assurance requirements of 10CFR Part 50, Appendix B imposed ift
- 1) the part is required for the PORV or block valve to perform its safety function, or 2) the> failure of_the'part would result in the PORV or block valve not being able to, perform its safety function.
NRC Recommendation Include PORV's,_ valves in-PORV control air. systems, and block. valves within the scope offa program covered-by Subsection IVV, " Inservice Testing of Valves in' Nuclear Power Plants," of Section XI of the ASME BoilerLand Pressure Vessel Code.
Struke. testing of PORV's 1should only be performed during Mode 3 (Hot Standby) or Mode 4' (flot Shutdown) and in all cases prior.to establishing conditions where the PORV's are used forLlow-temperature overpressure protection.-
Stroke testing of the PORV's should not'be performed during power operation.
Additionally,'the,PORV block valves should be included in the expanded MOV test program discussed in NRC G.L. 89-10,
" Safety-Related Motor Operated Valve Testing and Surveillance,"-
dated June 28, 1989.
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ENCLOSURg 1 i
Page 2l-APCo Response Both the pressurizer PORV's and PORV' block valves are included'in-the Parley. Nuclear Plant Inservice Testing-Progtam which compliest with-the requirements of ASME Section XI. -The instrumen. 41r system is not safety-related and -is not assumed to be-availaV.-.o-open-the PORV's-during a design basis. accident.- Instead, a seismically.
i qualified. backup nitrogen supply.is installed-to perform _th s function.- The valves'in the backup nitrogen' supply piping that are required for_PORV operation vill _befadded to the Inservice Testing; Programe The. requirement to strake~ test.the PORV's prior _.to_the-2 time-when they provide lov-temperature overpressure protection is not applicable'to'Farley-Nualear Plant since they are not used-for this function.< - In accordance with the Inservice Testing Program the PORV's are stroke' tester', during c Mode 5.
The-PORV's installed at-Farley Nuclear Plant.are nat air pilot-actuated valves, but instead,
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are air-operated-valves thereforei RCS~ pressure does'not provide i
the' opening iorce to manipulate the valve. - The air supply.to-the-valve provides'the necessery force to open the PORV's during operating conditions.- The6efore, performance of stroke. testing at actual' operating conditions:is not_ required to-demonstrate-the valve's ability to open.
PORV-block valves are presently included-in the expanded MOV test program as described in our r.esponse.to NRC G. L. 89-10.
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