ML20236M966

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Discusses from Southern Nuclear Operating Co Requesting NRC Review Interpretation of Application of TS 3/4.9.13 at Farley Nuclear Plant,Units 1 & 2 During Modes 5 or 6,or When Defueled
ML20236M966
Person / Time
Site: Farley  Southern Nuclear icon.png
Issue date: 02/12/1997
From: Charemagne Grimes
NRC (Affiliation Not Assigned)
To: Jacob Zimmerman
NRC (Affiliation Not Assigned)
Shared Package
ML20236J990 List: ... further results
References
FOIA-98-155 50-364-96-13, NUDOCS 9807140344
Download: ML20236M966 (3)
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  • ( February ~ 12, 1997 MEMORANDUM TO: Jacob 1. Zimmerman, Project Manager Project Directorate 1-2 1 FROM: Christopher 1. Grimes, Chief

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SUBJECT:

REQUEST FOR WRITTEN INTERPRETATION OF TECHNICAL SPECIFICATIONS By letter dated November 27,1996, Southern Nuclear Operating Company (SNC) requested NRC review of its interpretation of the application of Technical Specification (TS) 3/4.9.13,

" Storage Pool Ventilation (Fuel Movement)," at Farley Nuclear Plant (Farley) Units 1 and 2 during modes 5 or 6, or when defueled. SNC had prepared the interpretation to address a concern stemming from an observation made by the NRC resident inspectors during the Farley Unit 2 fall 1996 refueling outage. This concern was documented as Unresolved item 50-364/96-13-01, " Penetration Room Filtration Operability Requirements for Spent Fuel Pool," in NRC inspection Report 50-364/96-13, dated December 23,1996. Specifically, on ,

October 30,1996, while fuel movement within the spent fuel pool was in progress, the I inspectors observed Farley performing surveillance testing on Train B of the penetration l room filtration (PRF) system, making the system inoperable with respect to the spent-fuel-  !

room-filtration function. The inspectors' concern was that, during the test, PRF Train A appeared to be inoperable also. This concern was based upon a literal reading of TS 3.9.13, which requires two ladaaaadant PRF systems to be operable during fuel movement, and the TS definition of operability, which requires both a normal and an emergency ac electrical l power source. During the testing, the Train A PRF system was supported by the Train B ,

offsite and onsite emergency ac power sources, because the Train A ac sources were I inoperable.

l In its written interpretation for applying TS 3/4.9.13 during modes 5 and 6 and when defueled, SNC concluded that a single offsite ac source and a single onsite emergency ac source are sufficient to satisfy the ac electrical power requirements to support the l operability of the two required independent PRF systems. This conclusion is based on i

consistency with (a) TS 3/4.8.1.2, "A.C. Sources Shutdown," which only requires a single l offsite ac source and a single onsite emergency ac source to be operable, and (b) the degree of mechanical and electrical indeperidence necessary to satisfy the licensing basis during i modes 5 and 6 and when defueled. That is, the assumption of a single failure and concurrent loss of all offsite or onsite power is not required.

i CONTACT: Craig Harbuck, TSB/NRR 415-3140 9007140344 980624 PDR FOIA PDR L d

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Jacob 1. Zimmerman February 12, 1997 Although TS 3.8.1.2 only requires a single operable offsite ac source and a single operable onsite emergency ac source, satisfying these requirements is insufficient to meet TS 3.9.13, which requires two operable PRF systems. Each PRF system must be able to start automatically to satisfy the assumptions for the PRF apont fuel room-filtration function as described in FSAR Section 15.4.5 for the design basis fuel handling accident. The analysis or any design basis accident during shutdown conditions, including the analysis of the design basis fuel handling accident, assumes a loss of the offaite ac source (but not a concurrent single failure). In the Farley design, with both trains of the onsite ac electrical power distribution system cross connected and supported by a single onsite emergency sc source, a loss of the offsite ac source will result in load shedding of the opposite train loans I which defeats the automatic actuation capability of the opposite train PRF system.

Therefore, each PRF system must have its own operable onsite emergency ac source to maintain its automatic actuation capability and be considered operable in accordance with TS 3.9.13. Consequently, the NRC staff does not agree with SNC's interpretation of the application of TS 3/4.9.13 during modes 5 and 6 and when defueled. The Electrical Engineering Branch believes this issue may have ger;eric implications and is accordingly _-

referring it separately to the Events Assessment and Generic Communications Branch.

With respect to the situation observed by the resident inspectors, the staff concludes that the Train A PRF system became inoperable when the Train A onsite emergency ac source was made inoperable for maintenance. Within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> of Train A becoming inoperable, fuel movement within the spent fuel pool should have ceased in accordance with Action a of TS 3/4.g.13. By concurrently making the Train B PRF system inoperable for surveillance testing, Farley created a loss of function condition because the Farley PRF system, as designed, would not have been capable of automatically mitigating the consequences of the Farley design basis fuel handling accident. In this situation, fuel movement within the spent fuel pool should have ceased immediately.

It is recognized that the assumptions of the fuel handling accident as described in FSAR Section 15.4.5 may be overly conservative. Nevertheless, TS must ensure that the 1 assumptions of the FSAR accident analysis remain valid. TS 3.9.13 and the Farley TS  !

definition of operability do this. If SNC desires a less restrictive licensing basis relative to  !

the fuel handling accident, it should consider revising its licensing basis analysis and TS )

3/4.9.13 be seeking a license amendment in accordance with 10 CFR 50.90. Until such a '

change in the operating license is granted by the Commission, Farley Units 1 and 2 must be operated in compliance with the current TS requirements, cc: RZimmerman SVarga JZwoiinski AChaffee 1

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Jacob 1. Zimmerman February 12, 1997 Although TS 3.8.1.2 only requires a single operable offsite ac source and a single operable onsite emergency ac source, satisfying these requirements is insufficient to meet TS 3.9.13, which requires two operable PRF systems. Each PRF system must be able to start l

automatically to satisfy the assumptions for the PRF apont-fuel-room-filtration function as l described in FSAR Section 15.4.5 for the design basis fuel handling accident. The analysis or any design basis accident during shutdown conditions, including the analysis of the design basis fuel handling accident, assumes a loss of the offsite ac source (but not a '

concurrent single failure), in the Farley design, with both trains of the onsite ac electrical power distribution system cross connected and supported by a single onsite emergency ac .

source, a loss of the offsite ac source will result in load shedding of the opposite train loads which defeats the automatic actuation capability of the opposite train PRF aystem.

Therefore, each PRF system must have its own operable onsite emergency ac source to maintain its automatic actuation capatiility and be considered operable in accordance with l

TS 3.9.13. Consequently, the NRC staff does not agree with SNC's interpretation of the l application of TS 3/4.9.13 during modes 5 and 6 and when defueled. The Electrical Engineering Branch believes this issue may have generic implications and is accordingly referring it separately to the Events Assessment and Generic Communications Branch.

With respect to the situation observed by the resident inspectors, the staff concludes that the Train A PRF system became inoperable when the Train A onsite emergency ac source

! was made inoperable for maintenance. Within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> of Train A becoming inoperable, l fuel movement within the spent fuel pool should have ceased in accordance with Action a l of TS 3/4.9.13. By concurrently making the Train 8 PRF system inoperable for surveillance testing, Farley created a loss of function condition because the Farley PRF system, as ,

designed, would not have been capable of automatically mitigating the consequences of the l Farley design basis fuel handling accident. In this situations, fuel movement within the spent i fuel pool should have ceased immediately.

It is recognized that the assumptions of the fuel handling accident as described in FSAR l

Section 15.4.5 may be overly conservative. Nevertheless, TS must ensure that the assumptions of the FSAR accident analysis remain valid. TS 3.9.13 and the Farley TS definition of operability do this. If SNC desires a less restrictive licensing baals relative to the fuel handling accident, it should consider revising its licensing basis analysis and TS 3/4.9.13 be seeking a license amendment in accordance with 10 CFR 50.90. Until such a change in the operating iicense is granted by the Commission, Farley Units 1 and 2 must be operated in compliance with the current TS requirements.

cc: RZimmerman JZwolinski SVerga AChaffee DISTRlRijTION:

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