ML20206R647

Board Notification 86-019:forwards SER Re Reanalysis of Thermal Response of Asco Solenoid Valves Used at Facility. Use of Valves Acceptable

ML20206R647
Person / Time
Site:	Vogtle
Issue date:	09/15/1986
From:	Jacqueline Thompson Office of Nuclear Reactor Regulation
To:	Linenberger G, Margulies M, Paris O Atomic Safety and Licensing Board Panel
Shared Package
ML20206R654	List: ML20206R647 ML20214P397
References
TASK-AS, TASK-BN86-019, TASK-BN86-19 BN-86-019, BN-86-19, NUDOCS 8609160060
Download: ML20206R647 (3)

Text

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0,, UNITED STATES i 78 o NUCLEAR REGULATORY COMMISSION

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% , , , , ,+* SEP 15 Egb Docket Nos.: 50-424 and 50-425 MEMORANDUM FOR: The Atomic Safety and Licensing Board Panel for Vogtle (M. Margulies, O. Paris, G. Linenberger)

'FROM: John W. Thompson, Project Manager PWR Project Directorate #4 Division of PWR Licensing-A

SUBJECT:

BOARD NOTIFICATION REGARDING ENVIRONMENTAL QUALIFICATION OF ASCO SOLEN 0ID VALVES FOR V0GTLE UNITS 1 AND 2 (B0ARD NOTIFICATION NO. 86-19)

Enclosed is a safety evaluation prepared by the staff that addresses the environmental qualification of the ASCO solenoid valves used in Vogtle Units 1 and 2. The evaluation resolves the concern raised in a previous Board Notification (BN), No. 86-18, dated August 25, 1986. In the pre-vlous BN, the staff informed the Board that the acceptability of the methodology used in justifying the qualification of the ASCO valves when exposed to superheated steam conditions following a MSLB outside contain-ment was in question. In a subsequent meeting on August 27-28, 1986 and in follow-up infonnation submitted on September 2,1986, the applicant presented their case for finding the ASCO valves appropriately qualified.

In the enclosed evaluation the staff finds the applicant's re-analysis of the thermal response of the ASCO solenoid valves to be acceptable, and, therefore, qualified.

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l Jo n W. Thompson, Project Manager R Project Directorate #4 Division of PWR Licensing-A

Enclosures:

As stated cc: ACRS(10)

EDO Parties to the Proceeding (Seenextpage)-

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3 ENCLOSURE 1 Suunnary of NRC Staff Evaluation Regarding Qualification of ASCO Solenoid Valves For Vogtle Units 1 and 2 By an NRC staff memorandum dated August 25, 1986 (Board Notification No.

86-18), the Atomic Safety and Licensing Board Panel for Vogtle was notified of a staff request for additional information from the applicants on the Vogtle main steamline break (MSLB) analysis. The staff's request questioned, in part, the applicability of the themal lag methodology used to establis,h the qualification of ASCO valves exposed to superheat conditions following a main steamline break outside containment.

Of the four ASCO valve models used in safety-related applications at the Vogtle plant, the only one to which these concerns applied is ASCO valve model NP8321 located in the Main Steam Isolation Valve (MSIV) area. The staff's request for infonnation did not, in any manner, question the environmental qualification of the other three ASCO valve models:

Model NP8320 valves are fully qualified by test to 420*F. This I

qualification level exceeds the expected conditions in the MSIV area.

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Model NP8316 is not required to perfonn any function to mitigate a MSLB in the MSIV area.

Model 206-381 solenoids 'are not located in the MSIV area and perform no essential function for, a MSL.B in the MSIV area.

Applicants met with the sta'ff on August 27 and 28,1986, and provided information to address the staff's concerns. Additional supporting information was provided by letters from applicants dated August 21, 1986 and September 2,1986 to specifically address the environmental qualification of ASCO valve model NP8321 located in the MSIV area. Applicants provided the Vogtle-specific MSLB temperature profiles calculated for the locations in

7-t the MSIV area and performed a thermal lag analysis to demonstrate that the surface temperature of ASCO valve model. NP8321 exposed to the calculated conditions, would reach a maximum of 326*F. The surface temperature is enveloped by the staff accepted qualification temperature of 346*F for this valve.

The staff has reviewed the information submitted by applicants to support the above statements and has concluded that applicants have provided an acceptable response to the concerns raised in the August 12 request for information as it applies to ASCO valves. The staff has also reviewed the methodology used in calculating the Vogtle specific environmental conditions resulting from a MSLB in the MSIV area and found it to be acceptable. The~

staff's detailed technical evaluation which forms the basis for these conclusions is attached.

Based on the staf f's review, the staff finds that the concerns raised regarding the qualification of ASCO valves in Board Notification 86-18 have been adequately and fully resolved. The responses to the information requested in the August 12, 1986 letter do not impact or alter any previous conclusions or staff testimony on Contention 10.5 regarding the qualification of ASCO valves used in the Vogtle plant.

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[y; G ' SAFETY EVALUATION REPORT l .: .x.C.' - '

'! ENVIRONMENTAL-QUALIFICATION OF

' ASCO SOLEN 0ID VALVES V0GTLE ELECTRIC GENERATING PLANT, UNITS 1 & 2

,- . Docket Nos. 50-424/425

• I. Introduction -

By' memorandum dated August 25,1986 (Reference 1), the staff notified the Vogtle Atomic Safety and Licensing Board that the methodology used for the qualification of ASCO valves exposed to superheated steam conditions following a main steam line break (MSLB) outside containment was in question. The staff's request for additional infonnation, dated August 12,1986 (Reference 2), was attached to

' Board Notification 86-18. The Applicant informed the staff by letter dated August 21, 1986 (Reference 3) that the staff's concern is confined to the four, NP 8321 ASCO solenoid valves in the control building. The other ASCO i valves would either not be subject to environmental conditions that exceed their qualification temperatures or are not required to function in the event of a MSLB.

In a subsequent meeting held on August 27-28, 1986 and by letter dated September 2,1986 (Reference 4), the applicant presented a re-analysis of the environmental qualification of the NP 8321 solenoid valves, using a methodology more conservative than that previo~usly used.'

] II. Evaluation The applicant's more recent analysis used Vogtle plant-specific mass and energy release data as input to Bechtel FLUD code to calculate the temperature profiles in the control building for a spectrum of MSLBs. A thermal lag analysis based on a more conservative methodology was then performed.

- The previou's into three thermal analysis divided the temperature response of a component phases:

(1) the component temperature rise from ambient to the saturation temperature corresponding to the environment pressure; (2) the component remaining at saturation until the condensate is completely vaporized; (3) the component temperature rise based on forced convection heat transfer. -

The staff's request for additional information (Reference 2) was primarily directed at the methodology for calculating the duration of the second phase. In the revised analysis, the first two phases were assumed to occur instantaneously,

i.e., the initial component temperature was assumed to be the saturation temperature.

The staff finds this assumption acceptable since the approach is more conservative i

than that prescribed in NUREG-0588, " Interim Staff Position on Environmental Qualification of Safety-Related Electrical Equipment". .-

The applicant used the calculated component interior temperature, instead of the surfact temperature, as prescribed in NUREG-0588, to assess equipment qualifi-cation. However, the applicant demonstrated in attachment 3 of Reference 4 that the temperature difference across the valve body for the ASCO NP 8321 solenoid valves would be less than 0.8'F. Therefore, the applicant added l'F to the cal-l p culated NP 8321 valve body temperature to obtain a surface temperature of 326*F.

The qualification temperature of the NP 8321 valves based on test data is 346'F.

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With a 20*F margin, the staff concludes that the ASCO NP 8321 solenoid valves

,73 are qualified for the worst case. environmental conditions following a MSLB v outside containment. '

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In response to a staff concern over the acceptability of the FLUD code, the

' applicant discussed at length, in the meeting on August 27-28, 1986, the results of a code verification analysis that was performed. The infortnation for four pertinent cases was included in Attachment 1 to Reference 4. In all~ cases, the i results calculated by the FLUD code compared favorably with the Bechtel COPDA and COPATTA codes, Battelle Frankfurt test data, and state point hand calculations.

Based on the FLUD code verification results. There is reasonable assurance that the Vogtle environmental temperature profiles are acceptable.-

III. Conclusion Based on the above evaluation, the staff concludes that the ASCO UP 8321 solenoid valves used at Vogtle, Units 1 and 2 are qualified to withstand superheated steam conditions that may occur following a MSLB outside containment.

IV. References

1. Memorandum from M. Miller to the Atomic Safety and Licensing Board Panel for Vogtle, dated August 25, 1986, subject: Board Notification' No. 86-18 Regarding ASCO Solenoid Valves for Vogtle Units 1 and 2.

2. Letter from M. Miller (NRC) to R. Conway'(Georgia Power Company)', dated August 12, 1986, subject: Request for Additional Infonnation on Confirmatory

) Item 9 - Steamline Break Analysis Outside Containment.

3.

Letter from J. A. Bailey (Georgia Power Company) to H. Denton (NRC),

dated August 21, 1986, subject: SER Confirmatory Item 9 - Steamline Break Outside Containment.

4.

Letter from J. A. Bailey (GPC) to H. Denton (NRC), dated September 2,1986, SER Confinnatory Item 9 - Steam Line Break Outside Containment.

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