ML19326E243
| ML19326E243 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/25/1980 |
| From: | Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Clark R, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 649, NUDOCS 8007280651 | |
| Download: ML19326E243 (3) | |
Text
---
W.%
Vruo1NIA Er.nc rurc Axn PowE n Coxi Axy RIcnnoxn,VIRGINI A 20061 July 25, 1980 Mr. Harold R. Denton, Director Serial No. 649 Office of Nuclear Reactor Regulation N0/RMB:smv Attention:
Mr. Robert A. Clark, Chief Docket Nos. 50-338 Operating Reactors Branch No. 3 50-339 U. S. Nuclear Regulatory Commission License Nos. NPF-4 Washington, D. C. 20555 NPF-7
Dear Mr. Denton:
MULTIPLE STRUCTURE ARS CONCERN NORTH ANNA UNIT NO. 1 This letter provides a summary of the results of Phase I of the Multiple Structure ARS Evaluation of North Anna Unit No.1 piping systems design.
The method of evaluation was as described in our letter Serial No. 510 dated June 6, 1980.
g The purpose of the Phase I evaluation was to determine which problems among the 68 requiring review are not substantially af fected by the consideration of l
Multiple Structure ARS and which problems will require a more detailed evalu-
)
ation before the full effects can be determined.
The Phase I engineering effort is now complete with all the 68 stress problems reviewed.
We have found that 36 of the computerized analysis problems are not substantially affected and will therefore require no further review.
These problems have been classified as " Category A" as defined in our letter Serial No. 510.
The remaining 32 stress problems have been classified as " Category B".
These remaining problems will receive further evaluation in Phase II of our effort.
The categorization of the initial 68 problems is listed is Attachment I to i
this letter.
Additionally, the review of the multiple structure ARS as l
applied to site analyzed small bore piping is completc., and it has been deter-I mined that there is no substantial effect.
l I
The Phase II ef fort, consisting of a calculational evaluction of the "Cate-gory B" stress problems, has begun on Unit 1.
As stated in our letter Serial l
No. 616 dated July 11, 1980 on North Anna Unit 2, we propose to conduct the Phase II effort for Units 1 and 2 in parallel, thus impacting our previous target date for completing Phase II on Unit 1 of September 15, 1980.
We Felieve that a minimum of four months will be required to complete Phase II f or both units af ter completion of Phase I on Unit 2.
Therefore, our target date for completing Phase II on _ Units 1 and 2 is now December 31, 1980.
As stated in our previous correspondence on this matter, if at any time during the detailed Phase II effort, results obtained clearly show that a design of a particular piping system or support cannot be justified against the concept of - multiple structure input, the system will be reviewed per Technical Speci-l fication requirements and appropriate action taken, i
80 07280651
)
- f l
+-v".
l l
vanuix A EttcThic Axu l'own:a Coxi'axv To Mr. Harold R. Denton, Director Please let us know if you have any question or comment on the above. We plan I
to submit a final detailed report upon completion of the Phase II effort but j
j would be available to discuss our progress on this matter with you at any time.
i Very truly yours, f*N B. R. Sylvia Manager - Nuclear Operations and Maintenance RMB/smv:SF2 cc:
Mr. B. J. Youngblood, Chief Licensing Branch No. 1 Division of Licensing Washington, D. C. 20555 Mr. S. A. Varg., Chief Operating Reactors Branch No. 1 Division of Licensing Washington D. C.
20555 i
Mr. James e. O'Reilly, Director Office of Inspection & Enforcement l
Region II Atlanta, Georgia 30303 i
i L
l
/
ATTACHMENT 1 MULTIPLE STRUCTLIRE ARS EVALUATION PHASE I Unit 1 Category A Categroy B MSK-101C MSK-101A MSK-101D MSK-101B MSK-102A MSK-102C MSK-102B MSK-102D MSK-103C MSK-103B MSK-103D MSK-103E MSK-103F MSK-103R MSK-103G MSK-103AC MSK-103J MSK-103AM MSK-103K MSK-104A MSK-103AE MSK-104D MSK-103AN MSK-107B MSK-103AP MSK-111B MSK-104F MSK-111C MSK-104G MSK-114E MSK-104H MSK-114F MSK-105F MSK-114K l
MSK-105G' MSK-114L M5i:-105H MSK-114M MSK-105J MSK-118B MSK-107C MSK-118C MSK-107D MSK-118D MSK-lllN MSK-118F MSK-111Q MSK-118K MSK-1115 MSK-118N MSK-114B MSK-121A MSK-114D MSK-121B MSK-114C SSR-7 (SA-7223)
MSK-118A SSR-7 (SA-7209)
MSK-118E SSR-7 (SA-7198)
MSK-118G SSR-B (SA-7217)
MSK-118H SSR-8 (SA-7234)
MSK-121E SSR-7 (SA-7236)
SSR-11 SSR-14 o '; L
,