ML19208D685

Submits Rept on Progress Re TMI Bulletin 79-14, Seismic Analysis of As-Built Safety-Related Piping Sys. Reverifies That Valve & Operator Weights Used in Computer Analyzed Seismic Analyses Are Correct

ML19208D685
Person / Time
Site:	North Anna
Issue date:	08/31/1979
From:	Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
552C-070279, 552C-70279, NUDOCS 7909290313
Download: ML19208D685 (2)

Text

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ffQ Go-3w Vp viRoiNia uECTRIC AND POWER COMP ANY, RICHMONO, VIRGINi A 23261 August 31, 1979 Mr. James P. O'Reilly, Director Serial No. 552C/070279 Office of Inspection & Enforcement PSE&C/CGC:mac: wang U. S. Nuclear Regulatory Commission Region II Docket Nos. 50-338 101 Marietta Street, Suite 3100 50-339 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

This letter is a report of our progress concerning NRC I.E. Bulletin 79-14.

In our letter of August 1, 1979 (S.N. 552/070279), we stated that we would re-verify '. hat valve and operator weights used in computer analyzed seismic analyses are correct; this re !erification would be accomplished by determining weights used in the analyses and comparing them to weights given on design documents. The status of this effort is sumarized below.

Table 1 (attached) is a numerical summary. Based on Unit 2 data, we have determined that approximately one half of all the computer analyzed seismic MSK's are acceptable and require no further review. Apprcximately one half of the remaining MSK's require valve weight verification from vendors. Based on results to date we expect that about one half of the valves requiring vendor weight verification will be compatible with the analyzad weight. Therefore, we expect roughly 65 percent of the total number of MSK's investigated will be acceptable without any detailed evaluation. Of those MSK's requiring further evaluation, none has to date been identified as a nonconformance. Should a nonconformance be found, we will comply with the Bulletin supplement of August 15, 1979 and imediately make an initial engineering judgement (within 2 days), followed by an analytical engineering evaluation (within 30 days) for Unit 1; for Unit 2 we will comply with the Bulletin as specified for licensees or permit holders as the case may be when the nonconformance is identified. Our target date for completing this valve and operator weight verification program and submitting our final report is October 30, 1979, which satisfies the Bulletin's requirements.

If you have any questions, plea contac this office. ,

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IE Bulletin 79-14

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TABLE 1*

SUMMARY

OF VALVE AND OPERATOR WEIGHT REVIEW Unit 1 U_ nit 2 Total Number of Computer-Analyzed 145 143 Seismic MSK's**

Tota' Number of MSK's with Acceptable -

77 Revi?w Number of MSK's containing no valves 46 37 Number of MSK's acceptable per previous 5 2 I.E. Bulletin 79-04 review Number of MSK's with va~ a weights 36 within 10% of actual weight Number of MSK's acceptable after -

2 engineering evaluation Total Numbc of MSK's Requiring -

66 Evaluation or Vendor Verification of Valve Weights Number of MSK's r juiring vendor valve 77 33 weight verificatioa before review can start Number of MSK's identified which require -

33 further evaluation

• This Table is a summary of the computer analyzed seismic MSK's. For Unit 1, 17 MSK's have not been reviewed to the point where they can be entered on the Table, which accounts for the blanks on the Unit 1 side.

This Table only represents data for MSK's analyzed originally by Stone &

Webster. Data for MSK's (20 total) analyzed originally by others (Teledyne and Nuclear Services) is still being developed and is not in-cluded on this Table.

• • An MSK is an isometric piping drawing.

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