ML19253A695
| ML19253A695 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 08/02/1979 |
| From: | Moody D VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 79-86, NUDOCS 7909110011 | |
| Download: ML19253A695 (2) | |
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VERMONT Y AN KEE NUCLEAR POWER CORPORATION J
SEVENTY SEVEN GROVE STREET B.4.2.1 RuTt.Aso, VERMONT 05701 WVY 79-86 REPLY TO:
ENGINEERING OFFICE TURNPlKE RO AD WEST BORO, M ass ACHUSETTS 01581 August 2, 1979 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attention:
Mr. Boyce H. Grier
References:
(a) License No. DPR-28 (Docket 50-271)
(b) USNRC letter to VYNPC dated July 2, 1979; IE Bulletin 79-14
Dear Mr. Grier:
Subj ec t:
IE Bulletin 79-14; Seismic Analysis for As-Built Safety Rei c d Piping Systems Approximately one year ago, Vermont Yankee initiated a program to update the seismic design documentation for safety related piping.
This program was initiated because we were unable to extract usable informatica from the archive files.
Our program plan was as follows:
1.
Take design record piping isometrics and code them into the computer as a geometry input; 2.
Verify as-built geometries and support location; 3.
Re-analyze critical piping systems using actual amplified response spectra input rather than using " Robinson Fix" multipliers to static analyses upon which plant design is based; 4.
Issue new design data books for critical systems; 5.
With the issuance of IE Bulletin 79-02 the program was expanded to include re-analysis of baseplates for flexibility using the newly calculated support loads.
790900O11Q o. ~,. y U S) ( f.e Qat
United States Nuclear Regulatory Commission August 2, 1979 Attention:
Mr. Boyce H. Grier Page Two At the completion of plant construction and prior to startup of the facility in 1971, the architect-engineer for Vermont Yankee conducted a complete hanger verification program in which as-built support locations and design were compared with design drawings.
In addition, an independent third party review by an independent consultant was conducted of selected safety related piping.
This review consisted of a geometry check, independent stress analysis, support design review and support location check.
Thus, although the review was not conducted within the past twelve months, a review was, nevertheless, conducted after plant construction was completed.
We believe this satisfies the intent of the subject Bulletin.
Recently, additional checking (in the Bulletin 79-02 effort) of seismic support locations and piping geometry against drawings, has revealed that minor variances in seismic support locations exist.
These differences between hardware and drawings were reviewed by the architect-engineer before plant start-up and, in his j udgement, had no impact on plant design safety factors or safety operation.
Since we have found these minor discrepancies in piping and hanger configurations, we are accelerating our ef forts of re-checking all systems and plan to up-date isometrics to the current as-built condition to be used in our re-analysis of critical piping systems at Vermont Yankee.
Vermont Yankee will shutdown in mid-September for a six week refueling outage.
By the end of that outage we will have completed our inspection of all safety related piping for support location, drilled-in anchor bolt installation and piping geometry.
We will submit a written report within thirty days after plant startup.
We believe the previous inspection efforts, as well as our planned program, satisfies the intent of the subject Bulletin.
Should you have any questions, or require additional information, please feel free to contact us.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATT N 4
h D !E. Moody Manager of Operations dmp o - ). -- 3t r% U L)
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