ML19211A321
| ML19211A321 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 10/29/1979 |
| From: | Moody D VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-02, IEB-79-2, NUDOCS 7912170365 | |
| Download: ML19211A321 (2) | |
Text
7E m._.
VERMONT YAN KEE NUCLEAR POWER CORPORATION i
SEVENTY SEVEN GROVE STREET RUTLAND, VERMONT 05701 R EPt.Y TO:
October 29, 1979 ENGINEERING OFFICE TURNP!KE RO AD WESTBO RO. M ASS ACHUSETTS 015 81 TELEPHONE 617 364 9011 United States Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, PA 19,406 Attention:
Mr. Boyce Grier
References:
(a) Docket 50-271 (License No. DPR-28)
(b) Vermont Yankee Let'er to USNRC, WVY 79-85, dated 7/31/79 (c) I&E Bulletin No. 79 v2., Revision 1, Supplement 1
Dear Mr. Grier:
Subject:
Anchor Bolt Replacement at Vermont Yankee Reference (b) described the anchor bolt replacement program at Vermont Yankee.
In that letter we co=mitted to complete the replacement program within three weeks following plant startup.
Since that time we have had approximately twenty engineering support personnel and one hundred crafts people involved in the inspection, replacement and, where necessary, re-design of supports in fulfillment of the program requirements, Approximately 450 supports containing 2500 anchor bolts require anchor bolt replacement. We anticipate that approximately one-half of the total number of supports will be completed by the end of the refueling outage.
This figure includes all of the supports inaccessible during plant operation and all of the resonant supports.
There are several reasons for the lower than hoped for completion rate:
1.
The original completion date was established based on a small sample size for judging production rate; 2.
A final tally on the total number of supports and anchors was not available at that time; 3
Installation of torus modifications interferred with work in the lower level of the reactor building; 1593 001
.O
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United States Nuclear Regulatory Commission October 29, 1979 Attention:
Mr. Boyce Grier
?nge 2 4.
Self-imposed, conservative engineering requirements, which require welding washer plates to the support baseplates, delay the completion of a support; 5.
Support accessibility is extremely difficult in some locations.
Subsequent to our Reference (b) commitment the NRC issued Reference (c),
which stated that plant op6 ration could continue or resume as long as supports and anchor bolts had a factor of safety of two (2) or greater.
Vermont Yankee established with the NRC early in the program that all supports and anchor bolts at Vermont Yankee had a factor of safety well in excess of two; only in the case of resonant lines did the factor of safety approach two.
Replacement of anchor bolts in all such lines was completed prior to plant shutdown.
Thus, in light of the revised NRC criteria in Reference (c), Vermont Yankee is modifying its previous commitment. We will continue with our anchor bolt replacement program following plant startup until all anchor bolts are replaced. We anticipate completion on or before March 1, 1980.
Very truly yours, VERMONT YANZEE NUCLEAR POWER CORPORATION
%.t h Q D. E. Moody Manager of Operations dmp
- 593 002
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