ML20037D239
| ML20037D239 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 05/15/1981 |
| From: | Heider L VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.16, TASK-2.K.3.18, TASK-TM FVY-81-80, NUDOCS 8105220373 | |
| Download: ML20037D239 (2) | |
Text
V ERNONT Y AS K EE N UCLEAR POWER CORPOR ATION SEVENTY SEVEN GROVE sTREcT V
RUTLAND, URMONT 05701 RE PLY T Or ENGINEERING OFFICE ~
0 1671 WORCESTER ROAD -
F RAMINGH AM. M ass ACH UsETTs 01701 TELEPHONE Gl7-87 2 8100 FVY-81-80 2.C.2;l 4
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May 15, 1981 If I'IAY g g 08f A L>
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United States Nuclear Regulatory Commission
- 4rg, Washington, D. C.
20555 D
g Office of Nuclear Reactor Regulation k_ Tl ih Attention:
Darrell G. Eisenhut, Director.
Division of Licensing e
50-271)
References:
(a) License No. DPR-28 (Docket No.
(b) Letter, D. G. Eisenhut to All Licensees of Operating Plants, dated October 31, 1980 15, 1980 (c) Letter, VYNPC to USNRC, WVY 80-170, dated December B. Waters to USNRC, dated March 3,1981 (d) Letter, D.
(e) Letter, VYNPC to USNRC, FVY 81-56, dated April 3,1981 Submittal of Information on NUREG-0737, Item II.K.3.16, " Reduction of Challenges and Failures of Relief Valves" and Item II.K.3.18,
Subject:
" ADS Actuation" i
Dear Sir:
Vermont Yankee has completed its evaluation of inf ormation received from l
and hereby presents our response to the I
the BWR Owners's Group, Reference (c),
NUREG items as requested in Reference (b).
subje ct Item II.K.3.16 " Reduction of Challenges and Failures of Relief Valves" The basic objective of Item II.K.3.16 is to reduce the number of challenges to The approach taken in Reference (d) is to reduce the inpidence l
of stuck open relief valve events; to reduce causes of spurious blowdowns, and relief valves.
l to reduce the probability of safety /reifef valves sticking open when l
The experience base compiled by General Electric Company includes challenged.
For Vermont Yankee, two over 1,000 saf ety/ relief valve years of opera tion.in fewer isolation events, thereby candidate modifications will result One of these decreasing potential challenges to safety / relief valves.to 800 psig.
The involves lowering the MSIV pressure isolation setpoint second involves increasing the high steam flow isolation from 120 to 140 If found percent of rated steam flow. We are evalua ting these changes.
to Technical
)
acce ptable, they will be submitted as a proposed. change Specifications.
81052203'q3 f
L..
~
U. S. Nuclear Regulatory Co= mission ~
May 15, 1981 Attentgon: Da rrell G. Ei senhut. Director Page 2- _
3 Item II.K.3.18 Modifications of Automatic Depressurization System Logic"
~
This NUREG-0737 item requires a feasibility and risk assessment study to.be performed to determine if changes 'should be made to the Automatic 1
Depressurization System ( ADS). logic to optimize its operation.
the BWR Owners',. Group has completed a study which includes As discussed above, dircussion on several viable options. Four hardware modifications, along with retention of the current scheme, were considered.- These five option's were.
evaluated as to system performance, f easibility of implementation, cost of additional design and hardware and impact on plant operation..
I Vermont Yankee has completed review of the subject study and has concluded at this time that hardware changes are.not desirable and, in f act, are not required if the new procedures developed from the _ emergency procedure guldelines are implemented.- In addition, if any of the proposed changes were j
to be implemented, they would change the design basis of this system and the I
probability of existing design basis accidents.
Such a change would constitute an unreviewed saf ety question.
We trust the above supplied information is acceptable to you.
If you l
have further concerns or questions, please contact us.
1
- Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION
/
c L. H. Heider Vice President 1
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