ML20090E113
| ML20090E113 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/09/1984 |
| From: | Murphy W VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| FVY-84-87, NUDOCS 8407190292 | |
| Download: ML20090E113 (7) | |
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VERMONT YANKEE NUCLEAR POWER CORPORATION FVY 84-87 R D 5, Box 169. Ferry Road, Brattleboro, VT 05301
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p ENGINEERING OFFICE 1671 WORCESTER ROAD FRAMINGHAM. MASSACHUSETTS 01701 July 9, 1984 TELEPHONE 617-872-8100 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention:
Office of Nuclear Reactor Regulation Mr. Domenic B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing
References:
a)
License No. DPR-28 (Docket No. 50-271) b)
Letter, USNRC to VYNPC, dated 5/3/84 c)
Letter, VYNPC to USNRC, dated 2/7/84
Dear Sir:
Subject:
Snubber Technical Specifications In response to your request [ Reference b)], the following information regarding snubber Technical Specifications is provided:
Item 1-The STS Table footnote contains.the provision, " Snubbers may be added to safety related systems without prior License Amendment to Table provided that a revision to Table is included with the next License Amendment request." Your proposed TS 3.6.I.4 contains the provision for adding or deleting snubbers and the word " subsequent" is used instead of "next".
Recently approved Technical Specifications for Near Term Operating Licensees (NT0L's) included the following condition for such deletion:
"In lieu of any other report required by Specification 6.9.1, at least 15 days prior to the deletion of any listed snubber, a Special Report shall be prepared and submitted to the Commission in accordance with Specification 6.9.2 evaluating the safety significance of the proposed snubber removal."
If your proposed Technical Specification contains the deletion provision, include the recently approved NTOL Technical Specification condition.
Delete " subsequent" and insert "next" or if the word " subsequent" is used instead of "next", your proposed Technical Specification should specify a time frame (e.g., within 90 days).
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' U.S. Nuclear Regulatory Commission
- July 9,1984 Page 2 VlillMONT YANKI!!! NUct.tsAlt Pow 1?It COltPOltATION
RESPONSE
Vermont Yankee intends to delete the Snubber Table from our Technical Specification in accordance with the USNRC Letter to All Power Reactor Licensees, dated May 3, 1984. This item, therefore, is no longer applicable.
Item 2 The STS visual acceptance criteria 4.7.9b contains the provisions,
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" Snubbers which appear inoperable as a result of visual inspections may be determined OPERABLE for the purpose of estcblishing the next visual inspection interval, providing that (1) the cause of the rejec-tion is clearly established and remedied for that particular snubber and for other snubbers that may be generically susceptible; and (2) the affected snubber is functionally tested in the as-found condition and determined OPERABLE per Specifications 4.7.9d or 4.7.9e, as applicable." Your proposed TS 4.6.I.1.b contains the term "and/or" preceding the (2) and this provides an additional option. The "/or" should be deleted from your proposed TS.
Your proposed TS 4.6.I.1.b paragraph on page 110c can be deleted here since it is more appropriate under TS 4.6.I.1.c and it is repeated there. The paragraph contains the provision, "The scope of this engi-neering evaluation shall be consistent with the licensee's engineering judgement and may be limited to a documented visual inspection of the supportedcomponent(s)."
If you elect to leave the paragraph here delete this provision or revise the phrase " engineering judgement" to
" documented engineering evaluation", or " documented engineering judgement".
RESPONSE
Vermont Yankee will delete the "/or" and delete the paragraph discussing evaluation by engineering judgement.
Item 3 The STS 4.7.9b contains the visual acceptance criteria condition, "However, when the fluid port of a hydraulic snubber is found to be uncovered, the snubber shall be determined inoperable and car.not be determined OPERABLE via functional testing for the purpose of establishing the next visual inspection interval." Your proposed TS-4.6.1.1.b contains.the provision to determine OPERABLE via functional test.
Recently approved TS for NT0L's include the following condition for determining OPERABLE, "When a fluid port of a hydraulic snubber is found to be uncovered, the snubber shall be declared inoperable and
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b shall not he'determindd OPERABLE via functional test unless the test is st'arted with the piston in the as-found setting, extending the
_ piston rod in the tension mode ~ direction."
If your proposed TS is to coritain the furictional test provision for determining OPERABLE,
-include' this recently approved NT0L condition.
RESPONSE ~
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Verr 5nt Yankee will' revise our application for license amendment to incor-porate the suggisted specification.
~ Item 4 The STS 4.7.G functional test does not exempt snubbers of greater than 50,000 lb, whereas your pre, posed TS 4.6.I.1.c contains the provi-sion, " Snubbers of ratsd capacity, greater than 50,000 lbs. need not be
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functionally tested." One of.the objectives of the STS was to elimi-
'nate this 50,000 lb. arbitrary limit on testing, therefore, your pro-posed TS should be revised to remove the exemption.
If a reasonable
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time delay interim exemption is needed, it should be requested and you should provide reasons-for its need (e.g., to obtain larger capacity i
testequipment,etc.).. Your proposed TS should define the end date of
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] the exemption,so it will be self-cancelling.
RESPONSE; l
- Vermont Yankee currently has in place a program for testing snubbers which exceed the capacity of our testing machin?.
Accomplishment of this testing involves:
- 1) checking and/or setting proper. lockup and bleed velocity of the snubber valve; 2) che.cking for free stroke of the cylinder; and 3) checking the pressure retaining cipability of the cylinder.
-This program is based on a vendor supplied procedure which requires mounting the valve assembly from the snubber which is too large for the testing machine on to a 4" bore snubber. The proc'edure provides a calculation of equivalent velocities and forces between the' 4" snubber and the large snubber.
A correlation is then made to determine the appropriate acceptance criteria.
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Additional testing is done' to verify the free stroke and pressure capabilities of the snubber.
It is important to note that Vermont Yankee has only one snubber in this category. Coqsidering the minimun number of snubbers involved and the fact that c
we have a program in place that meets the intent of the specification we cannot justify the purchase of a larger capacity testing machine. We will clarify the exemption in our proposed TS to reflect the testing performed.
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'U.S. Nuclcar Regulatory Commission July 9, 1984 Page 4 ViiltMONT YANKl?E NUCLitAtt l'oweit Colu'oltATioN Item 5 The STS 4.7.9c contains the functional test condition, "For Each
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snubber that does not meet the functional test acceptance criteria of Specification 4.7.9d or 4.7.9e, an additional 10% of that type of snubber shall be functionally tested." Your proposed TS 4.6.I.1.c contains the provision for only testing an additional "5%".
The 5%
should be revised to 10%.
RESPONSE
Vermont Yankee will revise the percentage from "5" to "10".
Item 6.
The STS 4.7.9c contains the functional test condition, "At least 25%
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of the snubbers in the representative sample shall include snubbers from the following three categories:
1.
The first snubber away from each reactor vessel nozzle; 2.
Snubbers within 5 feet of heavy equipment (valve, pump, tubine, motor,etc.);and 3.
Snubbers within 10 feet of the discharge from a safety relief valve".
If the 25% sample is deleted, as is the case in your proposed TS, your TS or TS Bases should describe the STS 4.7.9c representative sample, as follows:
"The representative sample selected for functional testing shall include the various configurations, operating environments and the range of size and capacity of snubhers."
RESPONSE
The requirements contained in Standard Technical Specifications assume that plants have hundreds, or thousands, of snubbers installed. At Vermont Yankee, we have 57 snubbers. Considering that 10%, or 6 snubbers, are required to be func-tionally tested each refueling cycle, it is impossible to meet the standard Technical Specification r. quirements because the small number of snubbers in the sample would not be sufficient to encompass all the "various configurations, operating environments and the range of size and capacity of snubbers."
The proposed change, as submitted requires that a " representative sample" be tested during each cycle; we feel this is sufficient.
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Item 7 Your-proposed TS 4.6.I.1.c regarding functional tests contains the
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provision, "If any snubber selected for,functionai~ testing either fails to lock up nithin the capability of the testing machine," etc.
The phrase "within the capability of the testing machine" should be deleted from your proposed TS.
If a reasonable time delay _ interim exemption is needed, it sho'uld be requested and you should provide reasons for its need (e.g., to obtain larger capacity testing equip-ment etc.).
Your proposed TS should define the end date of the exemption so it will be self-cancelling.
RESPONSE
Vermont Yankee will delete the words "within the capability of the testing machine" from our proposed change.
See Response to Item #4 for additional information.
Item 8 Your proposed TS 4.6.I.2.c, functional test, last paragraph contains
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the provision, "The scope of this engineering evaluation shall be con-sistent with the licensee's engineering judgement and may be limited to a documented visual inspection of the supported component (s)."
Delete this' sentence, or the phrase " engineering judgement" should be revised to " documented engineering evaluation" or " documented engi-neering judgement."
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RESPONSE
Vermont Yankee will revise the sentence to require a " documented" judgement or evaluation.
Item 9 Your_ proposed TS does not include snubber service life monitoring..
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Your reference > (4) reasons for not including this provision were that the TS' intent was satisfied through the plant's preventive maintenance requirements of determining failure trends and that other more impor-stant TS do not require this type program.
During the reference (3}
inspection, there was lack of documente,d evidence of a preventive maintenance program for failure trending; Neither'was there criteria for detennining service life in your maintenance procedure and recor'ds, and additionallyr there was difficulty in, determining which were the high capacity' snubbers.
Concerning your referende (4) com-ment that other TC ' areas do not require this type. program, it is
' pointed out that other equipment undergoes more frequent inservice tgsting and other methods to verify operability.
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'U.S. Nuc1 car Rigulatory Commission July 9,1984 Page 6 VEllMONT YANKEE NUCLEAll POWElt COltI*OltATION In view of the above, the staff concludes that service life monitoring coverage should be in your TS.
RESPONSE
We have reviewed our existing administrative program and cannot agree with
'the conclusions drawn by the NRC Inspectors.
The results of testing, inspec-tions and/or repairs are documented and evaluated. The acceptability of this approach is clearly demonstrated by our past experience.
In instances where failures were anticipated or occurred (e.g., seal degradation problems), preven-tive maintenance was performed as necessary on suspect snubbers prior to failure..It should also be noted that VY has not experienced a functional test failure on the 10% required sample since 1978. Additionally, it has been our practice to rebuild 10% or more of our snubbers during each refuel outage as part of our preventive maintenance program.
The NRC statement indicating that, because snubbers do not receive frequent in-service inspection or other methods to verify operability does not justify having a specific service life monitoring problem in Technical Specifications.
That concern is addressed by the variable inspection frequency already contained in the specifications.
Vermont Yankee already has in Specification 6.5 a requirement to have detailed. procedures in areas including surveillance, testing
-and preventive maintenance. We continue to feel that this is sufficient.
Item 10-Your proposed TS Bases last paragraph phrase of " tested once each refueling cycle" is not per the STS. The phrase should be revised to the STS phrase of " tested during plant shutdowns at 18 month intervals" or use your existing TS defined term " tested during each operating Cycle."
Your proposed TS Bases should include service life monitoring (see Item 9).
RESPONSE
Vermont Yankee will substitute the Technical Specification defined term of
" operating cycle".
See our response to Item #9 for our position on service life monitoring.
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"U.S. Nuclear R gulatery Commission
. July 9,-1984 Page 7 VEHMONT YANKEE NUCLEAR POWER CORPORATION It is presently our plan to submit a revision to Reference c), which incor-
-porates the changes discussed in our response to Items 1 through 10 above by October 1984.
Should you have any additional questions or comments regarding this infor-mation, do not hestitate to contact us.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION
'"l' AM" - -
Warren P.
urphy Vice President and Manager of Operations WPM /dm
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