ML20070D497
| ML20070D497 | |
| Person / Time | |
|---|---|
| Site: |  |
| Issue date: | 02/15/1991 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| CON-NRC-91-15 VPNPD-91-66, NUDOCS 9103010005 | |
| Download: ML20070D497 (3) | |
Text
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POWER COMPANY m w Mcwo b Poemwe+ w 53201 (454)2212 2 VPNPD 66 NRC 15 February 15, 1991 Mr. A. Bert Davis, Regional Administrator Office of Inspection and Enforcement Regicn III U. S. NUCLEAR REGULATORY COMMISSION 799 Roosevelt Road Glen Ellyn, IL 60317 Gentlement DQpKET NO.S 50-200 AND 50-1Q1 REPLY TO NOTICE OF VIOLATION INSPECTION REPORTS 50-266/90020 & 50-301/9001Q POINT BEACH NUCLEAR PLAliT UNITS 1 AND 2 This letter is in response to a Notice of Violation enclosed with your letter of January 16, 1991.
The Notice of Violation is associated with a routine safety inspection conducted by Mr. R.
Hasse and Mr. I. Yin during the period from October 22~,
1990 through January 2, 1991 and was included in Inspection Report 50-266/90020; 50-301/89030.
The violation identified.in the inspection report and described in the Notice of Violation involved the failure to properly perfoun a post-modification test'for Modification 88-172, " Add Ic.cumulators to the Instrument Air Supply-to the Crossover Steam Dump Valves."
The acceptance criteria for this test were-based on the valve manufacturer's information that the crossover steam dump valves could be operated at 30 psig air pressure..The-final operational i
test, however, was conducted at 60 psig air pressure, and-the accumulator leak rate was not documented at 60-psig air pressure.-
Wisconsin Electric agrees that the conditions described in the Notice of Violation have been prope.rly characterized as a Severity Level IV violation.
The subject modification involved the ins'tallation-of a check valve on the-main instrument air supply line.to the crossover' steam' dump valve and an accumulator downstream of the check valve. -This modification was. designed to ensure that an adequate air supply was available to operate the steam dump valves upon a loss of instrument air.
After the-installation of this modification, a 19103010005 910215 l
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Mr. A. Bert Davis February 15, 1991 page 2 post-modification test was planned to ensure that there was minimal air leakage downstream of the check valve and that the air supply in the accumulators was sufficient to operate the steam dump valves with instrument air isolated from the accumulator. The post-modification test was written for, and the acceptance criteria were based on, the premise that the optimum pressure for steam dump valves operation was 30 psig, as specified by the valve manufacturer.
The instrument air supply to the steam dump valves was normally supplied through a pressure reducing valve at 40 psig.
During the post-modification test, the accumulator air leakage was checked satisfactorily at 40 psig air pressure.
Two of the steam dump valves, however, did not fully open during the 40 psig operational test.
At the time of the test, the Duty Shift Supervisor (DSS) responsible for. conducting the post-modification test was unable to contact the responsibic engineer for the modification for further guidance.
After conferring with the maintenance personnel involved with the test, the DSS decided to adjust the pressure regulator and raise the accumulator pressure to 60 psig for the test.
At 60 psig accumulator air pressure, the dump valves worked properly with instrument air isolated from the accumulator.
Since the valves had operated properly at 60 psig, site engineering personnel directed that the pressure regulator _be set at 60 psig.
The DSS then concluded that the test had been completed satisfactorily.
The DSS did not understand that the acceptance criteria had been based on a 30 psig test, that the test procedure would have_to be' rewritten for the 60 psig test, and that the. leak-rate check would have to be repeated at-60 psig.
This-has-subsequently _been discussed with the-individual and he understands the requirements to perform this work in strict accordance with approved test procedures.
To prevent recurrence of similar events the Superintendent-of Operations has issued a Night orders Entry stressing the need for procedure changes in strict accordance with administrative procedures for this type of testing.
.In. addition, prior to the next scheduled outage, the engineers'in the affected work group will have a meeting to discuss this event, their responsibilities
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regarding post-modification testing, and proper control of-revisions to testing procedures..
l Using. revised acceptance criteria,1a new accumulator leak rate test
.and a-dump valve operational test of the steam dump system will-be performed-by March 4~,
1991.. The proper operation:of-the crossover j
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steam dump valves will then be checked quarterly with instrument
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Mr. A. Bert Davis February 15, 1991 Page 3 i
l air being supplied to the accumulator.
Additionally, there will be an annual test to determine the air pressure required to operate the most restrictive valve.
This pressure will ba trended and maintenance will be performed on any valve which does not operate within the acceptance criteria established in the initial testing.
Your January 16, 1991, letter also requested that we respond'to an open item from the inspection report regarding the concern with the apparent degradation of the crescover steam dump valvec.
Ac noted in the previous paragraph, we will be trending the change in the operating pressure for the most restrictive valves as a monitor of further valve degradation.
Our response to the initial 1988 test of these valves, when six of the eight valves failed to open upon loss of instrument air, included the examination of-one of the valves.
At that time we could determine no basis for why the valve did not open as expected.
During the spring 1991 Unit i refueling outage, scheduled to begin on April 5, 1991, we will disassemble and examine a second valve to determine why the valves are not-operating as originally designed.
A representative of the valvo manufacturer will be requested to assist us in this investigation.
Particular emphasis will be placed on examination of the relationship between the pilot valve function and opening of the steam dump valve.
We will notify you of our findings following the-outage.
If you have any questions concerning this-information, please contact us.
Very truly,yours,
/ M ce a,e C.
W.
F'ayo Vice President Nuclear Power Copy to:
NRC Resident Inspector Documant Control Desk 1
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