ML18038A192
| ML18038A192 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 07/31/1986 |
| From: | Lempges T NIAGARA MOHAWK POWER CORP. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NMP-18422, NUDOCS 8608080140 | |
| Download: ML18038A192 (4) | |
Text
NIAGARAMOHAWKPOWER CORPORATION
.)eII'W, NIAGARA I I MOHAWK NMP-18422 THOMAS E. I.EMPGES VCEPRESOENT~ OENEMTON 300 ERIC SOULEVARD WCST SYRACUSE, N. Y. l3202 July 31, 1986 Dr. Thomas E. Murley Regional Administrator United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylv'ania
- 19406,
Subject:
Response
to Inspection Report No. 50-220/86-10 Sir:
This letter is in response to the Notice of Violation enclosed as Appendix A to Inspection Report No. 50-220/86-10.
The violation concerns placing the in-core Hydrogen Water Chemistry Sampling Line in service prior to performing the required hydrostatic pressure test.
This event has been reported in Licensee Event Report 86-20.
Due to an incorrect sequence on the contractor in'stallation procedure, the hydrogen water chemistry incore sampling line was placed in service prior to performing the hydrostatic leak test, as required by ASME Section III 1980 Edition, Subsection NC with the Summer 1982 Addenda.
Welding was performed on the sample line after the hydrostatic leak test and subsequently, a pinhole leak developed in the sample line outside of primary containmeng while the reactor was at power and pressurized.
At the time of discovery of the leak, the reactor was in, the process of being shutdown due to an unrelated problem.
Following the completion of the reactor shutdown, a cooldown was initiated to lower reactor coolant temperature to facilitate disconnecting the sample line between the reactor vessel and the source of leakage.
A drywell entry was made and the sample line was isolated from the reactor vessel by removing a Swagelok connector and capping the open ends of the line.
The primary containment penetration and the disconnected line were local leak rate tested to verify pressure integrity.
e Repairs were effected on the leaking portion of the sample line on July 9-11, 1986 during a plant forced outage.
The damaged section of sample line was removed and replaced with new pipe.
To ensure that all welding on the line was completed prior to the final hydrostatic leak test, additional administrative hold points were incorporated into the contractor's repair procedure.
In addition, a new hydrostatic test procedure was written which included verification of the completion of all welding as a prerequisite for commencing the test.
The repaired sample line was successfully pressure tested on July ll, 1986.
Following the successful completion of the 8608080140 S6073i PDR ADOCN, 05000220 Poa
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NMP-18422 hydrostatic leak test on the sample line and the local leak rate test on the penetration, the sample line was reconnected to the reactor vessel by replacing the previously removed Swagelok connector.
The connector was inspected for leakage during the next reactor startup on July 14, 1986 with the reactor pressurized at 900 psi.
No leakage was noted.
The cause of the violation was an inadequate field installation procedure which allowed the sample line to be placed in service without the necessary hydrostatic leak test being completed.
To prevent recurrence of this event, the requirements and specifications of the ASME code regarding hydrostatic leak testing were reviewed with the plant engineer responsible for this modification and will be reviewed with plant engineers and QA personnel responsible for system pre-operational and hydrostatic testing.
Xn addition, NMPC design engineering personnel will now specify the code requirements for hydrostatic testing, including the test sequence and boundaries.
Very truly yours, 8 ~~
Thomas E. Lempges Vice President Nuclear Generation TEL/meed
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