ML20154L987
| ML20154L987 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 08/12/1988 |
| From: | Larson C NORTHERN STATES POWER CO. |
| To: | Axelson W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8809270016 | |
| Download: ML20154L987 (2) | |
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Northern States Power Cornpany 414 Niconet Man Minneapoks. Mennesota 55401 Teephone (612) 330 5500 W L Axelson, Chief Reactor Projects Branch 2, Region III U S Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 PRAIRIE ISLAND NUCLEAR GENERATING P1ANI Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Response to Inspection Reports 50 282/88008(DRP) and 50-306/88008(DRP)
Inadvertent Substation Breaker Operation Your letter of July 7,1988, which transmitted Inspection Raports 50-282/88008 and 50-306/88008 requested additional information regarding substat on breaker actuation tne events surrounding the May 25, 1988 i
and the status of the substation work control process.
The following is s-itted in response to that request.
On May 25, 1988, Breaker 8Ht7 and its associated motor operated dis-connects (MOD's) opened due to work being :onducted in the substation.
The work that was in progress was a continuatiot,of our efforts to improve the accuracy of substation drawings.
Specifically, the work-man was wire checking the panels in the substation control house.
During the performance of this work a terminal post on a barrier term-inal strip failed mechanically and came loose from the strip.
This wire shorted to an adjacent terminal causing breaker 8H17 and its associated MOD's to open at 1033.
The worker immediately contacted NSP System Operations who was already in contact with the Prairic Island Shif t Supervisor.
The worknan landed the loose wires on an adjacent geod terminal strip and the MOD's and 8H17 were closed at 1049.
j Subsequent investigation revealed that the Prairie Island Shift Super-visor was not aware that wice checking was in progress on the date of the occurrence.
Since the work involved was to take place over a long period of time (apprcximately a year), an agreement had been reached I
between the Plant and the work department to deviate from the normal practice of requiring the workman to cbtain a key to the substation each day.
The workman was issued a key with the understanding that each day, prior to commencing work, he would call the Shift Supervisor and inforn. him that the wire checking was about to commence and what 8809270016 880312
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-e W L Axelson, NRC, RIII Nodhem States Power Company August 12, 1988 Page 2 equipment would be affected The workman was also to inform the Shift supervisor when work was completed for the day.
This agreement was documented on a Prairie Island Operations Note.
On May 25, 1988 the required notification of the Shif t Supervisor was not made prior to commencing work.
After reviewing the circumstances surrounding the actuation of 8H17, this policy was canceled.
In the future, the key to the substation must be obtained on a daily basis with the permission of the Shift Supervisor prior to the commencement of work. Additionally, a Request for Outage detailing the equipment to be wire checked is now being issued to ensure understanding of what equipment could be affected.
Also, wire checking for the unit generator output breakers has now been restricted to unit outages. As an additional measure, to ensure that plant management is aware of work in progress in the substation, this work is now listed in the Daily Planning Review and covered during the daily staff meeting.
Substation errors have been of concern both to NSP nuclear generation management and the Prairie Island Senior NRC Resident Inspector.
To address these concerns, control of work processes in the Prairie Is-land and Monticello substations is being upgraded through the develop-ment of substation work process directives. These directives are currently in draft form and undergoing final review.
It is antici-p ad that they will be approved and issued by October 1, 1988.
'ning in the new processes and full implementaticn will occur with-t 1x weeks of approval.
~hg C E Lars Vice President Nuclear Gen ration c: Regional Administrator III, NRC NRR Sr Project Manager, NRC Sr Resident Inspector, NRC G Charnoff