ML20210F867
| ML20210F867 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 02/02/1987 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-87, REF-PT21-87-029-000 (NMP2L-0989), (NMP2L-989), PT21-87-029-000, PT21-87-29, NUDOCS 8702110180 | |
| Download: ML20210F867 (5) | |
Text
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." P NIAGARA MOHAWK POWER CORPORATION /301 PLAINFIELD ROAD. SYRACUSE, N.Y.13212/ TELEPHONE (315) 474-1511 February 2, 1987 (NMP2L 0989)
Dr. Thomas E. Murley Regional Administratcr U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Re:
Nine Mlle Point Unit 2 Docket No. 50-410
Dear Dr. Murley:
In accordance with the requirements of Part 21 of the Commission's regulations, Niagara Mohawk is submitting a written report of a defect in the design of a basic component.
Initial notificction of this defect was made to the Nuclear Regulatory Commission's Mr. J. Linville by telephone on January 23, 1987.
The attached report provides the information required by 10CFR21.21.
Very truly yours, NIAGARA M0 HAWK POWER CORPORATION C. V. Mangan Senior Vice President KBT/pns 2524G xc: Director, Office of Inspection and Enforcement Project File (2) 8702110180 870202
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b NIAGARA MOHAWK POWER CORPORATION Report of Deviation, Defect, or Failure To Comply (1) Name and address of the individual or individuals informing the Commission:
The Commission was informed by telephone on January 23, 1987, by Peter E. Francisco, Lead Licensing Engineer.
(2)
Identification of the facility, the activity or the basic component supplied for such facility or such activity within the United States which fails to comply or contains a defect:
Improper electrical manhole duct seal design at Nine Mile Point Unit 2.
(3)
Identification of the firm constructing the facility or supplying the basic component which fails to comply or contains a defect:
The electrical manhole seals were designed and installed by the Stone and Webster Engineering Corporation.
(4) Nature of the defact or failure to comply and the safety hazard which is created or could be created by such defect or failure to comply:
Electrical Manhole #5 is located at EL 244'-0" in the decontamination building. Safety-related electrical duct banks and conduit run from this manhole to the control building and to the service water pump bays.
The seals on the duct bank and conduit are Dow Corning 3-6548 (foam) rated at 2 psi.
There are no additional seals at the control building end of the duct banks.
There are elastomer (with caulk facing) seals at the service water pump bay end of the conduit.
However, these seals are only designed to work against pressure from the pump bay side.
A failure of circulating water piping could flood the turbine building pipe tunnels.
The water could eventually flood Manhole #5 since the manhole covers are not watertight.
The pressure at the bottom of the manhole could cause the duct bank seals to fall. This failure would allow the flood waters to travel through the duct banks and conduit to the control building and the service water pump bays.
The resulting flooding in the control building could disable Category I electrical equipment that is not designed for submergence.
The resulting flooding in the service water pump bays could disable the safety-related service water pumps.
Loss of this equipment would adversely affect the operation of the plant and the safe shutdown capability.
252dG
4 (5) The date on which the information of such defect or failure to comply was obtained:
A potential problem was initially identified on December 29, 1986. As a result of a preliminary analysis by Stone and Webster which we received on January 21, 1987, Niagara Mohawk determined that degradation of such safety-related equipment represents a major reduction in the degree of protection provided to the public health and safety, and accordingly could have created a substantial safety hazard.
(6)
In the case of a basic component which contains a defect or falls to comply, the number and location of all such components in use at, supplied for, or being suppled for one or more facilities or activates subject to the regulations in this part:
He have not identified any other components at Nine Mlle Point U11t 2 subject to this failure. At this time, we know of no other facilities potentially having this defect.
(7) The corrective action which has been, is being, or will be ta',en; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to complet! the action:
The manhole covers have Deen redesigned to prevent flooding of the manhole.
The new manhole covers will be installed prior to initial criticality.
(8) Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasers or licensees.
l Not applicable.
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