ML20212Q886
| ML20212Q886 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/26/1987 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-87, REF-PT21-87-023-000 (NMP2L-0979), (NMP2L-979), PT21-87-023-000, PT21-87-23, NUDOCS 8702020401 | |
| Download: ML20212Q886 (4) | |
Text
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E MiB NIAGARA MOHAWK POWER CORPORATION /301 P; AINFIELD ROAD, SYRACUSE, N.Y.13212/ TELEPHONE (315) 474-1511 January 26, 1987 (NMP2L 0979)
Dr. Thomas Hurley, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Re:
Nine Mile Point Unit 2 Docket No. 50-410
Dear Dr. Murley:
We are hereby providing written notification in accordance with 10CFR21 regarding problems with General Electric supplied Agastat GP Series Relays.
These problems were originally identified at Nine Mile Point Unit 2.
In summary, several Agastat GP Relays used at Nine Mile Point Unit 2 have been found improperly seated in their sockets.
This condition may have been caused by inadequate original installation, workers coming into contact with the installed relays, or both.
The corrective actions already taken included establishing instructions for installation and testing to ensure the relays are properly seated.
Corrective actions in progress or to be taken include the following:
1.
Identify and locate Agastat GP Relays used in safety related applications for Nine Mile Point Units 1 and 2.
2.
Inspect and correct, if necessary, Agastat GP Relays used in safety related applications at Nine Mlle Point Units 1 and 2.
(Completion date - February 9, 1987) 3.
Reinspect once a month as described in item 2 above.
We will establish a variable preventative maintenance procedure for the reinspection.
The monthly frequency may decrease, if appropriate, based on an evaluation of the information provided by the inspections. Other corrective actions and the root cause of this problem are expected to be identified during reinspections.
If necessary, a comprehensive root cause analysis will be performed.
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a Page Two 4.
Revise the appropriate maintenance procedures to include the recently established instructions for installation and testing of the relays.
(Completion date - March 31, 1987) 5.
Include information related to this incident in appropriate training programs for electrical Maintenance personnel, Instrumentation and Control personnel, Quality Control personnel and Operators.
(Completion date - April 30, 1987)
In accordance with 10CFR21.21, attached is a report that describes this incident in more detail based on currently available information Very truly yours, NIAGARA MOHAWK POWER CORPORATION Senior Vice President DAC/pn3 2499G Attachment xc: Regional Administrator, Region I Ms. E. G. Adensam, Project Director Mr. W. A. Cook, Resident Inspector Project File (2)
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ATTACHMENT 10CFR21 REPORT ON AGASTAT GP RELAY SEATING DEFECT NINE MILE POINT UNIT 2 NIAGARA MOHAWK POWER CORPORATION I.
Description of Condition:
Niagara Mohawk Power Corporation found problems related to General Electric Agastat GP Relays in December of 1986. A representative of the GE San Jose Electrical Design Group was sent to the site to assist in the investigation. A relay was removed and examined.
This examination indicated that the relay was fully functional.
Inspection of panels that contain the relays in question showed that several relays were not properly seated. GE provided instructions that are now being used to properly seat the relays and verify that the relays are properly seated.
One problem with seating these relays in their sockets is that proper seating requires over 50 pounds of force. Additionally, the relays may appear to be seated after installation when, in fact, they are not.
Therefore, an objective test has been developed to verify that the relays are seated after installation.
The test includes using a 0.030 inch thick non-metallic feeler gauge between the relay and the socket; if the gauge does not fit in between, then the relay is adequately seated.
These relays are equipped with a wire retention clip or a retention strap.
If the retention equipment is installed, the relay will remain in place with up to lg vertical force.
It is unlikely that they could be vibrated loose.
However, installation of the retention device (strap or clip) does not ensure that the relay is properly seated.
The problem may be solely attributable to the original installation of the relays; that is, they were not fully seated when originally installed. Another cause of the problem has been posited as personnel inadvertently coming into contact with or setting equipment on the relays.
It is possible to unseat the relays by inadvertent contact.
In any case, it does not appear that adequate instructions for installation were available at the time of original installation.
These relays are used in safety related and non-safety related applications, and therefore, some are basic components.
Considering that they were purchased to meet safety related technical requirements and when received were not accompanied with adequately detailed information procedures necessary to ensure proper seating, it is Niagara Mohawk's opinion that the components are defective. However, the condition that was found in the field may not be solely attributable to this defect.
2499G i
II.
Evaluation of Substantial Safety Hazard:
Had the defect remained undetected, systems which would be relied upon for service would be potentially inoperable.
These systems could have been, but are not limited to, Residual Heat Removal, Control Rod Drive, Reactor Core Isolation Cooling System, and Reactor Protection System.
Niagara Mohawk's inspection results identified relays that did not meet inspection criteria, but these relays were found to be electrically functional. There are approximately 1200 of these relays in safety related uses at Nine Mlle Point Unit 2, and over 100 for Unit 1.
The exact number and location of relays is being determined.
This situation could have led to the inoperability of systems required for safe shutdown, emergency cooling, post-accident containment heat removal or post-accident containment atmosphere cleaning.
He have, therefore, concluded a substantial safety hazard exists.
III. Corrective Action in Progress or Planned:
1.
Identify and locate Agastat GP Relays used in safety related applications.
(Completion date - February 9, 1987) 2.
Inspect and correct, if necessary, Agastat GP relays at Units 1 and 2 used in safety related applications.
(Completion date - February 9, 1987) 3.
Reinspect once per month as described in item 2 above. We will establish a variable preventative maintenance procedure for the reinspection.
The monthly frequency may decrease, if appropriate, based on an evaluation of the information provided by the inspections.
Other corrective actions and the root cause of this problem are expected to be identified during reinspections.
If necessary, a root cause analysis will be performed.
4.
Revise appropriate maintenance procedures to include the recently established installation and inspection instructions.
(Completion date - March 31, 1987) 5.
Include information related to this case in appropriate training programs for electrical Maintenance personnel, Instrumentation and Control personnel, Quality Control personnel and Operators.
(Completion date - April 30, 1987) i i
2499G
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