ML20010H765
| ML20010H765 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 09/22/1981 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-81 10CFR-050.55E, 10CFR-50.55E, PLA-930, NUDOCS 8109290275 | |
| Download: ML20010H765 (3) | |
Text
{{#Wiki_filter:t 1.t r-J 3 g,g f @ Pennsylvania Power & Light Company Two North Ninth Street
- Allentown, PA 18101
- 215 / 770L5151 Norman W. Curtis Vice President-Engineering & Construction-Nuclear 215 / 770-5381 September 22, 1981 Mr. R. C. Haynes
[' Director, Region I [$' 'l Lk U. S. Nuclear Regulatory Commission L7 4 -{ ggpO O /$gfg 631 Park Avenue King of Prussia, PA 19406 8' g e p SUSQUEHANNA STEAM ELECTRIC STATION /h-h INTERIM REPORT OF A POTENTIALLY REPORTABLE DEFICIENCY INVOLVING AGASTAT 'GP' RELAY BASES ERs 100450/100508 FILES 840-4/821-10 PLA-930 Dear Mr. Haynes This letter serves to provide the Commission with an interim report of a potentially reportable deficiency involving Agastat 'GP' relay bases. The electrical integrity of the wire term.i ations on the relay bases could be adversely affected in cases where the defect exists. Mr. L. Narrow of NRC Region I was advised of the problem by Mr. A. Sabol of PP&L in a telephone conversation on August 5, 1981. During that conversation, Mr. Narrow was advised that the condition was considered potentially reportable under 10 CFR 50.55(e). The attachment to this letter contains a description of the problem, its cause, safety implications and the corrective action planned and underway. Since the details of this report provide information relevant to the reporting requirements of 10 CFR 21, this correspondence is considered to also discharge any formal responsibility PP&L may have in compliance thereto. We expect to issue a final report on the problem in November, 1981. We expect the Commission will find this information to be satisfactory. Very truly yours, L N. W. Curtis Vice President-Engineering C Construction-Nuclear FLW sab Attachment [#[f '8109290275 810922 PDR ADOCK 05000387 f S PDR
Mr. R. C. Haynes September 22, 1981 cc: Mr. Victor Stello (15) Director-Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. G. Mcdonald, Director (1) Office of Management Information & Program Control U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. Gary Rhoads U. S. Nuclear Regulatory Commission P.O. Box 52 Shickshinny, PA 18655 1 1
ATTACHMENT TO PLA-930 Subject Agastat GP Series Relay Bases Description of Potential Problem The Agastat GP relay is a general purp'se, auxiliary relay, which is used as a contact multiplier. These relays are used in various safety-related systems at Susquehanna. A problem has been identified with the electrical wire terminations to the relay base. Several relays have been found with terminal screws and/or terminal nuts (referred to as locking springs by Agastat) having stripped threads. To date, this problem has been identified only in panels supplied by Comsip Custom Line. Cause The term.nal nut is a thin nut approximately 1/16 in. thick with few screw threads. The nut floats freely, parallel to the direction of travel of the terminal screw. The nut is prevented from rotating by the molded relay base. Bacause of the nature of the free floating nut, it is possible t; cross thread the screw into the nut, thereby stripping the nut. Also, due to the thinness of the nut, overtightening of the screw can also result in stripping the nut. There are no torquing requirements specified by the manufacturer. When the terminal threads are stripped, the electrical integrity of the wire terminations
- is questionable.
Safety Implications Project Engineering does not have conclusive evidence as to the cause and nature of the stripped terminal screws. Also, the extent of this problem, which poses the potentiel for causing Class lE circuit failures, is unknown. How6ver due to the potential for this defect cccurring in Class 1E circuits, it has been determined that this condition is potentially reportable as a significant deficiency under the requirements of 10 CFB 50.55(e). Corrective Action An inspection of the electrical terminations on the Agastat GP series relay bases in the panels supplied by Comsip will be initiated by Bechtel to determine the extent of the stripping problem. The cause and nature of the inadequate terminations will then be reviewed with Comsip and additional action planned accordingly. Meanwhile, the current corrective action by the Integrated Startup Group is to replace all Agastat GP series relay bases in the panels supplied by Comsip with a different design relay base. The final report on this deficiency is expected to be issued in November, 1981. Bechtel & PP&L NCR's #7492 and 81-392 respectively identify the condition and will control cerrection. Page 1 of 1 .}}