ML20084E432
| ML20084E432 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/07/1974 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 324, 7-75, AO-50-237-74-81, NUDOCS 8304150067 | |
| Download: ML20084E432 (3) | |
Text
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,Commonwaalth Edison 3
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One Firp,onal_ Plaza. Chicago, Ilknois
\\\\ x G AddresQly to: Post Office Box 767 "V
Chicago, lilinois 60630 1
6 BBS Ltr. #7-75 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 January 7, 1974 Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations-Region III U. S. Atomic Energy Cor=ission 799 Roosevelt Road j
Glen Ellyn, Illinois 60137
SUBJECT:
REPORT OF AENORMAL OCCURRE!CE FER SETION 6.6.A 0F THE TEHNICAL SPECIFICATIO:?S SUSPECIED FAILURE OF LPCI SELECT CIRCUIT LOGIC RELAY
References:
- 1) Regulatory Cuide 1.16 Rev. 1, Appendix A
- 2) Notification of Region III of AEC Regulatory Operations Telephone:
Mr. P. Johncon, 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br /> on December 28, 1974 j
Telegrz.m:
Mr. J. Keppler, 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on Decemoer 30, 1974
- 3) Drawing Number:
12E2438A Report Number:' 50-237/74-81 j
Report Date: January 7, 1975 Occurrence Date: December 28, 1974 Pacility: Dresden Nuclear Fower Station, Morris, Illinois-g
_INDENTIFICATION OF OCCURRDICE On December 28,1974 at 1700 hours0.0197 days <br />0.472 hours <br />0.00281 weeks <br />6.4685e-4 months <br /> jumpers were being installed around differential pressure owitches DPIS 261-34A,-34B,-340, and -34D.
After the completion of the jumper installation it was noted that associated relay A.S. 284 had not encrgized as required.
Initially it was felt that the problem was equipment
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failure which would have had a direct affect on the LPCI logic cystem. Subsequent-investigation revealed that there had been no equilnent failure and thic i
i portion of LPCI logic had at all times been capable of preforming its designed function. Therefore, the event was not an abnormal occurrence.
CONDITIONS PRIOR TO OCCURRD;CE Prior to the occurrence, the plant was in the " Shutdown" mode. The unit is in a major refueling outage. Preparations are being made to perfom repairs on the 4
3 211 J,U; o 1975 8304150067 740107 i
PDR ADOCK 05000237 S
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(m Mr. Ja'meF3. Kep"? ')
January 7, 1974 t
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G "B" recire loop discharge valve bypass line.
DESCRIPTION OF OCCURRE!!CE Repairs were to be conducted to the "B" recire line and the associated jet pumps were to be plugged. However, the "B" loop is the preferred loop for LPCI injection. This necessitated the installation of jumpers such that LPCI, if required, would inject into the "A" loop.
Jumpers were placed around switches DPIS 261-34A, B, C, and D such that relays 183, 184, EG3, and 284 uould energize. The switches close when pressure in the "A" recire loop is one (1) poi hicher than precsure in the "B" recire loop.
The relays then energize and allow LPCI to inject into the "A" recire loop.
After positioning the jumpers, the procedure called for verification of relay pickup. At this time, it was observed that relay 1530-284 (AS) had not picked up.
This fact plus the evidence of carbon and oxidation around the relay led personnel to believe the relay had burned up.
DESIGIU.TlON OF APPARENT CAUSE OF OCCURRE!!CE As soon as the above stated conditions were observed, a work request was issued to conduct repairs. Electrical maintenance personnel removed the old relay and installed a new one.
The it.stallation of the new relay nocenM t.atod testire tn inmare proper operability.
It was discovered that the real reason for the old relay not actuating was due to improper installation of the jumper.
The carbon and oxidation found on the relay was due to the numerous actuations of the relay because of fluctuations in pressure between the two recire loops.
/MALYSIS OF OCCURRENCE This event in no way jeopardized the health and safety of the plant personnel or the general public. Had the misplacement of the jumper gono unnoticed, the "A" loop would still have been selected for LPCI injection. Similarly if relay 1530-284 (13) would have actually failed, LFCI logic could still have selected "A" loop for injection.
t CORPJITIVE ACTION Corrective action consisted of replacing the suspected failed relay with a like-for-31ke replacement. The old relay was taken back to the shop, bench tested satisfactorily, and cleaned up.
l Also, the jumper was removed, inspected, and reinstalled properly.
1
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. Mr. Jamw-6. Kep *' r -
\\V; January 7, 1975 QJ FAILURE DATA Althouc,h the relay was ultimately found not to be failed, relay 1530-284 (AS) was a General Electric auxiliary relay, model number 12HGA11J52, type HGA.
Sincerely,
,p wm
-(V Yu M
'63. B. Stephencon Superintendent BBS:HJHrsmp Dresden Nuclear Power Station File /AEC Corr.
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