ML20046C659
| ML20046C659 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 08/05/1993 |
| From: | Hagan J Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-PT21-93 NLR-N93131, NUDOCS 9308110315 | |
| Download: ML20046C659 (6) | |
Text
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~i Pubhc Sennce E4ctre ard Gu Company Joseph J. Hagan Public Service Electric and Gas Company P.O. E,ox 236. Hancocks Bridge, NJ 08038 609-339-1200 Vice Pres oent - Noctem Opwsons NLR-N93131 x United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:
1 10CFR21 NOTIFICATION COMSIP MICROSWITCHES HOPE CREEK GENERATING STATION DOCKET NO. 50-354 Pursuant to the notification requirements of 10CFR21, Public j
Service Electric and Gas (PSE&G) hereby provides the at* ched report concerning a deficiency in the qualified life calculation for microswitches manufactured by COMSIP.
This deficiency was reported to the NRC Operations Center on July 7, 1993. fully describes the identified deficiency and corrective actions implemented.
Please do not hesitate to contact us if there are any questions regarding this submittal.
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Sincerely Attachments (3) i i
i 100036 i
9308110315 930005 M
I PDR ADOCK 05000354 M
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. AUG 0 51993 Document Control' Desk
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.NLR-N93131 C
U.
S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 i
Mr.
S.
Dembek, Licensing Project Manager - Hope Creek y
U.
S.
Nuclear Regulatory Commission.
I One White Flint North l
11555 Rockville Pike Rockville, MD 20852
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Mr. T. P. Johnson (SO9) i USNRC Senior Resident Inspector s
Mr.
K.
Tosch, Manager, IV NJ Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625 I
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ATTACHMENT 1 Backaround On April 29, 1993, a deficiency was identified regarding heat damage to COMSIP Series PTW-5300 DC powered microswitches installed at Hope Creek.
Subsequent walkdowns identified l
degradation of these microswitches in a total of 16 safety related and 14 non-safety related control panels located l
throughout the plant.
The list of panels that were identified r
with degraded switches is provided as Attachment 2.
l The function of the microswitch is to monitor the associated component's circuit integrity and is considered a non-safety function.
The failure mode of the microswitch that can affect l
I the safety function of the associated circuit is a short to ground.
During a postulated design basis accident, the microswitches will be exposed to 100% humidity for 30 minutes, which may cause the potential for a short.
This short may blow the main fuse, resulting in a loss of the associated circuit.
Evaluation PSE&G has reviewed the switch design.
During this review, a damaged switch was cut open to determine the switch's construction and its capability to withstand the expected temperatures.
It was determined that the cover of the switch is for mechanical protection only.
All of the switch internals were covered by epoxy except for the lead wires, which showed no signs of degradation or hardening.
Therefore, it was determined that the most critical component of the switch is the epoxy.
The switches were damaged by overheating; therefore, the l
temperature was measured in order to determine the extent of the overheating.
The switch cover temperature was 185'F when room temperature was 71*F.
The higher temperature at the switch cover was attributed to internal heat rise due to the resistor.
The evaluation also discovered that internal heat rise was not considered in the vendor's qualified life calculation, which I
PSE&G considers to be the root cause of this deficiency.
The microswitches were purchased with a 40 year. qualification.
A material evaluation of the epoxy subjected to the internal heat rise indicates that they will perform their function in a harsh environment for at least 7.7 years and for 9.2 years in a mild j
environment.
The 7.7 year life expectancy will expire on 12/30/93.
Therefore, there is no immediate safety significance at Hope Creek.
(When the initial notification of this deficiency was made, it was reported that the life expectancy would expire on 11/15/93.
The 11/15/93 date was the result of an arithmetical error.)
Page 1 of 2
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ATTACHMENT 1 (cont'd)
Corrective Actions The safety-related DC microswitches will be replaced prior to 12/30/93.
An evaluation was initiated concerning PTW-5200 Series AC microswitches because they were qualified by the same report as the PTW-5300 Series DC microswitches.
During the evaluation,_it was determined that the internal heat rise for the AC microswitches is 37*F, which is less than the internal heat rise for the DC microswitches.
Therefore, the AC microswitches have a longer life expectancy than the DC microswitches.
Qualification testing of PTW-5200 Series AC microswitches is on-going to determine a more precise qualified life, taking into account the internal heat rise.
The list of safety related panels that contain PTW-5200 Series AC microswitches is provided as.
PSE&G has notified the manufacturer of this deficiency.
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Page 2 of 2 i
'r ATTACHMENT 2 PANELS WITH DEGRADED 5300 SWITCHES
- (NON-SAFETY RELATED)
PANEL DESCRIPTION 1.
00-C-113 CONDENSATE REFUEL WATER STORAGE & TRANSFER PANEL l
2.
10-C-152 CHILLED WATER SYSTEM REMOTE PANEL 3.
10-C-183 TURBINE BUILDING HVAC PANEL l
4.
10-C-184 TURBINE BUILDING MG' SET VENT PANEL i
5.
10-C-187 TURBINE BUILDING UNIT COOLERS & BATTERY ROOM PANEL
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6.
10-C-202 RACS REMOTE PANEL 7.
00-C-320 GASEOUS RECOMBINER PANEL 8.
10-C-382 REACTOR & AUXILIARY BUILDING HVAC PANEL 9.
00-C-385 RADWASTE TANK VENT PANEL 10.
00-C-391 TSC - REMOTE SHUTDOWN PANEL
)
i 11.
1E-C-486 CLASS 1E PANEL ROOM HVAC PANEL l
12.
10-C-520 CIRC WATER REMOTE PANEL 13. -
00-C-590 CIRC WATER PUMP HOUSE HVAC PANEL 14.
00-C-591 AUX BOILER BUILDING HVAC PANEL 1 of.2 i
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1 ATTACHMENT 2 (cont'd)
PANELS WITH DEGRADED 5300 SWITCHES (SAFETY RELATED) i PANEL DESCRIPTION 1.
1A-C-201 SACS CONTROL PANEL 2.
1B-C-201 SACS CONTROL PANEL i
t 3.
1C-C-201 SACS CONTROL PANEL 4.
1D-C-201 SACS CONTROL PANEL 5.
11.-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL i
6.
1B-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL 7.
1C-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL 8.
1D-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL 9.
1A-C-483 DIESEL AREA HVAC PANEL 10.
1B-C-483 DIESEL AREA HVAC PANEL 11.
1C-C-483 DIESEL AREA HVAC PANEL 12.
1D-C-483 DIESEL AREA HVAC PANEL 13.
1A-C-535 SERVICE WATER PUMP PANEL
'5 14.
1B-C-516 SERVICE WATER PUMP PANEL 15.
1C-C-516 SERVICE WATER PUMP PANEL
-l 16.
1D-C-516 SERVICE WATER PUMP PANEL 2 of 2
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i ATTACHMENT 3 PANELS WITH 5200 SWITCHES (SAFETY RELATED)
~
t PANEL DESCRIPTION 1.
1A-C-201 SACS CONTROL PANEL.
2.
1B-C-201 SACS CONTROL PANEL 3.
1C-C-201 SACS CONTROL PANEL 4.
1D-C-201 SACS CONTROL PANEL 5.
1A-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL 6,
1B-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL 7.
1C-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL 8.
1D-C-281 REACTOR BUILDING UNIT COOLER CONTROL PANEL
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