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{{#Wiki_filter:Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Je.rsey 08038 Salem Generating Station | {{#Wiki_filter:Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Je.rsey 08038 Salem Generating Station August 15, 1991 | ||
* U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 | * U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 | ||
==Dear Sir:== | ==Dear Sir:== | ||
SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO.. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 91-010-00 | |||
* | SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO.. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 91-010-00 This Licensee Event Report is being submitted pursuant to the requirements of the Code of Federal Regulations lOCFR so;73(a) (2) (iv). This report is required within thirty (30) days of discovery. | ||
... | * Sincerely yours, 1/CJ-V4r;, | ||
SEQUENTIAL)'::::::::. | C. A. Vondra tr7G-'(./ | ||
REVISION MONTH ::::::::'.: | General Manager - | ||
NUMBER NUMBER | Salem Operations MJP:pc Distribution | ||
( | ...: 1 i e En er o *. * :- !_*, *. .} ;~; t c 91002b6Q?~ 910815 PDR ADOCK 05000311 95-2189 (10MJ 12-89 c PDR | ||
- | |||
)(ii | NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED OMS NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LERI COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. | ||
-- | FACILITY NAME (1) DOCKET NUMBER (21 I PAGE 131 Salem Generating Station - Unit 2 o I 5 I o I o I o I 31 1 11 I 1 OF n I ') | ||
TITLE (4) 2 ESF Actuation Signals: Cont. Vent. Isol. & Auto Switch *6f Control Rm Vent. | |||
)(iii I 60,73(1)(2)(;) | ' | ||
60.73(1) (2i(viii) (Al | EVENT DATE (5) LER NUMBER (61 REPORT DATE (7) OTHER FACILITIES INVOLVED (81 MONTH DAY YEAR YEAR :::::::::: SEQUENTIAL)'::::::::. REVISION MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER(SI | ||
::::::::'.: NUMBER ~'.:'.:'.:'.::* NUMBER q7 213 9 1 9 I 1 - o11 10 - o 10 o 1s 115 9 I 1 01s1010101 I I THIS REPORT IS SUBMITTED PURSUANT TO THE R~OUIREMENTS OF 10 CFR §:(Check one or more of the following} (111 OPERATING 1 | |||
)(vi 60.73(o)(2)(iii) 50.73(o)(2i(x) | -x MODE (9) 20.402(bl 20.405(c) 50,73(o)(2)(iv) 73.71(bl POWER LEVEL I 11 0 I 0 | ||
LICENSEE CONTACT FOR THIS LEA (121 NAME AREA CODE M. J. Pollack -LER Coordinator | - 20.406(*)(1 )(ii 20.405(oi(1)(ii) | ||
....... *.*.-.* | - | ||
:.:. * | - | ||
60.36(c)(1 I 50.36(cl(21 | |||
.. .. . | - | ||
I I I I I I I , ... ........ .... ;:* ;*.-;*.-*:*:-:-:-:-:* | 50.73(ol(2)(v) 60.73(ol(2)(vii) | ||
1:.--:-:-:-:-... .*.*.*.* .*.*.*.-*:*:*:-:-:-:-: | - | ||
- | |||
:*:*:-:-:;:*:*:;:.:-:*:*:*:*: | 73.71(cl OTHER (Spacify in Abstract 1101 | ||
,:,:.:-:-:-:-:-:-:-:- | - - - below snd in Text, NRC Form l~"ll!lfJ!!l!l~I= | ||
::::::::::::::::::::::::::::: | 20,406(a)(1 )(iii I 60,73(1)(2)(;) 60.73(1) (2i(viii) (Al 366AI 20 ..W6(11(1) (Iv) | ||
I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR n YES (If yes, complete EXPECTED SUBMISSION DATE} | - 60.73(o)(2i(ii) | ||
DATE (151 I I This Licensee Event Report addresses two (2) Engineered Safety Feature (ESF) signals initiated through the Radiation Monitoring System (RMS}. One ESV signal was for the automatic switching of the Control Room ventilation from normal to the emergency mode of operation (100% recirculation} | *- 50.73(11(2i(vlli)(BI 20.406(*1(1 )(vi | ||
and the other for a Containment Purge/Pressure-Vacuum Relief (CP/P-VR) | -* 60.73(o)(2)(iii) | ||
System isolation. | - 50.73(o)(2i(x) | ||
Both events occurred on July 23, 1991. The cause of the Control Room Ventilation switch was a high channel spike on the 2R1B RMS channel (Control Room Ventilation Intake Duct monitor). | LICENSEE CONTACT FOR THIS LEA (121 NAME TELEPHONE NUMBER AREA CODE M. J. Pollack - LER Coordinator COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 | ||
The cause of the Containment Ventilation Isolation signal was a high channel spike on the 2R45C (Plant Vent High Range Noble Gas monitor) channel which caused the Plant Vent Noble Gas RMS channels (2R41C respectively) to de-energize. | .......*.*.-.* :-::-:-:-:* | ||
The root cause of the 2R1B channel spike is equipment design. The 2R1B RMS channel monitor is a Victoreen 843-22, Beta Scintillator. | ,...... :.*. | ||
Periodic problems with the Victoreen system have been experienced, as indicated in prior LERs (e.g., 311/90-040-00). | CAUSE SYSTEM COMPONENT MANUFAC* REPORTABLE ,... -.*;* *.*. .*.* CAUSE SYSTEM COMPONENT MANUFAC* | ||
Also, the Salem Unit 2 RMS is susceptible to voltage transients. | TUR ER TO NPRDS t.;.*.*.* :.:. <**;*;*.-; .... TUR ER | ||
Investigation of the 2RlB channel CP/P-VRS isolation signal did not identify any failed components. | *:-:-:*:* .. .. .,.,. .;.;. | ||
The root cause of the 2R45C channel spike is equipment failure. A resistor in the detector assembly was found to have one of its connections broken. The assembly was subsequently replaced. | :*:* .,. *.:..;.:*.-. | ||
NRC Form 366 (6-891 | :.; .. :.: *.*. | ||
Westinghouse | .*.* .... ::*: :*:**:* ;*c 1.*.: -:*:*:* *.*. :::::::::::: I I I I I I I I I I I I I I | ||
-Pressurized Water Reactor | ,... ........ .... ;:* ;*.-;*.- *:*:-:-:-:-:* | ||
2 Engineered Safety Feature signals initiated from the Radiation Monitoring System Event Date: 7/23/91 Report Date: 8/15/91 This report was initiated by Incident Report *Nos. 91-502 and 91-503. CONDITIONS PRIOR TO OCCURRENCE: | 1:.- -:-:-:-:- ... .*.*.*.* .*.*.*.-*:*:*:-:-:-:-: | ||
Mode 1 Reactor Power 100% -Unit Load 1120 MWe DESCRIPTION OF OCCURRENCE: | .*.* :-:-:-:*:*:*: :*:*:-:-:;:*:*:;:.:-:*:*:*:*: | ||
This Licensee Event Report addresses two (2) Engineered Safety Feature (ESF) signals initiated through the Radiation Monitoring System (RMS) {ILi. One ESF signal was for the automatic* | I I I I I I I ,:,:.:-:-:-:-:-:-:-:- ::::::::::::::::::::::::::::: I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED n YES (If yes, complete EXPECTED SUBMISSION DATE} | ||
switching of the Control Room ventilation | ABSTRACT (Limit to 1400 spsctJs, i.e., approximately fifteen single-space typewritten Unes} 116) bl NO SUBMISSION* | ||
{VII from normal to the emergency mode of operation (100% recirculation) and the other for a Containment Purge/Pressure-Vacuum Relief (CP/P-VR) | DATE (151 I I I This Licensee Event Report addresses two (2) Engineered Safety Feature (ESF) signals initiated through the Radiation Monitoring System (RMS}. One ESV signal was for the automatic switching of the Control Room ventilation from normal to the emergency mode of operation (100% | ||
System {BF) isolation. | recirculation} and the other for a Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System isolation. Both events occurred on July 23, 1991. The cause of the Control Room Ventilation switch was a high channel spike on the 2R1B RMS channel (Control Room Ventilation Intake Duct monitor). The cause of the Containment Ventilation Isolation signal was a high channel spike on the 2R45C (Plant Vent High Range Noble Gas monitor) channel which caused the Plant Vent Noble Gas RMS channels (2R41C respectively) to de-energize. The root cause of the 2R1B channel spike is equipment design. The 2R1B RMS channel monitor is a Victoreen 843-22, Beta Scintillator. Periodic problems with the Victoreen system have been experienced, as indicated in prior LERs (e.g., 311/90-040-00). Also, the Salem Unit 2 RMS is susceptible to voltage transients. Investigation of the 2RlB channel CP/P-VRS isolation signal did not identify any failed components. The root cause of the 2R45C channel spike is equipment failure. A resistor in the detector assembly was found to have one of its connections broken. The assembly was subsequently replaced. | ||
Both events occurred on July 23, 1991. On Jtily 23, 1991, at 1236 hours, the Control Room Ventilation Intake Duct RMS channel (2R1B) spiked high. This resulted in Control Room ventilation switching to the emergency mode of operation for both Salem Units (by design). On July 23, 1991 at 1732 hours, the high range Plant Vent noble gas radiaiion monitor (2R45C) channel spiked high. This caused the Plant Vent Noble Gas RMS channel (2R41C) to de-energize resulting in a CP/P-VR System isolation signal (by design). Technical Specification 3.3.3.1 Action b26 (for 2R45C channel inoperability) was entered at the time of the event. It states: "With the number of OPERABLE Channels less than required by the Minimum Channels OPERABLE requirements, initiate the preplanned alternate method of monitoring the appropriate parameter(s), within 72 hours, and: 1) either restore the inoperable Channel(s) to OPERABLE status within 7 days of the event, or 2) prepare and submit a Special Report to the Commission LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station | NRC Form 366 (6-891 | ||
DOCKET NUMBER | |||
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION . | |||
Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311. 91-010-00 2 of 5 PLANT AND SYSTEM IDENTIFICATION: | |||
Westinghouse - Pressurized Water Reactor Energy Industry Identification System (EIIS) codes are identified in the* text as {xx) | |||
IDENTIFICATION OF OCCURRENCE: | |||
2 Engineered Safety Feature signals initiated from the Radiation Monitoring System Event Date: 7/23/91 Report Date: 8/15/91 This report was initiated by Incident Report *Nos. 91-502 and 91-503. | |||
CONDITIONS PRIOR TO OCCURRENCE: | |||
Mode 1 Reactor Power 100% - Unit Load 1120 MWe DESCRIPTION OF OCCURRENCE: | |||
This Licensee Event Report addresses two (2) Engineered Safety Feature (ESF) signals initiated through the Radiation Monitoring System (RMS) | |||
{ILi. One ESF signal was for the automatic* switching of the Control Room ventilation {VII from normal to the emergency mode of operation (100% recirculation) and the other for a Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System {BF) isolation. Both events occurred on July 23, 1991. | |||
On Jtily 23, 1991, at 1236 hours, the Control Room Ventilation Intake Duct RMS channel (2R1B) spiked high. This resulted in Control Room ventilation switching to the emergency mode of operation for both Salem Units (by design). | |||
On July 23, 1991 at 1732 hours, the high range Plant Vent noble gas radiaiion monitor (2R45C) channel spiked high. This caused the Plant Vent Noble Gas RMS channel (2R41C) to de-energize resulting in a CP/P-VR System isolation signal (by design). Technical Specification 3.3.3.1 Action b26 (for 2R45C channel inoperability) was entered at the time of the event. It states: | |||
"With the number of OPERABLE Channels less than required by the Minimum Channels OPERABLE requirements, initiate the preplanned alternate method of monitoring the appropriate parameter(s), | |||
within 72 hours, and: | |||
: 1) either restore the inoperable Channel(s) to OPERABLE status within 7 days of the event, or | |||
: 2) prepare and submit a Special Report to the Commission | |||
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 91-010-00 3 of 5 DESCRIPTION OF OCCURRENCE: (cont'd) pursuant to Specification 6.9.2 within 14 days following the event outlining the action taken, the cause of the inoperability and the plans and sch~duled fo~ restoring the system to OPERABLE status." | |||
The Nuclear Regulatory Commission (NRC) was notified of each ESF actuat_ion in accordance with Code of Federal Regulations lOCFR 50.72(b) (2) (ii) on July 23, 1991 at 1320 hours and 1932 hours, respectively. | |||
APPARENT CAUSE OF OCCURRENCE: | APPARENT CAUSE OF OCCURRENCE: | ||
The root cause of the 2RlB channel spike is equipment design. The type of detector system used for the majority of the Salem Unit 2 RMS channels is manufactured by Victoreen. | The root cause of the 2RlB channel spike is equipment design. The type of detector system used for the majority of the Salem Unit 2 RMS channels is manufactured by Victoreen. The 2R1B RMS channel monitor is a Victoreen 843-22, Beta Scintillator. Periodic problems with the Victoreen system have been experienced, as indicated in prior LERs (e.g., 311/90-04"0-00). Aiso, the Salem Unit 2 RMS is susceptible to voltage transients. | ||
The 2R1B RMS channel monitor is a Victoreen 843-22, Beta Scintillator. | Investigation of the 2R1B channel CP/P-VRS isolation signal did not identify any failed components. Detailed visual inspections were conducted. No *concerns.were noted (e.g., backplane pins appeared int~ct and detector connections were intact). A channel calibration was performed and successfully completed. | ||
Periodic problems with the Victoreen system have been experienced, as indicated in prior LERs (e.g., 311/90-04"0-00). | The root cause of the 2R45C channel spike is equipment failure. A resistor i'n the detector assembly was found to have one of its connections broken. | ||
Aiso, the Salem Unit 2 RMS is susceptible to voltage transients. | 2R1B - ANALYSIS OF OCCURRENCE: | ||
Investigation of the 2R1B channel CP/P-VRS isolation signal did not identify any failed components. | The 2R1B channel continuously monitors air from the HVAC intake duct into the Unit 2 Control Room. This monitor consists of four parallel Geiger-Mueller (GM) tubes. When any of the four GM tubes reaches the alarm setpoint the monitor actuates an alarm and initiates closure of the duct intake valve to prevent contaminated air from entering the Control Room. | ||
Detailed visual inspections were conducted. | During the time the 2R1B channel was inoperable, the 2R1A Control Room General Area Monitor RMS channel remained operable. It did not indicate any significant increase in radiation levels. The 2RlA RMS channel also has the same automatic ESF function for Control Room ventilation isolation. | ||
No *concerns.were noted (e.g., backplane pins appeared and detector connections were intact). A channel calibration was performed and successfully completed. | Upon receipt of the 2R1B .high channel spike, a Control Room air sample was initiated by Radiation Protection. No significant increase in airborne activity was identified. | ||
The root cause of the 2R45C channel spike is equipment failure. A resistor i'n the detector assembly was found to have one of its connections broken. 2R1B -ANALYSIS OF OCCURRENCE: | As indicated previously, ~he automatic switching of the Control Room ventilation system to the accident mode of operation, was not caused | ||
The 2R1B channel continuously monitors air from the HVAC intake duct into the Unit 2 Control Room. This monitor consists of four parallel Geiger-Mueller (GM) tubes. When any of the four GM tubes reaches the alarm setpoint the monitor actuates an alarm and initiates closure of the duct intake valve to prevent contaminated air from entering the Control Room. During the time the 2R1B channel was inoperable, the 2R1A Control Room General Area Monitor RMS channel remained operable. | |||
It did not indicate any significant increase in radiation levels. The 2RlA RMS channel also has the same automatic ESF function for Control Room ventilation isolation. | LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 91-010-00 4 of 5 2R1B - ANALYSIS OF OCCURRENCE: (cont'd) by an actual high radiation signal~ *Therefore, the health and safety of the public was not affected by this event. However, since the switching to the accident mode of operation by the control room ventilation system is an ESF actuation, this event is reportable in accordance with the Code of Federal Regulations lOCFR | ||
Upon receipt of the 2R1B .high channel spike, a Control Room air sample was initiated by Radiation Protection. | : 50. 7 3 (a) ( 2) (iv) | ||
No significant increase in airborne activity was identified. | * 2R45C - ANALYSIS OF OCCURRENCE: | ||
As indicated previously, automatic switching of the Control Room ventilation system to the accident mode of operation, was not caused LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 2R1B -ANALYSIS OF OCCURRENCE: | Isolation of the CP/P-VRS is part of the design Engineered Safety Features (ESFs) . I~ mitigates the release of excessive quantities of radioactive material to the environment after a design base accident. | ||
The 2R45C channel is interlocked with the 2R41 detectors and sample pump to cause them to de-energize upon reaching the high radiation level setpoint. This is de~igned to protect the 2R41 channel detectors. When the 2R41C detector is de-energized, an ESF CP/P-VRS isolation signal is generated, as per conservative design. | |||
*Therefore, the health and safety of the public was not affected by this event. However, since the switching to the accident mode of operation by the control room ventilation system is an ESF actuation, this event is reportable in accordance with the Code of Federal Regulations lOCFR 50. 7 3 (a) ( 2) (iv) | The 2R41C channel monitors plant vent effluent releases for radioactive noble gas via representative sampling. The ESF actuation feature of CP/P-VRS isolation, associated with this channel, is of conservative design. It is redundant to the 2R12A channel. In addition to its ESF function, the channel closes the 2WG41 valve (Waste Gas Decay Tank Vent Control Valve). | ||
* 2R45C -ANALYSIS OF OCCURRENCE: | At the time of this event, neither Containment Purge, Containment Pressure/Vacuum Relief nor Waste Gas Decay Tank release was in progress. The valves associated with these functions were already in the closed position. | ||
Isolation of the CP/P-VRS is part of the design Engineered Safety Features (ESFs) . mitigates the release of excessive quantities of radioactive material to the environment after a design base accident. | The 2R45C channel detector is an Eberline SA-15 energy compensated GM tube. | ||
The 2R45C channel is interlocked with the 2R41 detectors and sample pump to cause them to de-energize upon reaching the high radiation level setpoint. | The inadvertent CP/P-VRS isolation signal was caused by an equipment failure, not the result of high activity. Therefore, this event did not affect the health or safety of the public. However, due to the actuation of an ESF function, this event is reportable in accordance with Code of Federal Regulations lOCFR 50.73(a) (2) (iv). | ||
This is to protect the 2R41 channel detectors. | CORRECTIVE ACTION: | ||
When the 2R41C detector is de-energized, an ESF CP/P-VRS isolation signal is generated, as per conservative design. The 2R41C channel monitors plant vent effluent releases for radioactive noble gas via representative sampling. | As identified in the Apparent Cause of Occurrence section, the investigation of the 2R1B channel CP/P-VRS isolation signal did not identify any failed components. Detailed visual inspections were conducted and a channel calibration was performed and successfully completed. On July 24, 1991, the channel was returned to service. | ||
The ESF actuation feature of CP/P-VRS isolation, associated with this channel, is of conservative design. It is redundant to the 2R12A channel. In addition to its ESF function, the channel closes the 2WG41 valve (Waste Gas Decay Tank Vent Control Valve). At the time of this event, neither Containment Purge, Containment Pressure/Vacuum Relief nor Waste Gas Decay Tank release was in progress. | After a 24 hour observation period, the channel was declared operable. | ||
The valves associated with these functions were already in the closed position. | Periodic problems with Victoreen RMS equipment have been experienced, as indicated in prior LERs (e.g., 311/90-044-00). Due to those other | ||
The 2R45C channel detector is an Eberline SA-15 energy compensated GM tube. The inadvertent CP/P-VRS isolation signal was caused by an equipment failure, not the result of high activity. | |||
Therefore, this event did not affect the health or safety of the public. However, due to the actuation of an ESF function, this event is reportable in accordance with Code of Federal Regulations lOCFR 50.73(a) (2) (iv). CORRECTIVE ACTION: As identified in the Apparent Cause of Occurrence section, the investigation of the 2R1B channel CP/P-VRS isolation signal did not identify any failed components. | LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating.Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 91-010-00 5 of 5 r | ||
Detailed visual inspections were conducted and a channel calibration was performed and successfully completed. | CORRECTIVE ACTION: (cont'd) events, sever~l syste~ design modifications are being considered to eliminate the spurious ESF actuation signals. These design modifications include a proposal for RMS channel equivalent replacement. | ||
On July 24, 1991, the channel was returned to service. After a 24 hour observation period, the channel was declared operable. | The 2R45C detector assembly was replaced. The channel was declared operable and Technical ~pecification 3.3.3.1 Action b26 was exited on July 26, 199i at 0430 hours upon successful completion of a cha~nel functional test. | ||
Periodic problems with Victoreen RMS equipment have been experienced, as indicated in prior LERs (e.g., 311/90-044-00). | /' | ||
Due to those other LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating.Station | _~!/ | ||
The 2R45C detector assembly was replaced. | /;rt?~-,. | ||
The channel was declared operable and Technical 3.3.3.1 Action b26 was exited on July 26, 199i at 0430 hours upon successful completion of a functional test. | ( 7r - | ||
-( 7r General Manager &°'--" | General Manager Salem Operations | ||
&°'--" | |||
MJP:pc SORC Mtg.. 91-084}} |
Revision as of 11:31, 21 October 2019
ML18096A218 | |
Person / Time | |
---|---|
Site: | Salem ![]() |
Issue date: | 08/15/1991 |
From: | Pollack M, Vondra C Public Service Enterprise Group |
To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
References | |
LER-91-010-02, LER-91-10-2, NUDOCS 9108260024 | |
Download: ML18096A218 (6) | |
Text
Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Je.rsey 08038 Salem Generating Station August 15, 1991
- U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Dear Sir:
SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO.. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 91-010-00 This Licensee Event Report is being submitted pursuant to the requirements of the Code of Federal Regulations lOCFR so;73(a) (2) (iv). This report is required within thirty (30) days of discovery.
- Sincerely yours, 1/CJ-V4r;,
C. A. Vondra tr7G-'(./
General Manager -
Salem Operations MJP:pc Distribution
...: 1 i e En er o *. * :- !_*, *. .} ;~; t c 91002b6Q?~ 910815 PDR ADOCK 05000311 95-2189 (10MJ 12-89 c PDR
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED OMS NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LERI COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.
FACILITY NAME (1) DOCKET NUMBER (21 I PAGE 131 Salem Generating Station - Unit 2 o I 5 I o I o I o I 31 1 11 I 1 OF n I ')
TITLE (4) 2 ESF Actuation Signals: Cont. Vent. Isol. & Auto Switch *6f Control Rm Vent.
'
EVENT DATE (5) LER NUMBER (61 REPORT DATE (7) OTHER FACILITIES INVOLVED (81 MONTH DAY YEAR YEAR :::::::::: SEQUENTIAL)'::::::::. REVISION MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER(SI
- '.: NUMBER ~'.:'.:'.:'.::* NUMBER q7 213 9 1 9 I 1 - o11 10 - o 10 o 1s 115 9 I 1 01s1010101 I I THIS REPORT IS SUBMITTED PURSUANT TO THE R~OUIREMENTS OF 10 CFR §:(Check one or more of the following} (111 OPERATING 1
-x MODE (9) 20.402(bl 20.405(c) 50,73(o)(2)(iv) 73.71(bl POWER LEVEL I 11 0 I 0
- 20.406(*)(1 )(ii 20.405(oi(1)(ii)
-
-
60.36(c)(1 I 50.36(cl(21
-
50.73(ol(2)(v) 60.73(ol(2)(vii)
-
-
73.71(cl OTHER (Spacify in Abstract 1101
- - - below snd in Text, NRC Form l~"ll!lfJ!!l!l~I=
20,406(a)(1 )(iii I 60,73(1)(2)(;) 60.73(1) (2i(viii) (Al 366AI 20 ..W6(11(1) (Iv)
- 60.73(o)(2i(ii)
- - 50.73(11(2i(vlli)(BI 20.406(*1(1 )(vi
-* 60.73(o)(2)(iii)
- 50.73(o)(2i(x)
LICENSEE CONTACT FOR THIS LEA (121 NAME TELEPHONE NUMBER AREA CODE M. J. Pollack - LER Coordinator COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131
.......*.*.-.* :-::-:-:-:*
,...... :.*.
CAUSE SYSTEM COMPONENT MANUFAC* REPORTABLE ,... -.*;* *.*. .*.* CAUSE SYSTEM COMPONENT MANUFAC*
TUR ER TO NPRDS t.;.*.*.* :.:. <**;*;*.-; .... TUR ER
- -:-:*:* .. .. .,.,. .;.;.
- .,. *.:..;.:*.-.
- .; .. :.: *.*.
.*.* .... ::*: :*:**:* ;*c 1.*.: -:*:*:* *.*. :::::::::::: I I I I I I I I I I I I I I
,... ........ .... ;:* ;*.-;*.- *:*:-:-:-:-:*
1:.- -:-:-:-:- ... .*.*.*.* .*.*.*.-*:*:*:-:-:-:-:
.*.* :-:-:-:*:*:*: :*:*:-:-:;:*:*:;:.:-:*:*:*:*:
I I I I I I I ,:,:.:-:-:-:-:-:-:-:- ::::::::::::::::::::::::::::: I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED n YES (If yes, complete EXPECTED SUBMISSION DATE}
ABSTRACT (Limit to 1400 spsctJs, i.e., approximately fifteen single-space typewritten Unes} 116) bl NO SUBMISSION*
DATE (151 I I I This Licensee Event Report addresses two (2) Engineered Safety Feature (ESF) signals initiated through the Radiation Monitoring System (RMS}. One ESV signal was for the automatic switching of the Control Room ventilation from normal to the emergency mode of operation (100%
recirculation} and the other for a Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System isolation. Both events occurred on July 23, 1991. The cause of the Control Room Ventilation switch was a high channel spike on the 2R1B RMS channel (Control Room Ventilation Intake Duct monitor). The cause of the Containment Ventilation Isolation signal was a high channel spike on the 2R45C (Plant Vent High Range Noble Gas monitor) channel which caused the Plant Vent Noble Gas RMS channels (2R41C respectively) to de-energize. The root cause of the 2R1B channel spike is equipment design. The 2R1B RMS channel monitor is a Victoreen 843-22, Beta Scintillator. Periodic problems with the Victoreen system have been experienced, as indicated in prior LERs (e.g., 311/90-040-00). Also, the Salem Unit 2 RMS is susceptible to voltage transients. Investigation of the 2RlB channel CP/P-VRS isolation signal did not identify any failed components. The root cause of the 2R45C channel spike is equipment failure. A resistor in the detector assembly was found to have one of its connections broken. The assembly was subsequently replaced.
NRC Form 366 (6-891
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION .
Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311. 91-010-00 2 of 5 PLANT AND SYSTEM IDENTIFICATION:
Westinghouse - Pressurized Water Reactor Energy Industry Identification System (EIIS) codes are identified in the* text as {xx)
IDENTIFICATION OF OCCURRENCE:
2 Engineered Safety Feature signals initiated from the Radiation Monitoring System Event Date: 7/23/91 Report Date: 8/15/91 This report was initiated by Incident Report *Nos.91-502 and 91-503.
CONDITIONS PRIOR TO OCCURRENCE:
Mode 1 Reactor Power 100% - Unit Load 1120 MWe DESCRIPTION OF OCCURRENCE:
This Licensee Event Report addresses two (2) Engineered Safety Feature (ESF) signals initiated through the Radiation Monitoring System (RMS)
{ILi. One ESF signal was for the automatic* switching of the Control Room ventilation {VII from normal to the emergency mode of operation (100% recirculation) and the other for a Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System {BF) isolation. Both events occurred on July 23, 1991.
On Jtily 23, 1991, at 1236 hours0.0143 days <br />0.343 hours <br />0.00204 weeks <br />4.70298e-4 months <br />, the Control Room Ventilation Intake Duct RMS channel (2R1B) spiked high. This resulted in Control Room ventilation switching to the emergency mode of operation for both Salem Units (by design).
On July 23, 1991 at 1732 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.59026e-4 months <br />, the high range Plant Vent noble gas radiaiion monitor (2R45C) channel spiked high. This caused the Plant Vent Noble Gas RMS channel (2R41C) to de-energize resulting in a CP/P-VR System isolation signal (by design). Technical Specification 3.3.3.1 Action b26 (for 2R45C channel inoperability) was entered at the time of the event. It states:
"With the number of OPERABLE Channels less than required by the Minimum Channels OPERABLE requirements, initiate the preplanned alternate method of monitoring the appropriate parameter(s),
within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, and:
- 1) either restore the inoperable Channel(s) to OPERABLE status within 7 days of the event, or
- 2) prepare and submit a Special Report to the Commission
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 91-010-00 3 of 5 DESCRIPTION OF OCCURRENCE: (cont'd) pursuant to Specification 6.9.2 within 14 days following the event outlining the action taken, the cause of the inoperability and the plans and sch~duled fo~ restoring the system to OPERABLE status."
The Nuclear Regulatory Commission (NRC) was notified of each ESF actuat_ion in accordance with Code of Federal Regulations lOCFR 50.72(b) (2) (ii) on July 23, 1991 at 1320 hours0.0153 days <br />0.367 hours <br />0.00218 weeks <br />5.0226e-4 months <br /> and 1932 hours0.0224 days <br />0.537 hours <br />0.00319 weeks <br />7.35126e-4 months <br />, respectively.
APPARENT CAUSE OF OCCURRENCE:
The root cause of the 2RlB channel spike is equipment design. The type of detector system used for the majority of the Salem Unit 2 RMS channels is manufactured by Victoreen. The 2R1B RMS channel monitor is a Victoreen 843-22, Beta Scintillator. Periodic problems with the Victoreen system have been experienced, as indicated in prior LERs (e.g., 311/90-04"0-00). Aiso, the Salem Unit 2 RMS is susceptible to voltage transients.
Investigation of the 2R1B channel CP/P-VRS isolation signal did not identify any failed components. Detailed visual inspections were conducted. No *concerns.were noted (e.g., backplane pins appeared int~ct and detector connections were intact). A channel calibration was performed and successfully completed.
The root cause of the 2R45C channel spike is equipment failure. A resistor i'n the detector assembly was found to have one of its connections broken.
2R1B - ANALYSIS OF OCCURRENCE:
The 2R1B channel continuously monitors air from the HVAC intake duct into the Unit 2 Control Room. This monitor consists of four parallel Geiger-Mueller (GM) tubes. When any of the four GM tubes reaches the alarm setpoint the monitor actuates an alarm and initiates closure of the duct intake valve to prevent contaminated air from entering the Control Room.
During the time the 2R1B channel was inoperable, the 2R1A Control Room General Area Monitor RMS channel remained operable. It did not indicate any significant increase in radiation levels. The 2RlA RMS channel also has the same automatic ESF function for Control Room ventilation isolation.
Upon receipt of the 2R1B .high channel spike, a Control Room air sample was initiated by Radiation Protection. No significant increase in airborne activity was identified.
As indicated previously, ~he automatic switching of the Control Room ventilation system to the accident mode of operation, was not caused
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 91-010-00 4 of 5 2R1B - ANALYSIS OF OCCURRENCE: (cont'd) by an actual high radiation signal~ *Therefore, the health and safety of the public was not affected by this event. However, since the switching to the accident mode of operation by the control room ventilation system is an ESF actuation, this event is reportable in accordance with the Code of Federal Regulations lOCFR
- 50. 7 3 (a) ( 2) (iv)
- 2R45C - ANALYSIS OF OCCURRENCE:
Isolation of the CP/P-VRS is part of the design Engineered Safety Features (ESFs) . I~ mitigates the release of excessive quantities of radioactive material to the environment after a design base accident.
The 2R45C channel is interlocked with the 2R41 detectors and sample pump to cause them to de-energize upon reaching the high radiation level setpoint. This is de~igned to protect the 2R41 channel detectors. When the 2R41C detector is de-energized, an ESF CP/P-VRS isolation signal is generated, as per conservative design.
The 2R41C channel monitors plant vent effluent releases for radioactive noble gas via representative sampling. The ESF actuation feature of CP/P-VRS isolation, associated with this channel, is of conservative design. It is redundant to the 2R12A channel. In addition to its ESF function, the channel closes the 2WG41 valve (Waste Gas Decay Tank Vent Control Valve).
At the time of this event, neither Containment Purge, Containment Pressure/Vacuum Relief nor Waste Gas Decay Tank release was in progress. The valves associated with these functions were already in the closed position.
The 2R45C channel detector is an Eberline SA-15 energy compensated GM tube.
The inadvertent CP/P-VRS isolation signal was caused by an equipment failure, not the result of high activity. Therefore, this event did not affect the health or safety of the public. However, due to the actuation of an ESF function, this event is reportable in accordance with Code of Federal Regulations lOCFR 50.73(a) (2) (iv).
CORRECTIVE ACTION:
As identified in the Apparent Cause of Occurrence section, the investigation of the 2R1B channel CP/P-VRS isolation signal did not identify any failed components. Detailed visual inspections were conducted and a channel calibration was performed and successfully completed. On July 24, 1991, the channel was returned to service.
After a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> observation period, the channel was declared operable.
Periodic problems with Victoreen RMS equipment have been experienced, as indicated in prior LERs (e.g., 311/90-044-00). Due to those other
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating.Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 91-010-00 5 of 5 r
CORRECTIVE ACTION: (cont'd) events, sever~l syste~ design modifications are being considered to eliminate the spurious ESF actuation signals. These design modifications include a proposal for RMS channel equivalent replacement.
The 2R45C detector assembly was replaced. The channel was declared operable and Technical ~pecification 3.3.3.1 Action b26 was exited on July 26, 199i at 0430 hours0.00498 days <br />0.119 hours <br />7.109788e-4 weeks <br />1.63615e-4 months <br /> upon successful completion of a cha~nel functional test.
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General Manager Salem Operations
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MJP:pc SORC Mtg..91-084