ML18096A874

LER 92-015-00:on 920702,discovered Potential for Pressurizer PORV Loss of Control & Position Indication During Accident. Caused by Mgt/Qa Deficiency.Porv Circuits Identified as Deficient modified.W/920803 Ltr

ML18096A874
Person / Time
Site:	Salem
Issue date:	08/03/1992
From:	Pollack M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-92-015, LER-92-15, NUDOCS 9208120067
Download: ML18096A874 (5)

Text

Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station August 3, 1992 U. S. Nuclear Regulatory Commission Document control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50-272 UNIT NO. 1 LICENSEE EVENT REPORT 92-015-00 This Licensee Event Report is being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR

50. 73 (a) (2) (i) (B). This report is required to be issued within thirty (30) days of event discovery.

Sincerely yours,*

c. A Vondra General Manager -

Salem Operations MJP:pc Distribution 120055 The Enerav Peoole 9208120067 920803 PDR ADOCK 05000272 95-2189 (10M) 12-89 5 PDR

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED OMB 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 13150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) I PAGE 131

$alem Generatin9 Station - Unit 1 TITLE (4)

I0 15 I 0 I 0 I 0 I 2 17 I 2 1 OF 0 14 I Potential For Pressurizer PORV Loss of Cont~ol & Position Indication During An Accident EVENT DATE (5) LER NUMBER (6) REPORT DATE (71 OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR :tJ SE~~~~~~AL tt ~~~~~~ MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISI Salem Unit 2 o I 5 I O I o I O 13 I 111 a I 1 a 12 9 2 912 - a 11 1 s OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE R~QUIREMENTS OF 10 CFR §: (Chock ono or moro of tho following) (11)

MODE (9) 5 20.402(b)

,....__ 20.405(c) 50.73(1)(2)(iv)

,....__ 73.71(b)

POWER LEVEL I 01 0 I 0 20.406(1)(1 )(i) 20.405(1)(1 )(Ii)

,....__ 50.38lcllll 50.381cl(2) 50.73(1)(2)(v) 50.73(1)(2) lvii)

,....__ 73.71 (c)

OTHER !Spacify in Abstroct

<101 ,....__

x - ,....__ bslow tJnd in Text, NRC Form a1111=

20.405(1)(1 )(iii) 50.73(1)(2)(i) 50.73loll2Jlviii)(A) 366A) 20.405(0)(1 )(Iv) 50.73(*112)(ii) 50.73(oll2Hviii)(B) 20.406l*HllM 50,73(o)(2)1iiil

- 50.73(o)(2)(x)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE M. J. Pollack - LER Coordinator 6 I O I 9 3 I 3 I 9 1- I 2 IO I 21 2 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 113)

MANUFAC* MANUFAC*

CAUSE SYSTEM COMPONENT TUR ER TUR ER I I I I I I I I I I I I I I I I I I I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED n ~

SUBMISSION

• DATE 1151 YES (If y6S, complot* EXPECTED SUBMISSION DATE) NO I I I ABSTRACT (Limit to 1400 spactJs, i.e .* approximat11/y fifttJtJn single-space typewritten lines) 116)

On July 2, 1992, it was discovered that during certain postulated design basis accidents (inside containment steamline break, inside containment feedwater line break or loss-of-coolant accident), loss of required valve control and position indication for the PRl and PR2 Pressurizer Power Operated Relief Valves (PORVs) may have resulted. This was due to the PR1/PR2 environmentally qualified (EQ) valve limit switches and control solenoids sharing a 125 VDC circuit breaker with non EQ pressure switches. Moisture intrusion in the non EQ components could have tripped the common circuit breaker resulting in loss of valve control and position indication. The non EQ components are pressure switches which monitor the normal air supply header pressure going to the PORV. In the event there is loss of control air, the pressure switches cause air accumulators (aux air supply) to provide backup air for the PORVs. Tech.

Spec. 3.3.3.7 (both Salem Units) is applicable in Modes 1, 2, and 3. The PORVs are listed in this table. Contrary to this Tech. Spec., the PORVs position indication, via limit switch, may have become inoperable during a design basis accident. The root cause of this event is "Management/QA Deficiency". Due to inadequate design, inadequate design review, and inadequate administrative controls, these design changes were implemented without providing separation of the lE EQ components and non EQ components. Separation of the associated PORV circuits has been completed. A review will be performed to ensure there are no other cases similar to this event.

NRC Form 366 (6-89)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station D.QCKET NUMBER LER NUMBER PAGE Unit 1 5000272 92-015-00 2 of 4 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse - Pressurized Water Reactor Energy Industry Identification System (EIIS) codes are identified in the text as {xx}

IDENTIFICATION OF OCCURRENCE:

Potential for Pressurizer Power Operated Relief Valves loss of control and position indication during postulated accidents Discovery Date: 7/2/92 Report Date: 8/03/92 This report was initiated by Incident Report Nos.92-420 and 92-421.

CONDITIONS PRIOR TO OCCURRENCE:

Unit 1: Mode 5 {Cold Shutdown)

Unit 2: Mode 5 DESCRIPTION OF OCCURRENCE:

On July 2, 1992, it was discovered that during certain postulated design basis accidents (inside containment steamline break, inside containment feedwater line break or loss-of-coolant accident), loss of required valve control and position indication for the PR1 and PR2 Pressurizer Power Operated Relief Valves (PORVs) {AB} may have resulted. This was due to the limit switches and control solenoids sharing a 125 VDC circuit breaker with non environmentally qualified (EQ) components. With this configuration, moisture intrusion in the non-EQ components could have tripped the common circuit breaker, resulting in loss of valve control and position indication. This situation was discovered during preparation of an Engineering Evaluation related to EQ design classifications.

The non EQ components are pressure switches which monitor the normal air supply pressure in the headers going to the PORV.

Technical Specification 3.3.3.7 (for both Salem Units) states, "The accident monitoring instrumentation channels shown in Table 3.3-11 shall be operable." It is applicable in Modes 1, 2, and 3. The PORVs are listed in this table. Contrary to this Technical Specification, the prior configuration of the PORV's position indication, via limit s~itch, could have become inoperable during a design basis accident.

APPARENT CAUSE OF OCCURRENCE:

The root cause of this event is "Management/QA Deficiency", per NUREG 1022, "Licensee Event Report system" (i.e., potential for the loss of

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating station DOCKET NUMBER LER NUMBER PAGE Unit 1 5000272 92-015-00 3 of 4 APPARENT CAUSE OF OCCURRENCE: (cont'd)

PORV position indication during a design basis event as required by Regulatory Guide 1.97, "Instrumentation For Light-Water Cooled Nuclear Power Plants To Assess Plant And Environs Conditions During And Following An Accident").

Design modifications involving PORV enhancement were completed in 1981 for Unit 1 and 1984 for Unit 2. Due to inadequate design, inadequate design review, and inadequate administrative controls, these design changes were implemented without providing separation of the lE EQ components (limit switch upgrades) and non EQ components (pressure switches) on the same circuit without considering the possible effects during a design basis event. The pressure switches are not required to be in the EQ program since the valves can only be considered as auxiliary devices not required to mitigate accident conditions.

ANALYSIS OF OCCURRENCE:

In Modes 1, 2, and 3, the PORVs relieve Reactor Coolant System (RCS)

{AB} pressure during all design transients up to and including the design step load decrease with steam dump operation. The PORVs minimize the possibility of an undesirable opening of the spring loaded pressurizer code safety valves. However, they are not credited in the plant design basis analysis.

As stated previously, Technical Specification 3.3.3.7 requires the PORVs position indication to be operable in the event of a design basis accident. This is in addition to any of three other position indicators (i.e., tailpipe temperatures, Pressurizer Relief Tank Temperature or Pressurizer Relief Tank Pressure).

In the 125 VDC Cabinet, one circuit breaker provided power to each PORV PR1/PR2 for control, position indication and auxiliary air supply control. The pressure switches in the auxiliary air control circuit are exempt from the EQ program. Therefore, a postulated design basis accident could have caused a short circuit. This would have tripped the breaker resulting in loss of PR1/PR2 control due to the loss of power to solenoid valves, position indication, and loss of the auxiliary air supply solenoid valves.

The PORVs are not credited in the accident analysis; therefore, the health and safety of the public would not have been affected as a result of this event. However, since the accident monitoring channels for PORV position indication may not have remained operable during a postulated design basis accident, per Technical Specification 3.3.3.7, this event is reportable in accordance with Code of Federal Regulations 10CFR50.73(a) (2) (i) (B).

This concern was identified by Quality Assurance (QA) during a review of lE equipment located in harsh environments cross checked against equipment on the Environmental Equipment Master List. Those cases

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1 5000272 92-015-00 4 of 4 ANALYSIS OF OCCURRENCE: (cont'd) identified by QA have been resolved. Engineering evaluations were prepared discussing these cases.

Since 1984, the design change process controls have been significantly enhanced such that recurrence of this event is unlikely. The process now includes specialty reviews requiring Program Analysis Group (EQ engineers) interface.

CORRECTIVE ACTION:

The PORV circuits identified as deficient have been modified to separate the PRl and PR2 non EQ components from the PRl and PR2 EQ controls and indication circuits (limit switches PR1-LS1/LS2 and PR2-LS1/LS2 and associated relays).

This event has been discussed with applicable Nuclear Electrical Engineering Department personnel.

A review will be performed to ensure there are no other EQ components sharing power suppiies with non EQ components which could compromise the function of the EQ component. Additional corrective action will be taken, based upon results of the review,/~~~propriate.

~~~

General anager Salem Operations MJP:pc SORC Mtg.92-088