ML18096A434

LER 91-014-01:on 911010,containment purge/pressure-vacuum Relief Sys Isolated Due to Failure of 2R12B Channel.Channel Removed from Svc & Being Replaced W/More Reliable Equipment During Current Sixth Refueling outage.W/920109 Ltr

ML18096A434
Person / Time
Site:	Salem
Issue date:	01/09/1992
From:	Pollack M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-014, LER-91-14, NUDOCS 9201160135
Download: ML18096A434 (5)

Text

I '

PS~G Public Service Elecfric and Gas Company P.O. Box 236 Hancocks. Bridge, New Jersey 08038 Salem Generating Station January 9, 1992 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING s*TATION LICENSE NO. DPR-75 DOCKET NO. 50-311 UNIT NO. 2 SUPPLEMENTA~ LICENSEE EVENT REPORT 91-014~01

_This Licensee Event Report supplement is being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR50.73.

It addresses a second Radiation Monitoring System channel f~ilure (same channel) which occurred approximately one (1) month after the first event (addressed by the original LER). The reporting delay has been discussed with the NRC Resident Ihspector.

Sincerely yours, C. A. Vondra General Manager -

Salem Operations MJP:pc Distribution The Energy People 95*2189 (10M) 12-89

NRC. FORM 366 16-891

• e U.S. NUCLEAR REGULATORY COMMISSION e APPROVED OMB N0.3150-0104 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 IP-5301, U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO

• THE PAPERWORK REDUCTION PROJECT 13150-0104), OFFICE

' OF MANAGEMEN.T AND BUDGET, WASHINGTON, OC 20503.

FACILITY NAME (1)  !*DOCKET NUMBER (21 I PAGE 131 Salem Generating Stati.6n TITLE (4)

- Unit 2 o I 5 I o *I o I o I 3 11 111 1 loF 0 14 ESF Signal Actuation: Containment Vent. Isolation Due To 2Rl2B Channel Failure EVENT DATE 151 LER NUMBER (61 REPORT DATE 171 .. OTHER FACILITIES INVOLVED (Bl MONTH DAY YEAR YEAR tt? SEQUENTIAL NUMBER b\ REVISION NUMBER MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER ISi 0 Is Io I o I o I I I 1\ 0 llo 9 1 9 \1

- ol 114

- ol1 ol1 a I9 9'2 01S1010101 I I OPERATING THIS REPORT IS SUBMl_TTED PURSUANT TO THE R~QUIREMENTS OF 10 CFR §: (Check one or more of the lo/lowing) 1111 MODE (9) 1 20.402(b) ....__ 20.405lc) ,_ x 50,73loll21(iv) ......_ 73.71(bl POWER.

I11 o 1 b ......_ 20.4051*111)111 50.3Blcl 111 50.73loll2llvl 73.71(c)

LEVEL (101 20.4051*111 lliil ,____ 50.36lcll21 ......_ 50,73(oll2llviil

- OTHER (SpBcify in Abstract bB/ow and in Tt1xt, NRC Form 1111~1111i1111111 20.405(oll1 llilll 50.731*112llil 50.73lal 12llviil!IAI 366AI 20.405(*111 llivl

- 50.73(*112lliil 50.73lall21 lviiil IBI

- 20.406(*111 llvl

- 60.73(*112llilil 50.731*11211*1 I LICENSEE CONTA_CT FOR THIS LER (121 NAME TELEPHONE NUMBER AREA CODE -

M. J. .Pollack - LER Coordinator 610 19 313 19 1-12 b 12 12 COMPLETE ONE *LINE FOR EACH COMPONENT FAILURE.DESCRIBED IN THIS REPORT 113)

CAUSE SYSTEM COMPONENT MANUFAC-TUR ER REPORTABLE :;::;::-:=::*:- :;:;:-:* :*:* :*:*

TO NPRDS  ;:;:::::=::=:=: *:*:

-:*: CAUSE SYSTEM COMPONENT MANUFAC*

TUR ER REPORTABLE TO NPRDS ':ij .i!ji',i*J:*:i:~": : ,*: : ,:,:,):! ;fi:i::l::

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SUPPLEMENTAL RE.PORT EXPECTED 1141 MONTH DAY YEAR EXPECTED n ~

SUBMISSION DATE !151 YES l/f yes, complete .EXPECTED SUBMISSION DATE} NO .1 I I ABSTRACT (Limit to 1400*spsces, i.B., approximately fifteen single*SIJBCB typewritten lines} (16)

On October 10, 1991, at 0138 hours0.0016 days <br />0.0383 hours <br />2.281746e-4 weeks <br />5.2509e-5 months <br />, the 2R12B (Containment Radioactive Iodine Monitor) Radiation Monitoring System (RMS) channel failed low.

This resulted in an Engineered Safety Feature (ESF) actuation signal for Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System isolation. The channel was declared inoperable. At the time of the event the CP/P-VR System valves were closed. A functional check of the 2R12B channel did not reveal any faile<;l components. The channel was observed for two ( 2) weeks, while its output functions were blocked, with no additional failures. The channel was subsequently returned to service. On November 19, 1991, at 1743 hours0.0202 days <br />0.484 hours <br />0.00288 weeks <br />6.632115e-4 months <br />, the 2Rl2B RMS *channel again failed low resulting in an actuation signal for CP/P-VR System isolation. The channel was declared inoperable. At the time of the event the CP/P_:VR System valves were closed. The root cause of both events has been .attributed to equipment design. The detector system used for the Salem Unit 2 RMS channels is manufactured by Victoreen.

Periodic problems *with this system have been experienced as indicated in prior LE Rs ( e. g ~ r 311/90-010-00, and 311/91-007-00) . The 2R12B detector uses a Vic tore en Hodel 843-34 Scintillatqr. The Victoreen RMS channels are subject to vol t_age transients. After the November 19, 1991 event, the channel was removed from service. It was not returned to service. The channel l.S being replaced with more reliable equipment during 1;:he current 6th refueling outage.

NRC Form 366 16-89)

• '--.  :---------~------. *-*-*-*- -----****----:-------.

LICENSEE EVENT REPORT (LER) TEXT CONTI~UATION

.. salem--Genera ting-Sta ti on * - *-----DO-CKET-:-NUMBER-* **- *** LE-R-NUMBER * ----

!l_11t..t__2______________________ ---* ____________?_Q.9_Q_'.HJ._____ _ _ ______ 91_:-.014-__QJ____ ____A__g_:t 4 ___ _

---

PAGE -----

. PJ:,ANT_b.ND * ~Y~'.r_EJ1_TI)_JiJ~J'J_F_'_IC::b.'J:'IQN:

Westinghouse - Pressurized Water Reactor Energy Industry Identification System (EIIS) crides are identified in the text as {xx.I IDENTIFICATION OF Q~~URRE_l'{G_~_:_

Engineered Safety Feature sign~l actuations; Containment Purge Pressure-Vacuum Relief isolation, due to equipment design Event Dates: 10/10/91 and 11/19/91 Report Date: 1/09/92 This report was _initiated by Incident Report Nos.91-706 and 91-845.

CON_J)_J:_'!'IO_NS PRIQB._ TO _OC::_C:_llRB:?N.:C:E:

10/10/91: Mode 1 Reactor Power 100% - Unit Loa*a 1160 MWe 11/19/91~ Mode 5 (Cold Shutdown); 6th Refueling Outage in progress as of 11/9/91

• -DESCRIPTION OF OCCURRENCE:

--*--*~-------*--*---------**-*-- - ---

On October 10, 1991, at 0138 hours0.0016 days <br />0.0383 hours <br />2.281746e-4 weeks <br />5.2509e-5 months <br />, the 2R12B {Containment Radioactive Iodine Monitor) Radiation Monitoring System (RMS) {IL}

channel failed low. This resulted in an Erigineered Safety Feature (ESF) actuation signal for Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System {BF! isolation. The chantiel was declared inoperable. At the time of the event the CP/P-VR System valves were closed.

A functional check of the 2R12B channel did not reveal any failed components. The channel was observed for two (2) weeks, while its output functions were blocked, with no additional failures. The channel w~s subsequently returned to service.

On November 19, 1991, ~t 1743 hours0.0202 days <br />0.484 hours <br />0.00288 weeks <br />6.632115e-4 months <br />, the 2R12B RMS channel ag~in failed low resulting in an actuation sign_al for CP/P-VR System isolation. The channel was declared inoperable. At the.time of the event the CP/P-VR System valves were closed.

After the November 19, 1991 event, the channel was removed from service. It was not returned to service. The channel is being replaced with more reliable equipment during the current Gtb refueling outage.

The Nuclear Regulatory Commission was notified, on October 10, 1991, at 0200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br />, and on November 19, 1991, at 1825 hours0.0211 days <br />0.507 hours <br />0.00302 weeks <br />6.944125e-4 months <br />, of the CP/P-VR system actuation signals in accordance with Code of Federal Regulations 10CFR 50. 72 (b) (2) (ii).

LICENSEE EVENT REPORT (LER}.TEXT*CONTINUATION

• • ----------*----------------***-*------.------------* **-**-----*---* *----- ***-*- -*--- --- - -* - **- ---*~--

Sal em Generating Station DOCKET NUMBER LER NUMBER PAGE

. !!_!!it--~---- -**-------**-------5000:31_1-c_~-----*-----~J-_Ql.4_:::-_QJ________ - ___ 3 _g_t 4 The root cause of both events has been attributed to eqriipment

• design. The detector system used for the Salem Unit 2 RMS channels is manufactured by Victoreen. Periodic problems with this system have been expe~ienced as indicated in prior LERs (e.g.,

• 311/90~010-00, and 311/91-007-00). The 2R12B detector uses a .

Victoreen Model 843-34 Scintillator. The Victoreen RMS channels are subject to voltage transients.

ANALYSIS OF OCCURRENCE:

Isolation of the CP/P~VRS is an ESF. It mitigates the release of radioactive material to the ~nyironment after a design base accident.

The 2R12B RMS channel monitors the radioactive iodine gas content of the Containment atmosphere; By design, either a "high alarm signal or a low channel failure will cause automatic isolation of the CP/P-VR System. At the time of the events, the CP/P-VR valves were closed.

Air samples a~e pulled from the Containment atmosphere through filter paper ~hich continuously moves past the 2Rl1A (Containment Radioactive Particulate Monitor) detector. The aii sample then passes through a charcoal cartr{dge (monitored by* the 2R12B monit6r) and is then mixed into a fixed shielded volume where it is vi~wed by the.2Rl2A (Containment Radioactive Noble Gas Monitor) monitor. The air sample is then r.eturned to the Containment.

The 2R12A-Containment Radioactive Noble Gas monitor is the channel taken credit for by the_accident analysis for monitoring Containment airborne activity to mitigate the corisequences of an accident. The 2R12A monitor has the capability of automatic isolation of the CP/P-VR System. It remained operable during the course of this event and did not in~icate any abnormal Containment airborne activity.

During these two (2) events, RCS leakage within Containment neither 1*

increased nor indicated increasing Containment activity as evidenced by the 2Rl2B corroborating RMS channels. Therefore, this event did-not affect the health or safety of the public*. However, due to the automatic actuation of an ESF system, these events are reportable in accordance with Code of Federal Regulations 10CFR 50.73(a} (2) (iv).

CORRECTIVE ACTION:

After the October 10, 1991 event, an engineering assessment was done to identify possible causes of the momentary channel failure. A functional test was conducted which checked these possible causes.

The functional test was successfull~ co~pleted without identifying a component failure. The channel was observed for two (2) weeks, with the output functions blocked, without recurrence of a channel failure. Subsequently, the channel was returned to service.

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER

---*------~------**-*--*---

• . LER NUMBER.

PAGE Unit 2 _____________ 5_()_0_()_J_l~ __________ 9'.l::--014__~01 - *-- 4_gf__ 4 Several modifications (as a result. of previous engineering investigati6n) ~re in pro~ress (including 2R12B channel r~placement this outage) to elim1nate sp~rious RMS originated ESF' actuation signals. These modifications include iristallation of an uninterruptable power supply (UPS) for Unit 2 and RMS channel equipment replacements.

Bt.4 Salem Operations MJP:pc SORC Mtg.92-003