ML18096A418

LER 91-019-00:on 911207,containment Radioactive Noble Gas Monitor Channel Alarmed,Resulting in ESF Actuation Signal. Caused by Inadequate Administrative Controls.Procedure Re SG Work During Refueling Activities revised.W/920102 Ltr

ML18096A418
Person / Time
Site:	Salem
Issue date:	01/02/1992
From:	Pollack M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-019-02, LER-91-19-2, NUDOCS 9201090079
Download: ML18096A418 (4)

Text

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Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station January 2, 1992 U. s. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 De.ar Sir:

SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 91-019-00*

This Licensee Event Report is .being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR 50.73(a) (2) (iv). This report is required within thirty (30} days of discovery.

Sincerely yours,

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~A. Vondra General Manager -

Salem Operations MJP:pc.

Distribution n\.Y lj l""q°t (\ I~ 't>

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The Energy People 9201090079 920102 95-2189 (10M) 12-89 PDR ADOCK 05000311.

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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (6-891 APPROVED.OMB NO. 3150*0104 EXPIRES: 4/30/92

. ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 ):IRS. 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.

I FACILITY NAME (11 DOCKET NUMBER (2) . I PAGE (3)

Salem Generati~g Station - Unit 2 o 15 I o Io I o I 31 l I ll 1 JoF o I3 TITLE (4)

ESF Signal Actuation: Cont. Vent. Isolation due t.o 2Rl2A RMS Channel Response EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) 01'.HER FACILITIES INVOLVED (BJ MONTH DAY VEAR VEAR  :\t SE~~~~~~AL Jt ~~~~~~ MONTH DAY VEAR . FACILITY. NAMES DOCKET NUMBER(SI 0151010101 l l 1 I 2 oI 1 9 1 911 - oI1 I 9 - ol o o I 1 oI2 9j2 0151010101 I I THIS REPORT IS SUBMITTED PURSUANT TO THE R~QUIREMENTS OF 10 CFR §: (Chock on* or mor* of the following) (11)

OPERATING MODE (9)

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20.402lbl 20.405(c) 60.73(1)(2)(iv) 73.71(b) 1-~~~~~'--L-~~ 1-- ~

POWER LEVEL * -

20.406(e)(1 )(i) . ........,_ 60.38(c) (1)

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60.73(1)(21(vii) ,___ OTHER (Spocify in Abstract below and In Text. NRC Form 20.406(0)(1 )(iii) 60.73(1)(2)(;) 60.73(1)(2)(viliJ(A) 366A) llllllit=

NAME 20.406(1)(1 )(Iv) 20.406(1111 JM

- 60.73(1)(2)(11) 60.73(1)(2)(iii)

LICENSEE CONTACT.FOR THIS LEA (12) f--

..60.73(1)(21(vlll)(B) 60.73(1)(2Hxl TELEPHONE*NUMBER AREA CODE

~- J. Pollack - LER Coordinator. 6 (0 I 9 3 I 31 9 1- I 210 12 I 2 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFAC*

TUR ER R~6°~~:gkE i!ii*j:_.*:i:.:!iii*:*1:::=*:*:1=::J:i/::*111.:.:j:'. CAUSE SYSTEM COMPONENT MANUFAC*

TUR ER I I 1* I I I I I I I I I I I

. !*.:.:*::*:.J=.==1:.j:.,=1*:::1:..:::=:::**:J:::l:**j I I I I I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAV YEAR EXPECTED h YES (I~ y*s, compl*t*:EXPECTED SUBMISSION DATE)

ABSTRACT (Limit tO 1400 spaces, i.e., approximately fifteen single-space typewrittBf! lines/ (161 hi NO SUBMISSION DATE (151 I I I On 12/7/91, the 2Rl2A {Containment Radioactive Noble Gas Monitor)

Radiation Monitoring System (RMS} channel al~rmed. This resulted in an Engineered Safety Feature (ESF) actuation signal for Containment Purge/Pressure-Vacuum Relief (CP/P~VR} System {BF} isolation. The channel was not declared inoperable since the c~use of the alarm was due to airborne activity above no~mal background levels. This event occurred as a result of ro~tine refueling activities. Reactor Coolant System (RCS} cover gas (containing radioactive noble gases} was pulled into Containment after t~e S/G primary manway diaphragms were removed. Portable ventilation, using HEPA filtration units, is attached to the primary cold leg manway to support S/G work. In Mode 6, the 2Rl2A channel setpoint is set at ~ 2 times background, ~s retjuired by Technical Specific~ti6n Table 3.3-6 Conditional Surveillance. Due to the background levels, prior to S/G primary manway diaphragm removai, the 2R12A channel al~~m setpoint wa~ set at 240 cpm. The 2R12A channel recorded activity levels ~p to 500 cprn after the diaphragm was removed. The procedure(s}, which address refueling activities involving S/G work, will be appropriately revised to address primary manway diaphragm removal and its affect on the 2R12A RMS.channel .

. NRC Form 366 (6-89)

LICENSEE EVENT REPORT (LER} TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 91-019-00 2 of 3 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse Pressurized Water Reactor Energy Industry Identification System (EIIS} codes are identified in the text as {xxl IDENTIFICATION OF OCCURRENCE:

Engineered Safety Feature Actuation: Containment Purge/Pressure-Vacuum Relief System isolation due to 2R12A channel response Event Date: 12/7/91 Report Date: 1/2/92 This report was initiated by Incident Report No.91-891.

CONDITIONS PRIOR TO OCCURRENCE:

Reactor Defueled - 6th Refueling Qutage; reactor vessel head on vessel DESCRIPTION OF OCCURRENCE:

.On December 7, 1991 at 0619 hours0.00716 days <br />0.172 hours <br />0.00102 weeks <br />2.355295e-4 months <br />, the 2R12A {Containment Radioactive Noble Gas Monitor} Radiation Monitoring System {RMS} {ILi channel alarmed. ~his resulted in an Engineered Safety Feature {ES~}

• actuation signal for Containment Purge/Pressure-Vacuum Relief

{CP/P-VR) System {BFI isolation. The channel was not declared inoperable since the cause of the alarm was due to airborne activity above normal background levels.

On December 7, 19.91 at 0917 hours0.0106 days <br />0.255 hours <br />0.00152 weeks <br />3.489185e-4 months <br />, the Nuclear Regulatory Commission was notified of the automatic actuation of the CP/P-VRS in accordance with Code of Federal Regulations 10CFR 50.73{b} (2) (ii}.

APPARENT CAUSE OF OCCURRENCE:

The root cause of this event is inadequate administrative controls.

The source of the 2R12A channel increase in count rate was a result of routine refueling activities.

At the time of the event, the Reactor Coolant System (RCS} level was maintained at centerline in support of Steam Generator (S/G} work. As required by procedure, the S/G primary manway diaphragms were being removed. Ventilation, using portable HEPA filtration units attached to the primary cold leg manway, is put in service. The ventilation draws suction off the RCS which contains a high concentration of noble gas activity. This activity is what caused the 2R12A channel alarm.

In Mode 6, the 2R12A channel setpoint is set at ~ 2 times background, as required by Technical Specification Table 3.3-6 Conditional Surveillance. Due to the background levels, prior to S/G primary manway diaphragm removal, the 2R12A channel alarm setpoint was set at

LICENSEE EVENT RE~ORT (LER) TEXT .CONTINUATION Salem Generating Station .DOCKET NUMBER LER NUMBER PAGE.

.Unit 2 5000311 91-019-00 3 of 3 APPARENT CAUSE OF OCCURRENCE: (cont'd) 240_ cp~~ The alarm setp6int for Mode .1 through 5 operation is 20,000 cpm .. In this event, the 2Rl2A channel recorded activity levels up to 500 cpm after the diaphragm was removed.

The noble gas activity concentration in the RCS atmosphere (above the RCS coolant) is sutficient to cause an observable higher 2R12A channel count rate above.the 2R12A channel nominal alarm setpoint. Until .this activity fully disperses (and is diluted) or is purged from Containment; it can continue to cause a higher 2R.12A*channel count rate.

ANALYSIS OF OCCURRENCE:

The 2Rl2A RMS channel monitor's the radioactive noble gas content of the Containment atmosphere. An alarm signal will cause the automatic i_solation of the CP/P-VR System. The channel is used in Modes 1 through 5 in the identification of Reactor Coolant System f AB} leakage in conjunction with the containment sump level monitoring system, the containment fan cooler condensate flow rate monitors, and the containment radioactive particulate (2R11A) radiation monitoring system. In Mode 6, the 2R12A radiation monitor is used as indication of a fuel handling accident to provide early isolation of the Containment in the event of an accident.

Air samples are pulled from the Containment atmosphere through c;t filte~ paper which continuously moves past the 2~11A detecto~. The afr sam~le then passes through a charcoal cartridge (monitored by the 2R12B monitor) and is then mixed into a fixed shielded volume where it is viewed *by the 2R12A monitor. The air sample is then returned to the Containment.

• During this event, the CP/P...:.VR System valves were closed and did not change position. Therefore, the event discussed in this LER did not affect the health ~r safety of the public. However, due to the automatic actuation of an ESF system, this event is reportable in accordance with CQde of Federal *Regulations 10CFR 50~73(a) (2) (iv).

CORRECTIVE*ACTION:

The proce~ure(s), ~hich address refueling activities involving S/G work, will be appropriately revised* to address primary manway diaphragm removal and its affect on the 2R12A RMS-channel-.*

~cJt?oL#

G~~l Manager -

Salem Operations MJP:pc SORC Mtg.92-001