ML18095A802

LER 91-006-00:on 910216,20 & 27,containment Purge/Pressure Vacuum Relief Sys Isolation Occurred & Actuation Signals Initiated by Radiation Monitor Channel.Caused by Inadequate Administrative Controls.Channel reset.W/910318 Ltr

ML18095A802
Person / Time
Site:	Salem
Issue date:	03/18/1991
From:	Labruna S, Pollack M Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-006, LER-91-6, NUDOCS 9103210001
Download: ML18095A802 (6)

Text

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Salem Generating Station March 18, 1991 U. S. Nuclear Regulatory Commission Document Control Desk

• Washington, DC 20555

Dear Sir:

SALEM GEllERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50-272 UNIT NO. 1 LICENSEE EVENT REPORT 91-006-00 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 to be issued within thirty (30) days of event discovery.

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. I Sincerely yours,

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s. LaBruna General Manager -

Salem Operations MJP:pc Distribution r::* F'[.lf~

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NRC Form 3118 (9-831

• LICENSEE EVENT REPORT (LER)

• -- U.S. NUCLEAR REGULATORY cOMMISllON APPROVED OMll NO. 3150~104

. EXPIRES: 8/31 is&

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• DOCKET NUMBER(SI 0151010101 I *I 01s1010101 I I

• THIS REPORT II SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Choclt OM or mon of lhl fol/owing} (111 OPERATING MOOE (I)

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LICENSEE CONTACT FOR THIS LER 1121 ll0.73(all2Jl*lllllll ll0.73(aJl2Jlxl TELEPHONE NUMBER AREA CODE M. J. Pollack - LER Coordinator

• 61019 313191- 12 I 01212 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRlllED IN THiii REPORT (131 .

CAUSE SYSTEM COMPONENT MANUFAC* MANUFAC*

TUR ER SYSTEM COMPONENT TUR ER I I I I I I *-1 . I I I I I I I I I I I I I I I I I.I I I I SUPPLEMENTAL REPORT EXPECTED 1141 YfAR rn MONTH DAV EXPECTED n YES (If yn, comploto EXPECTED SUBMISSION OATEI NO SUBMISSION DATE (151 I I I ASSTRACT (Limlr to r400 ipacn. l.1.. *ppro11im1trty fifrHn 1ingl1*1pac1 rypowritr.n linnJ (18)

Three Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System isolation events occurred on 2/16/91, 2/20/91 and 2/27/91. They were initiated by the lRllA Radiation Monitoring System (RMS) Containment Particulate Radiation Monitor channel. The CP/P~VR System isolation is an Engineered Safety System (ESF). On 2/16/91 and 2/20/91, the isolation valves were closed at the time of the signal actuation; they did not change position as a result of the isolation signal. On 2/27/91, Containment Purge was in progress at the time of the* signal actuation; the isolation valves closed as designed. The Unit was in Mode 5 on 2/16/91 _and 2/20/91; it was in Mode 6 during the 2/27 /91 event. Tech. Spe~. 3.9.9 Action Statement was entered after the 2/27/91 event. The lRllA channel is not required to be operable in Mode 5. The cause of the 3 CP/P-VR System isolation signal events is attributed to equipment failure. The lRllA channel circuit board contacts and the reset switch contacts were found oxidized. The root cause of tjlis event is attributed to inadequate administrative controls. Analysis of recurring failures of this RMS chan_nel and.

other RMS channels failed to adequately define appropriate preventive maintenance. The lRllA channel reset switch contacts and .the circuit board connections were cleaned. Upon successful completion of a channel check, the lRllA channel was returned to service. The Tech.

Spec. 3.9.9 Action Statement was exited on 2/28/91. As indicated in prior LERs, engineering has investigated the concerns with the Salem U-1 and U-2 RMS c:i..1.a.1n-.1.els. Dt::bign modifications include a proposal i.oi:

RMS channel equivalent replacement~

NRC f<>rm 311-5 19.fP.il

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Genera_ting Station DOCKET NUMBER LER NUMBER PAGE Unit 1 - 5000272 91-006-00 2 of 5 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 signals for Containment Purge/Pressure-Vacuum Relief System isolation from the lRllA Radiation Monitoring System channel Event Dates: 2/16/91, 2/20/91 and 2/27/91 Report Date: 3/18/91 This report was initiated by Incident Report Nos.91-103, 91-124, and 91-149.

CONDITIONS PRIOR TO OCCURRENCE:

2/16/91: Mode 5 (Cold Shutdown): gt* Refueling Outage DESCRIPTION OF OCCURRENCE:

This LER addresses three (3) Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System {BFI isolation events occurring on February 16, 1991, February 20, 1991 and February 27, 1991. All three (3) actuation signals were initiated by the lRllA Radiation Monitoring System (RMS) {ILi Containment Particulate Radiation Monitor channel.

On February 16, 1991 at 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br />, with the Unit in Mode 5, a Containment Purge/Pressure-Vacuum Relief (CP/P-VR) System isolation signal actuated as a result of a high channel spike on the lRllA channel. On February is, 1991 at 1653 hours0.0191 days <br />0.459 hours <br />0.00273 weeks <br />6.289665e-4 months <br />, the channel's sample pump and sample filter paper drive motor had been deenergized in support of outage related activities. The lRllA RMS channel is not required to be operable in Mode 5. The isolation valves were closed at the time of the signal actuation; they did not change position as a result of the isolation signal.

Initial review of the strip chart indication, for the February 16, 1991 event, indicated that the actuation may have been the result of high activity; therefore, troubleshooting was not performed.

However, subsequent review did not subs~antiate this conclusion.

On February 19, 1991 the 1R11A and 1R12A channel setpoints (alarm and warning) were changed to 2X background as per Technical Specifications in support of the upcoming Unit mode change to Mode 6 (accomplished on February 20, 1991 at 1840 hours0.0213 days <br />0.511 hours <br />0.00304 weeks <br />7.0012e-4 months <br />). The lRllA alarm setpoint was set at 5600 cpm.

On February 20, 1991 at 0203 hours0.00235 days <br />0.0564 hours <br />3.356481e-4 weeks <br />7.72415e-5 months <br />, with the Unit in Mode 5, the 1~_:;_:_]:_ (.~1ar1i.lc~ '-<i.~c.l..tax...:: t..i.~o.~LJ., .i::i=sultirL9 iJ..l c.. CP/P-""lH. S:;{bLt.lii isolatior.L

LICENSEE EVENT REPORT (LER) TEXT CONTINUAT!ON Salem Generating Station DOCKET NUMBER ~ER HUMBER PAGE Unit 1. 5000272 *91-006-00 3 of 5 DESCRIPTION OF OCCURRENCE: (cont'd) signal actuation. The alarm was believed to b~ a result of the _lower alarm setpoint setting (tefere~ce LER 272/91-010-00): therefore, troubleshooting was*not performed. However, subsequent review did not substantiate this conclusion.

On February 27, 1991 at 1735 hours0.0201 days <br />0.482 hours <br />0.00287 weeks <br />6.601675e-4 months <br />, with the Unit in Mode 6, a Containment Purge/Pressure-Vacuum Relief System (CP/P-VRS) isolation signal was initiated by the lRllA RMS channel. At the time of the event, Containment Purge was in progress. The isolation valves closed as designed upon receipt of the signal.

At the time of the February 27, 1991 event, an operator was resetting a lRllA chaimel warning alarm. The alarm signal actuated as the warning.alarm was reset. SubsGquently, a work order was initiated and cor~ective maintenance was performed.

Technical Specification 3.3.3.1 Action *22 was entered. It states:

"With the number of channels OPERABLE less than required by* the Minimum Channels OPERABLE requirement, comply with .the Action*

requirements of Specification 3.9.9."

• Technical Specification*3.9.9 Action Statement states:

I "With the Containment* Purge and Pressure-Vacuum Relief isolation system inoperable, close each of the Purge and Pressure-Vacuum Relief penetrations providing direct access from the containment atmosphere to the outside atmosphere. The provision of Specification 3. 0 ~ 3 are not applicable.*"

The CP/P-VR System isolation is considered an Engineered Safety System {ESF). Therefore, on February 16, 1991 at 0150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br />, February 20, 1991 at 0235 hours0.00272 days <br />0.0653 hours <br />3.885582e-4 weeks <br />8.94175e-5 months <br />, and February 27, 1991 at 2010 h6urs, the Nuclear Regulatory Commission was notified of the automatic actuation signals for CP/P-VR System isolation in accordance with Code of Federal Regulations lOCF,R 50.72{b) (2) (ii).

APPARENT CAUSE OF OCCURRENCE:

The cause of the three (3) CP/P-VR System isolation signal events is attributed to equipment failure. The 1R11A channel circuit board contacts ~nd the reset switch contacts were found to be oxidized.

The root cause of this event is attributed to inadequate administrative controls. Analysis of recurring failures of this RMS channel and other RMS channels failed to adequately define appro~riate preventive maintenance. Specifically, LER 272/90-001-00 required a review of the preventive maintenance program associated with the lRllA channel. The review concluded that additional preventive maintenance was not warranted due to the potential of damaging the circuit connections by the act of installing/removing circuit cards. Also, the channel components have been scheduled to

. be ~~pl~~--: ~- i~~i=;~~~ by LE~ ~72/90-034~C1.

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Statiori DOCKET NUMBER* * -LER NUMBER . PAGE Unit 1 . 5000272 91-006-00 4 of 5 APPARENT CAUSE OF OCCURRENCE: (cont'd)

LER 311/90-044-00 initiated a commitment to investigate possible interim measures which can be taken to minimize the possibility of

• channel failures (resulting in ESF actuations}. These measures are still in review. This investigation will also be used to identify and implement appropriate preventive maintenance requirements.

ANALYSIS OF OCCURRENCE:

The 1R11A, Containment Particulate Monitor, (a NaI scintillation type detector, model LFE MDSB} monitors the air particulate gamma radioactivity in the Containment atmosphere.

• In*Modes 1 through 4,

• it is used in the identification of RCS leakage in conjunction with the containment pocket sump level monitoring syste_m,. the containment fan cooler condensate flow rate monitors, and the containment atmosphere gaseous radioactivity (1R12A) RMS channel.

• An alarm signal will cause the automatic isolation of the CP/P-VRS. In Mode

~. it is used to corroborate 1R12A radiation monitor indications of a fuel handling accident to provide early isolation of the Containment in the event of an accident.

• Air samples are pulled di_rectly from the Containment atmosphere through.a filter paper which.continuously inoves past the lR!°lA scintillation detector. After the air sample passes through the filter paper, it passes through a charcoal cart~idge (moni~ored.by the 1R12B monitor) and is then mixed into a fixed .shielded volume where it. is viewed by the 1R12A noble gas monitor. The* air sample is then returned to the Containment.

Several area radiation* monitors, in addition to the 1R12A moni.tor, .

are us.ed *to corroborate* the 1R11A channel's indications. The corroborating area radiation monitors do not have isolation capabilities. They only have alarm capability. l During the 1R11A channel spikes, Containment particulate airborne activity did not increase (as indicated by the corroborating RMS channels}. These CP/P-VR System isolation signals. are the result of an equipment failure. Therefore, these events did not affect the health or safety of the public. However, due to the automatic actuation signal of an ESF system, it is reportable in accordance

.with Code of Federal Regulations 10CFR 50.73(a}(2) (iv).

CORRECTIVE ACTION:

The 1R11A channel reset switch* contacts and the circuit board connections were cleaned. Upon successful completion of a channel check, the lRllA channel was *returned to service. The Technical

~pecific~tion 3.9.9 Action Statement was exited on February 28, 1991 at 0310 hours0.00359 days <br />0.0861 hours <br />5.125661e-4 weeks <br />1.17955e-4 months <br />.

As previously committed to by LER 311/90-044-00, interim actions to limit. the number of RMS channel failures are being evaluated. These actions include review of maintenance techniques and procedures.

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1 . . 50*00212 91-006,-00 5 of 5 CORRECTIVE ACTION: . (cont'd).

As indicated in.prior LERs, engineering ;has investigated the. concerns w.ith the Salem U-1 and *u-~ RMS channels. Design modifications

.include a proposal for _RMS channel equivalent replacement.

G~neral Manager -

Salem Operations MJP:pc SORC Mtg.91-029

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