ML18107A278

LER 99-004-00:on 990411,automatic Actuation of ESF Occurred During Reactor Vessel Head Removal in Support of Refueling Operations.Caused by High Radiation Condition.Containment Atmosphere Was Monitored.With 990505 Ltr

ML18107A278
Person / Time
Site:	Salem
Issue date:	05/10/1999
From:	Garchow D, Knieriem B Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-99-004-01, LER-99-4-1, LR-N990217, NUDOCS 9905120025
Download: ML18107A278 (5)

Text

,..

-OPS~G Pu~)ic Service Electric and Gas Company P.O. Box 236

• Hancocks Bridge, New Jersey 08038-0236 Nuclear Business Unit

. . 51999

. LR-N990217 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 LER 311/99-004-00 SALEM GENERATING STATION -UNIT 2 FACILITY OPERA TING LICENSE NO. DPR-70 DOCKET NO. 50-311 Gentlemen:

This Licensee Event Report entitled "Engineered Safety Feature Actuation, Containment Ventilation System Isolation During Reactor Vessel Head Removal" is being submitted pursuant to the requirements of the Code of Federal Regulations

• • • • 1 OCFR50.73(a)(2)(iv)****

Sincerely,

<Q ,t.(I/ l ...J D. F. ~r::-v General Manager Salem Operations Attachment

/rbk C Distribution LER File 3.7 9905120025 990510 PDR ADOCK 05000311 S PDR The power is in your hands.

95-2168 REV. 6/94

NRCFORM366 (6-1998)

U.S. NU.CLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150--0104 EXPIRES 06130/2001 Estimated burden ~r resPQnse to comply with this mandatory information collection request 50 hrs. Reported lessons learned are inco~rated into the licensing process and fed bilck to Industry. Forward commen ~ardi~

burden estimate to the Records Management Branch ~ F33 , U. .

LICENSEE EVENT REPORT (LER) Nuclear R~lato~ Commission~ Washina.ion, DC 2055~1. an to the PaP.erwork edu *on Pro~ 3150-01 ~. Office of Management and BuoHet, Washin~on, DC 050 . If an information collection does not (See reverse for required number of disp ay a curren valid OMB control number, the NRC may not conduct or spqnSQr, and a person is not required to respond to, the information digits/characters for each block) collection.

FACILITY NAME (1) DOCKET NUMBER (2) PAGE(3)

SALEM UNIT 2 05000311 1 OF 4 T1TLE(4)

Engineered Safety Feature Actuation, Containment Ventilation System Isolation During Reactor Vessel Head Removal EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR I SEQUEN11AL NUMBER IREVISION NUMBER MONTit DAY YEAR FACILITY NAME DOCKET NUMBER 05000 DOCKET NUMBER 04 11 99 99 - 004 - 00 05 10 99 FACILITY NAME 05000 OPERATING THIS REPORT IS SUBMlnED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more) (11)

MODE(9) 6 20.2201(b) 20.2203(a)(2)(v) 50.73(a)(2)(1)

• 50.73(a)(2)(vlll)

POWER 20.2203(a)(1) 20.2203(a)(3)(1) 50.73(a)(2)(11) 50.73(a)(2)(x)

LEVEL(10) 0 20.2203(a)(2)(1) 20.2203(a)(3)(11) 50. 73(a)(2)(111) 73.71 20.2203(a)(2)(ii) 20.2203(a)(4) x 50.73(a)(2)(lv) OTHER 20.2203(a)(2)(1il) 50.36(c)(1) 50.73(a)(2)(v) Spec~ln Abstract below or In C Fonn 366A 20.2203(a)(2)(1v) 50.36(c)(2) 50.73('!)(2)(vll)

LICENSEE CONTACT FOR THIS LER (12) nAME TELEPHONE NUMBER (lllClude ArN Code)

Brooke Knieriem, Salem Licensing (609} 339-1782 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE CAUSE SYSTEM COMPONENT 11ANUFAC1URER REPORTABLE TOEPIX TOEPIX SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY YEAR SUBMISSION IYES (If yes, complete EXPECTED SUBMISSION DATE). xlNO DATE(15)

ABSTRACT (Limit to 1400 spaces, I.e., approxlmately 15 single-spaced typewritten lines) (16)

This LER reports the automatic actuation of an Engineered Safety Feature (ESF) due to a valid signal, as required by 10CFR50.73(a) (2) (iv). On April 11, 1999 during Reactor Vessel Head removal in support of refueling operations, the Salem Unit 2 Containment Noble Gas monitor (2Rl2A) alarmed in response to a valid high radiation condition, causing a Containment Ventilation system isolation. The high radiation condition was caused by the release of gaseous activity in the upper Reactor Vessel following plant depressurization.

Although the alarm of the 2Rl2A and the subsequent isolation of the Containment Ventilation system should be anticipated as a part of the pre-planned sequence of Reactor Vessel disassembly, procedural requirements were not in place to secure Containment purge in anticipation of a possible ESF isolation of the Containment Ventilation system.

Corrective Actions for this event included containment atmosphere monitoring and a follow-on Containment Purge to Plant Vent evolution. In addition, the Cold Shutdown to Refueling procedure, Sl/S2.0P-IO.ZZ-0007, will be revised to require that Containment purge be secured prior to lifting the Reactor Vessel Head in anticipation of a possible isolation of the Containment Ventilation system as a result of an alarm of the Containment Noble Gas monitor.

. NRC FORM 366 (6-1998)

NRC F-ORM 366A (s-1g9a1

• LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION l----:-~~-~~---'F~A~C~IL~ITY;....;._;N~A~M~E~(~1)'--~~~~~~-i~-D~O~C~K~ET:..;....;..N~U~M=B-E_R~(2~)~~~~L-E_R_N_U_M_B_E_R4(6~i)~~~1-----'P-A~G_E~C3~1)~-1i YEAR I SEQUENTIAL NUMBER I REVISION NUMBER SALEM UNIT 2 05000311 99 - 004 - 00 2 OF 4 TEXT (If more space is required, use additional copies of NRC FonTI 366A) (17)

PLANT AND SYSTEM IDENTIFICATION Westinghouse - Pressurized Water Reactor Engineered Safety Feature Actuation System {JE/-}*

Radiation Monitoring Instrumentation {IL/-}

Containment Ventilation System {BF/-}

Steam Generators {SB/SG}

Reactor Coolant System {AB/-}, Reactor Vessel {AB/RPV}

• Energy Industry Identification System (EIIS) codes and component function identifier codes appear as {SS/CC}

CONDITIONS PRIOR TO OCCURRENCE At the time of the occurrence, Salem Unit 2 was shutdown, in Mode 6 with the Reactor Coolant system depressurized. Containment closure was established to support refueling operations. Containment purge was in progress as permitted by Salem Technical Specifications.

DESCRIPTION OF OCCURRENCE On April 11, 1999 at 1535, Salem maintenance personnel began removal of the Salem Unit 2 Reactor Vessel Head {AB/RPV} in preparation for refue~ing operations. At 1554 the Salem Unit 2 Containment Noble Gas monitor (2R12A) {IL/-} alarmed, resulting in the automatic isolation of the Containment Ventilation system {BF/-}. The 2R12A monitor alarmed in response to a release of gaseous activity into the Containment when the Reactor Vessel Head was lifted from the Reactor Vessel. Operations personnel entered procedure S2.0P-AB.RAD-000l(Q), Abnormal Radiation, and all non-essential personnel were evacuated from containment. There was' no unmonitored release of radioactive gases. The Containment atmosphere was monitored and a Containment Purge to Plant Vent evolution was performed in accordance with plant procedures.

Before entry into Mode 6, on April 9, 1999 the 2R12A setpoint was reset to

~2x background as required by Technical Specification 3/4.3.3.1, Radiation Monitoring Instrument~tion, table 3.3-6. In addition, to support the refueling operations, Reactor Coolant system degassification was performed on April 4, 1999 in accordance with plant procedures to reduce the concentration of hydrogen and fission product gases.

NRC FORM 366A (6-1998)

NRC FORM 366A (6-1998)

• LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.S. NUCLEAR REGUl.ATORY COMMISSION

~-~~~~~~FA_C_IL_l_TY~NA_M_E_(~*1,__)~~~~~~-1~~DO_C_K_ET~N_U_M_B_E_R~(2~!)--i~~--.-L-E_R_N_U_M_B_E_R~(~16).__~~1-~-PA_G_E_(~3.__)-1--i YEAR I SEQUENTIAL NUMBER I REVISION NUMBER SALEM UNIT 2 05000311 99 - 004 - 00 3 OF 4 TEXT (If more space is required, use additional copies of NRC Fonn 366A) (17)

Prior to this event station personnel considered the possibility of an R12A alarm due to a noble gas release into the Containment when opening Reactor Coolant system to atmosphere. In particular,* their consideration addressed the removal of the Stearn Generator {SB/SG} rnanway covers and diaphragms, which was scheduled to occur just prior to the removal of the Reactor Vessel Head. Awareness of the possibility of Containment Noble Gas monitor alarms during Stearn Generator rnanway removal was communicated to station personnel during pre-job briefings. No specific mention of potential alarms of the 2Rl2A as a result of the Reactor Vessel Head lift was made.

CAUSE OF OCCURRENCE The cause of the isolation of the Containment Ventilation system was the release of radioactive gases from the Reactor Coolant system during removal of the Reactor Vessel Head.

PRIOR SIMILAR OCCURRENCES A review of LERs for Salem Units 1 and 2 and Hope Creek for the past two years did not identify any reportable occurrences that were caused by the release of radioactive gases from the Reactor Coolant system during removal of the Reactor Vess~l Head or other anticipated activities.

SAFETY CONSEQUENCES There were no safety consequences as a result of the event described in this LER. The function of the 2R12A is to provide containment isolation in the event of a fuel handling accident during refueling operations. During refueling operations, the 2R12A Radiation Monitor monitors the Containment atmosphere to provide indication of unexpected increases in containment airborne fission product radioactivity levels. When airborne radioactivity reaches the 2R12A alarm setpoint, the 2R12A provides an isolation signal to the Containment Ventilation system to prevent radioactive release to the atmosphere.

The isolation of the Containment Ventilation system occurred as designed to isolate the Containment atmosphere to prevent release to the outside environment. The Containment was purged to atmosphere via the Plant Vent and the monitored exhaust activities were below Technical Specification limits.

NRC FORM 366A (6-1998)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-1998)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE(3)

SALEM PNIT 2 05000311 99 - 004 - 00 4 OF 4 TEXT (If more space is required, use additional copies of NRC Fonn 366A) (~7)

CORRECTIVE ACTIONS

1. The Containment atmosphere was monitored *and a Containment Purge to Plant Vent evolution performed in accordance with plant procedures. This evolution purged the existing atmosphere through a HEPA filter and the monitored.exhaust activity was below Technical Specification limits.

2. Procedures Sl/S2.0P-IO.ZZ-0007(Q), Cold Shutdown to Refueling, will be revised by 08/31/99 to incorporate an additional step to secure Containment Purge prior to lifting the Reactor Vessel Head in anticipation of a possible ESF actuation from the R12A Containment Noble Gas monitor. (PIRS 99041101, CRCA. 01)

NRC FORM 366A (6-1998)