ML17347A608

LER 87-025-00:on 871012,containment Vent & Control Room Ventilation Isolation Actuated.Caused by High Levels of Rb-88 in Containment Following Unit Shutdown.Containment Activity Level Returned to normal.W/871112 Ltr

ML17347A608
Person / Time
Site:	Turkey Point
Issue date:	11/12/1987
From:	Wager V, Woody C FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
L-87-463, LER-87-025-01, LER-87-25-1, NUDOCS 8711170113
Download: ML17347A608 (6)

Text

REGULA i u Y INFORMATION DISTR IBUTI, SYSTEM (R IDS)

ACCESSION NBR 8711170113 DOC. DATE: 87/1 1/12 NOTARIZED: NO DOCKET FACIL: 50-251 Turkey Point Planti Unit 4i Florida Power and Light C 05000251 AUTH. NAME AUTHOR AFFILIATION WAGER'. Florida Power 5 Light Co.

WOODY'. O. Florida Poeer 5 Light Co.

RECIP. NAME RECIPIENT AFFILIATION

SUBJECT:

LER 87-025-00: on 871011. containment vent h control Toom ventilation isolation. Caused bg high levels of Rubidium in containment following unit shutdown. Containment activity level returned to normal levels. W/871112 ltr.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR TITLE: 50. 73 Licensee Event Report (LER)i Incident Rpti g ENCL J. SIZE:

etc.

NOTES:

REC IP IENT COPIES REC IP IENT COPIES

', ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 PD2-2 PD 1 1 MCDONALD' 1 1 ACRS MOELLER 2 I INTERNAL: ACRS MICHELSON 1 1 AEOD/DOA 1 1 AEOD/DSP/NAS 1 1 AEOD/DSP/ROAB 2 2 *EOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEBT/ADS 1 0 NRR/DEST/CEB 1 1 NRR/DEST/ELB 1 1 NRR/DEST/ I CSB 1 NRR/DEST/MEB 1 NRR/DEBT/MTB 1 1 NRR/DEST/PSB 1 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 NRR/DLPG/GAB 1 NRR/DOEA/EAB 1 NRR/DREP/RAB 1 1 NRR/DREP/RPB 2 2 f8%)R. S IB 1 NRR/PMAS/ILRB 1 1 REG FILE 02 1 1 RES DEPY QI 1 RES TELFORDe J 1 1 RES/DE/EIB 1 1 RQN2 FILE 01 1 1 EXTERNAL. EQ8cG GROHI M 5 5 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 NSI C HARR ISs J 1 1 NSIC MAYSI G 1 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44

NRC Form 345 U.S. NUCLEAR REOULATORY COMMISSION (943)

APPROVED OM8 NO. 31504104 EXPIRES: 4/31/45 LICENSEE EVENT REPORT ILER)

FACILITYNAME (1) DOCKET NUMSER (1) P Turkey Point Unit 4 o s o o o 251 1 OF Containment and Cont/ro'L Rooq Ventilation so a )on ue o sg Leye]s of Rubidium 'in Containment Following Unit Shutdown EVENT DATE (4) LKR NUMSKR (Ci REPORT DATE 17) OTHER FACILITIES INVOLVED (Cl o~ UcNTIAI OAY YEAR DOCKET NUMSERISI MONTH DAY YEAR YEAR NUMCCR MONTH NUM>> ~ II Turkey Point Unit 3 0 6 0 0 0 8 7 8 0 2 5 001 11 8 7 N/A 0 5 0 0 0 THIS REPORT IS SUSMITTED PURSUANT TO THE REQUIREMENTS OF 10 CF R (I: /Check one or moro of the foll nyfnf/ (1'll OPERATINO MODE (4) 20A02(C) 20AOS( ~ ) 50.73(el(2)(lr) 73.7)(c) 20A05(e) l1)(0 50M(e)(11 50.73(el(1) 4) 73.71(c)

LEVEL P 0 P 20A05(e) III(CI 50M(~ I(21 50.734)(2) (rC I OTHER /Specify /n Aortrect Pelow end ln Tent, ff/IC Perm 20A05(e) (1)DII) 50.73(e)(21(II 50.734) (1)(r)CI(AI 1FBA/

20A05(e) (1((lrl 50.734) (2) I 4) 50.734) (2) (rCI I (S I 20A05 (e) (I ) (r) 50.734)(2I(IIII 50.73( ~ I(2)(cl LICKNSEE CONTACT FOR THIS LER 112)

NAME TELEPHONE NUMSER AREA CODE Virgil Wager, Licensing Engineer 3 05 246 -64 76 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRISKD IH THIS REPORT (13)

EPORTASLE vp w 'h COMPONENT MANUFAC MANUFAC, EPORTASL CAUSE SYSTEM TURfR TO NI'RDS CAUSE SYSTEM COMPONENT TURER TO NPRDS N

...Cl . Cc I L R I T 260 I/PPLKMKNTALREPORT EXPECTED (le) MONTH DAY YEAR EXPECTED SU4MISSION DATE 115)

YES /lf y<<, complete EXPECTED SUBMISSION DATE/ X HO ASSTRACT (Llmlt to /400 eoecet, /A, epproefmetrfy fifteen tlnffenpece typcrw(t<<n line>>l 115) unactuated On October 12, 1987, at 2015, with Unit 4 in Mode 3, Process Radiation Monitor (PRM) R-ll, Containment Radioactive Particulate Monitor, containment vent and the control room ventilation isolation.

R-12, the Containment Radioactive Gaseous Monitor was verified to be reading normal. A particulate grab sample was taken, and a leak rate calculation was initiated. The particulate grab sample showed a higher than expected radiation level, which was mainly due to Rb-88. The results of the leak rate calculation indicated there was no unexpected RCS leakage . The containment activity level returned to normal levels by approximately 0100, October 13. An investigation of the increased level of Rb-88 radiation identified that the time of the increase coincided with the depressurization of the RCS, and with an increase in iodine activity in the RCS. Based on this, the likely cause of the higher than normal activity was a rapid unit shutdown and subsequent depressurization, due to a hurricane warning. This was exacerbated by a known leak in the fuel cladding. As Dose Equivalent Iodine level is .considered to be an indicator of fuel cladding leakage, it will continue to be closely monitored when the unit goes critical, and during subsequent power operation.

PDR ADOCH, 05000 OO251 S

NRCF otm 345 (903I

NRC Fmm 3EEA (943) UA. RC/CLEAR REOULATORY COMMISSION LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AFFROVEO OMB NO. 3150-O)04 EXFI RES; 8/31/BB FACILITYNAME (tl DOCK ET N(/MBER (3)

LER NUMBER (e) FACE (3)

YEAR NW 5EOUENTIAL NUMBER

~ REV)5)ON

~~~'UMEER TEXT //F mom Turkey Point Unit 4

<<ear /F mEUFNE use <<NR/o45//YRC Avm 3(ELE'g/ (IT) o e o o o 25], 025 0002O03 4

On October 12, 1987, at 2015, with Unit 4 in Mode 3 (Hot Standby), Process Radiation Monitor (PRM) R-ll, Containment Radioactive Particulate Monitor, (EIIS:IL) increased above its setpoint and actuated the containment vent and the control room ventilation isolation logic. The containment vent isolated and the control room ventilation isolatec( and switched over to the recirculation mode, per design.

No,personnel were inside the containment building at this time.

The unit was shut down earlier that day at 1348, as a precautionary measure, because a hurricane warning was in effect for southeast Florida at that time.

Following the actuation, R-12, the Containment Radioactive Gaseous Monitor was verified to be reading normal levels of radiation. A particulate grab sample was taken, and a leak rate calculation was initiated. The particulate grab sample showed a higher than expected radiation level, which was mainly due to Rb-88. The activity level at the time of the R-11 actuation was determined to be 7.67E-07 uc/cc when the analysis results were backMecayed. The expected level under normal operation is approximately 5.0E-08 uc/cc. The results of the leak rate calculation indicated there was no unexpected Reactor Coolant System (RCS) (EIIS:AB) leakage .

The containment activity level returned to normal levels by approximately 0100, October 13.

CAUSE OF EVENT An investigation of the increased level of Rubidium-88 radiation identified .that the time of the increase in the Rb-88 particulates coincided with the depressurization of the RCS, and with an increase in iodine activity in the RCS.

Based on 'this, an evaluation performed by the Chemis'try Department stated that the likely cause of the higher than normal activity was the rapid unit shutdown and subsequent depressurization due to the hurricane warning<< This was exacerbated by a known leak in the fuel cladding. The leak in the cladding did not exceed any Technical Specification limits.

ANALYSIS OF EVENT The containment vent and the control room ventilation isolation functioned per design. There was no release from the containment to the environment, nor were personnel present in the containment at the time of the event . An RCS leak rate calculation was performed and the results showed no unexpected RCS leakage. Based on the above the health and safety of the public were not affected .

NRC FORM 555A (943)

~ e ~

NRC Form 388A U.8. NUCLEAR REOULATORY COMMISEIOH (9431 LlCENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OM8 NO 3180M((H EXPIRE8: 8/31/88 FACILITYNAME (tl DOCKET NUMEER 131 LER NUMEER (El PACE ll) o: EEOUENTIAL AKvreroN YEAII NUM Err NUM err Turkey Point Unit 4 o s o o o 251 87 025 00 03 OF 0 3 TEXT /I/more <<>>oe /e ~ /r/rerL rree ///O 'ore/I NRC Arm 388A8/ (171 CORRECTIVE ACTIONS

1) R-12 was verified to not be showing increased gaseous activity.

2) A particulate grab sample vas taken.

3) A leak rate calculation was performed, with satisfactory results, indicating that the increased activity was not due to unexpected leaks')

As Dose Equivalent Iodine level is considered to be an indicator of fuel cladding leakage, it vill continue to be closely monitored vhen the unit goes critical, and during subsequent power operation.

ADDITIONAL DETAILS Similar Occurrences: None NIIC FOIIM 388A (NQI

P OX 14000, JUNO BEACH, FL 3340B 0420 NOVEMBER t 2 $ 9S7 L-87-463 IO CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No. 50-25 I Reportable Event: 87-25 Date of Event: October l2, I 987 Containment and Control Room Ventilation Isolation Due to Hi h Rubidium in Containment Followin Unit Shutdown The attached Licensee Event Report is being submitted pursuant to the requirements of IO CFR 50.73 to provide notification of the subject event.

Very truly yours, C. O. Wood Group Vi resident Nuclear Energy COW/SDF/gp Attachment cc: Dr. J. Nelson Grace, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant an FPL Group company SDF I /063/ I