ML19210A157

Event Rept 76-1/1T:on 760102,leakage of Valve WDL-V125 Caused Unplanned Radiation Release.No Tech Specs Limits Exceeded.Concentration of Effluent Released to River 3.3%,as Specified in 10CFR20

ML19210A157
Person / Time
Site:	Three Mile Island
Issue date:	01/12/1976
From:	Arnold R METROPOLITAN EDISON CO.
To:
References
GQL-0052, GQL-52, NUDOCS 7910240882
Download: ML19210A157 (4)

Text

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DATE OF DOC DATC REC'O

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ENCLO3URES-Letter trans the following........

Event Report # 76-1, on 1-2-76, Concerning an Unplanned Release of Radioactibe Material..

(1 Cy. Received)

.PLANT NAME:

Three Mile Island 9 1 FOR ACTIOW/INFC RIAATION SAR 1_2n_76 e.~..:acur.=

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'~c$Y-g-y-s PHONE.3601*POST OFFICE BOX 542 READING PENNSYLVANI A 19603-g (NRC FUBUC DOCUN M)x"Regulaterf t ,..'n s 3-~January 12, 1976

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-'GCL 0052'^,c;.<.1.-, g/..)--Dh[ t; _ ~ ' ['l/

_~Director of Nuclear Reactor Regulation U.S. Nuclear Reg tlatory Cc==issic..

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Dear Sir:

.tu-Docket No. 50-289 Operating License DPR-50 Event Report 76-1/lT In accordance with Section 6.7.2.a.2 of the Technical Specifications for our Three Mile Island Nuclear Station Unit 1, enclosed please find Event Report 76-1/lT that deals with an unplanned release of radioactive naterial wh4 ch occurred on January 2,1976.

We would like to point out that no member of the public and no staticn or contractor personnel received a radiation dose in excess of the limits stated in 10 CFR 20 as a result of the release.

Further, none of the limits given in the Technical Specificaticns were exceeded.

'de trust that this satisfies the reperting requirements referenced above and adequately ansvers any concerns you may have.

Sincerely, 9/'.1 w r'~-R. C.y.Arnold Vice President RCA:JMC :pa Encle:,ure : Event Report 76-1/1T cc: Sh. J. P. O'Reilly, (U.S. NRC - Region 1)

Ms. Margaret Reilly (Pa. DER) 42S 1490 088

.. ~.EVFJT REPCRT 76-1/1T REPORT OF AU UNPLANNED RELEASE OF RADICACTIVE MATERIAL OCCUERI:7G ON 2 JA:IUARY 1976 DESCRIPTICU OF CCCURRENCE:

On January 2nd , between the hours of 2005 and 2030 (twenty-five (25) =inutes) an inadvertant release of radicactive material cecurred due to leekage through val 7e WDL-V125 while recirculating the Waste Evaporator Condensate Storage Tank"3" (WDL-T113) concurrent with routine flushing of the Radicactive Liquid Discharge Mcnitor, RM-L6.

The Discharge Monitor, RM-L6 was being flushed with reclaimed (non-radicactive) water folleving a centrolled release of radicactive liquid frc= Waste Evaporator Condensate Storage Tank"A" (WLL-TilA) to decrease the amount of conta=inatien build-up in the =cnitor.

The reclai=ed water flush had been in progress for approximately fifteen (15) minutes when WOL-T113 was placed in the recirculation mode. Leakage Past Valve WDL-V125 alleved racio-active liquid to flcw frc= the recirculation path to the normal release path.

The release caused an increase in ecunt rate en the discharge =enitor, RM-L6 which was subsequently noted by Centrol Roc = personnel. The recirculation of WEL-0113 and the flushing of EM-L6 vere terminated, thereby, stopping the release of radioactive material.

APPARENT CAUSE OF OCCURREUCE:

It was believed initially that valve leakage en WDL-V125 was per=itting a s=all a= cunt of liquid to be released. Upon inspection of the valve, no degradatien of valve seating surfaces was found; therefore, it is felt that the air loading en the valve operator =ay not have been properly bled off by the auxiliary operator, thereby, permitting the valve te be " cracked" off its seat.

ANALYSIS OF CCCURRENCE:

For the following reasons it is believed that the inadvertant release en the 2nd of January did not endanger either the health or safety of the public:

A.Ncne of the limits in the TMI-1 Technical Specificatiens were exceeded.

3.The concentratien of radicactive material released to the river was a small percent (N 3.3%) of the concentratien specified in 10 CFR 20 for unrestricted areas.

CCRRICTIVE ACTION:

The corrective action as described above was taken to ter=inate the release.

Additionally, procedural changes were incorporated to preclude the recircula-tion of either of the Waste Evapcratcr Ccndensate Stcrage Tanks during the release of radicactive liquid er the rcutine flushing of RM-L6, until valve WOL-V125 could be inspected.

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._-2-'...Since the inspection of WDL-V125 disclosed no valve proble: and the valve was leak tested satisfactorily, the operating procedure vill be changed to ensure WDL-V125 (12L) is closed when ter=inating a centro 11ed release.

FAILURE EATA:

None RELFASE EATA:

Analysis of the Radicactive Liquid Discharge Monitor (RM-L6) Recorder Charts and the centents of WDL-T113 subsequent to the release indicated that a volu=e of cne hundred seventeen (117) gallens containing .0171 curies of radicactive caterial, of which .0169 curies was Tritiu=, was released at approximately k.7 GFM.The folleving Isotopes and Concentratiens were released:

ISCTOPE CCNCENTRATICN (pCi/=1)

CURIE CONTENT (pCi) 3 3.82 x 10-2 1.69 x 10 3 2 133 3.623 x 10-1.60 x 10 Xe-6 133=x, 5 025 x 10 2.22-5 135 1 322 x 10 5.85 Xe-6~1 13k 1.758 x 10 7.8 x 10 Cs 137 7.k99 x 10 3 32 Cs N 4 131 9 58 x 10 h.2 x 10 7 58 6. 97 x 10 2.877 Co It has been determined, based en the analysis of WEL-T113 and the dilution factor (4255) during the release, that the ecncentratien of radicactive material was approximately 3.3". of the release cencentration limit as specified by the TMI-1 Technical Specificatiens. Additionally, based en the alar =

setpoint of the Discharge Menitor, RM-L6, and available dilution ficv, the discharge vould have been terminated by a high alar = frc= RM-L6 prior to exceeding the release concentration li=it of the Technical Specificatien.

1490 090