05000280/LER-1975-011, Suppl to LER 75-11/01T:on 750416,pinhole Leak Developed in Recirculation Line on Charging Pump 2-CH-P-1C Causing Ventilation Vent Sampler RMS-VG-109 to Alarm.Leak Found & Isolated

Suppl to LER 75-11/01T:on 750416,pinhole Leak Developed in Recirculation Line on Charging Pump 2-CH-P-1C Causing Ventilation Vent Sampler RMS-VG-109 to Alarm.Leak Found & Isolated

ML20086Q634
Person / Time
Site:	Surry
Issue date:	07/10/1975
From:	Stallings C, Sweeney E VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20086Q639	List: 05000280/LER-1975-011, Suppl to LER 75-11/01T:on 750416,pinhole Leak Developed in Recirculation Line on Charging Pump 2-CH-P-1C Causing Ventilation Vent Sampler RMS-VG-109 to Alarm.Leak Found & Isolated
References
LER-75-11-01T, LER-75-11-1T, NUDOCS 8402280016
Download: ML20086Q634 (5)

LER-2075-011, Suppl to LER 75-11/01T:on 750416,pinhole Leak Developed in Recirculation Line on Charging Pump 2-CH-P-1C Causing Ventilation Vent Sampler RMS-VG-109 to Alarm.Leak Found & Isolated

Event date:
Report date:
2802075011R00 - NRC Website

text

s LICENSEE EVENT REPORT supplemental IIeport A0-SI-75-ll

,V CONTROL DLOCK:l l l l l l EASE PnlNT ALL RECUIRED INFORMATION) 1 6

' LEENff E LEENSE EVENT NAME LICENSE NUMBEP T Y PE TYPL 01 7 89 l vl Al Sl pl Sl1 l 14 l 0 l 0 l-l 0l 0l0 l0 l 0 l-l 0l 0l 15 25 l4l1 26 l1l1l0l 30 l0-l1l 31 32 CAT EGORY TYP SU DOCKET NUMBER EVENT DATE REPORT DATE O 1 CON'T l_' i lOl lT l lL l l 0 l 5 l 0 l - 10 l 2l 8l0 l l 0 l 4 l 1l 6l 7l 5l l0 l7 l1l 0l 7l 5l 7 8 57 58 59 60 61 60 69 74 75 80 EVENT OESCRiPTION o lDuring normal operation a " pinhole" Icak developed in the recirculation line on l 7 89- 80 M l charging pump 2-Cll-P-lC, causing the ventilation vent sampler (PJIS-VG-109) to alarm. l 7 89 80 35 lThis resulted in an unplanned release of radioactive material from the site. The l 7 89 80 EE l leak was found and isolated 30 minutes after the alarm occurred. l 7 89 80 BE l A0-SI-75-11 l 7 09 pmg 80 SYSTEM CAUSE COMrONENT COMrONENT CODE CODE COMPONENT CODE SUPPUER MANUFACTUF(R VOLATON ME lp l c l (E_l l Pl 1lP lE l Xl X] lN l lZ l9 l9 l9 l lNl 7 09 10 11 12 17 43 44 47 48 l i

CAUSE DESCRIPTION

@ lA two inch stainless steel line (Type A312-TP304) developed a small pinhole Icak at l 7 89 80 ll la weld causing the leakage of radioactive liquid. l 7 89 80 MI l' STA S  % POWER OTHER STATUS D SCO ERY DISCOVERY DESCRIPTON 1

7 8 9 lEl l1l0l0l l N/A l lAl lN/A l 10 12 13 44 45 46 80 ACTIVIIY CONTE NT RELEASED AMOUNT OF ACTMTV LOCATION OF RELEASE 7 0 9

[Jij OF (JMJ 10 RELEASE 11 l uCi 897.2 l 44 45 l Auxiliary building vent to atmosphere 80 l

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTON Q l0l0l0l 7 09 11 QJ 12 l N/A 13 l

80 PERSONNEL INJURIES NUMBE R DESCRPTON ll l0l0l0l l N/A l 7 89 11 12 80 OFFSITE CONSEQUENCES

@ l The health or safety of the public was not offected. l 7 89 80 LOSS OR DAMAGE TO FACILITY TYPE DESCRIPTON DE ( 4] _l N/A ~ l' 7 89 10 80_

PUDLICITY Ql 7 uo N/A _ ~~ .l 8402280016 750710 80 ADOITIONAL FACTORS PDR ADOCK 05

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NAME:-- E. M. Sweeney , Jr . PHONt: (804) 357--3184

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l SUPPLEMENTARY INFORMATION ON AIRBORNE PARTICULATE ACTiVlTY RELEASE AllNORMAL OCCURRENCE A0-SI-75-11 At approximately 0100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> on April 16, 1975, the Vcutilation Vent Sample (RI-VG109) alarmed indicating a high airborne particulate activity in the auxiliary building general area exhaust. At approximately 0130 hours0.0015 days <br />0.0361 hours <br />2.149471e-4 weeks <br />4.9465e-5 months <br /> a pinhole leak was discovered on the charging purup recirculation line for 2-Cll-P-lC. The recirculation line isolation valve was immediately shut and a piece of protective clothing was wrapped around the leaking pipe to stop the dispersion of reactor coolant into the air. At approximately 0200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> the affected charging pump (2-Cll-P-lC) was isolated and drained thus completely stopping the leak. It is conservatively estimated that a maximum of 25 gallons of reactor coolant leaked from the charging system. An inspection of the Ventilation Vent Particulate radiation monitor chart (R1-VG103) shows that airborne particulate activity was released from the site for about one hour.

The identity and concentrations of the radionuclides actually present in the Ventilation Vent as a result of this leak were not determined. Therefore, it is ascumed that all activities normally present in the charging system were present during the leak and in their normal concentrations. It is also assumed that 10 per cent of the particulate activity in the coolant actually became airborr.e. The activities present were as follows:

FROM RADIONUCLIDE CONCENTRATI0M {pCi) MPC {10 CFR 20} {pCI.}

ml ml Cosa 1.31 x 10-3 2 x 10-9 Co60 1.73 x 10-3 3 x 10-10 Mn54 2.76 x 10-3 1 x 10-9 Na 24 4.0 x 10 3 5 x 10-9 Cs134 3.74 x 10-3 4 x 10-10 Csl37 9.44 x 10-4 5 x 10-10 Csl38 1.27 x 10-2 3 x 10-8 11 3

6.78 x 10-2 2 x 10-7 The release rates in Ci/sec for each of the above radionuclides were as follows:

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RADIONUCI.IDE RELEASE RATE {Ci/sec }

Cosa 3.44 x 10 9 Coco 4.54 x 10-9 Mn 54 7.24 x 10-9 Na2 1.05 x 10-8 Cs l34 9.82 x 10 9 Cs l37 2.48 x 10-9 Cs 130 3.33 x 10-8 113 1.78 x 10-7 Technical Specification 3.11 requires that the controlled release rate of airborne particulate activity be governed by thc. following relationship:

EQ i gwcy 1 2.0 x 105 m3 sec Q1 is the release rate of any radionuclide i HPCi is the maximum permissible concentration of any radionuclide i f rom Appendix B, Table II of 10 CFR 20. MPCi must be reduced by a factor of 700 for any halogen or particulate activity with a half life of greater than eight days. Q1 for each radionuclide released was as follows:

(MPG)1 i m3 RADIONUCLIDE

(" i CoS8 1.20 x 103 Co60 1.06 x 104 Mn5te 5.06 x 103 Na24 2.10 Csl 3 1.72 x 104 Csl37 3.47 x 103 Cs138 1,11 113 .89 k

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• *" b' EQ 3 = 3.75 x 10 4 _m 3 or 19 per cent of the IJmit listed in Technical (MPC)i Specification 3.11 averaged over the one hour period of the release.

The calculated concentrations of radionuclides within the Ventilation Vent System were as follows:

RADIONUCLIDE CONCENTRATION {pCi}

ml CoS8 10.4 x 10-11 Coco 13.8 x 10-11 Mn 54 21.9 x 10-11 Na 24 3.2 x 10-10 Cs l34 29.8 x 10-11 Cs l37 7.5 x 10-11 Cs 136 10.1 x 10-10 H3 5.4 x 10 10 The limits in Technical Specification 3.11 are based on the highest annual average value of X/Q which will occur at the site boundary (5.0 x 10 6 seconds per meter3 ) . Therefore, the maximum allowable discharge rate (MADR) of radio-nuclides is given by:

MPC i 4.238 x 108 {Ft3}

MADR = E xL=

Concentration i x E Concentration i MIN MPC f This results in a maximum allowabic discharge rate of 2.45 x 10 8 Ft3, Puring the release, the Ventilation System flow was 7 x 104 Ft3 or MIN

.03 per cent of the maximum allowable. M1N It can be seen from the above calculations that the health and safety of the general public was not affected.

Two small coolant leaks have previously occurred in the charging pump re-circulation lines at Surry. A detailed investigation into the cause of these leaks was conducted by Vepco's engineering staff and representatives of the nuclear steam supplier. At present, the cause appears to be related to hydraulic crosion and/or cavitation in the recirculation piping. The nuclear steam supplier has committed to evaluate this prob 1cm and establish a final recommendation for implementation at Surry Unit Nos. 1 and 2. To date this information has not been provided.

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\0 Mr. Norman C. Moseley, Director Scrial No. 512-S Office of Inspection and Enforcement P0&M/JTB:clw United States Nuc1 car Regulatory Commission Region II - Suite 818 Docket Nos. 50-280 230 Peachtree Street, Northwest License Nos. DPR-32 Atlanta, Georgia 30303

Dear Mr. Moscicy:

Pursuant to Surry Power Station Technical Specification 6.6.B.1, the Virgini,a Electric and Power Company hereby submits forty (40) copies of Abnormal Occurrence Report No. A0-SI-75-11.

The substance of this report has been reviewed by the Station Nuclear-Safety and Operating Committee and will be placed on.the agenda for .the nsxt meeting of the System Nuclear Safety and Operating Committee.

Very truly yours, lu .%b AY -

C. M. Stallings Vice President-Power Supply and Production OperationsJ Enclosures 40 copics of A0-SI-75-11 cc: Mr. K. R. Goller r Mr. Bryce P. Schofield l

Lirector, Bureau of Industrial llygiene

. [ () # 1 yc( c v $2l5 l

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