ML19343C340
| ML19343C340 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 07/03/1973 |
| From: | Hartley F CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-73-07, AO-73-7, CYH-2412, NUDOCS 8103100404 | |
| Download: ML19343C340 (3) | |
Text
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Cf CONNECTICUT YANKEE ATO MIC POWER COMPANY HADDAM NECK PLANT RR # 1. BOX 127E. EAST HAMPTON. CONN. o6424 July 3, 1973 CYH-2412 o
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U. S. Atomic Energy Comission hc.
Washington, D. C.
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ATTENTI0M: Director, Directorate of Licensing pgA q'.
REFERENCE:
Provisional License No. DPR-14
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Docket No. 50-213 4'/
Abnomal Occurrence 73-7 4
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Dear Sir:
As defined by Technical Specifications for Connecticut Lnkee Atomic Power Station, Section 5.3, C, the following incident involving an unplanned release of radioactive materials from the site is reported as Abnormal Occurrence 73-7.
Upon completion of repairs to a faulty purification system valve (see Abnormal Occurrence 73-6), the reactor coolant letdown and charging system was returned from an alternate to a normal mode of operation in accordance with a routine operating procedure. The low pressure letdown valve did not respond fast enough in opening and allowed the letdown high pressure relief valve to lift, venting letdown fluid to the volume control tank.
Simultaneously airborne activity in the primary auxiliary building increased and a moderate increase of main stack gaseous activity was noted.
Investi-gation revealed leakage at the inlet flange and spring housing of the let-down high pressure relief valve. The volume control system was once again realigned to the alternate mode and the faulty valve was repaired. The bellows protector gasket, the spindle guide gasket and the cap gasket were replaced. Upon completion of repairs the volume control system was realigned to the normal mode of operation.
A maximum of 20 gallons of radioactive fluid leaked from the faulty valve to the pipe-trench of the primary auxiliary building. A total of of radioactive gas containing less than.011 curies of activity
.04 ft3 was released to the primary auxiliary building and then to the main stack.
The site boundary concentrations of all released isotopes are shown in Attachment A to this report. All are well within MPC values.
A procedural error in switching from the alternate to the normal mode of volume control was detemined to be the cause of the valve gasket leakage.
I b224 f/6 5 /GG (dCf
J 2-July 3',1973 U. S. Atomic Energy Comission The routine operating procedure cor.cerning noncal and' alternate.
operation of the volume control system will be revised to prevent recurrence of this incident.
Very truly yours, A
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rtley -
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Plant Superintendent RHG/mb Attachment (1) i cc:. Mr. James P. O'Reilly, Director Region 1, Directorate of Regulatory Operations J
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ATTACHMENT A, MPC Site Boundary-Total Activity Released - mc Isotope uc/ml Concentration pc/ml
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Xe-133 3 x 10-7 4.95 x 10-11 0.983 Xe-135 1 x 10-7 1.39 x 10-10 2.77-Xe-135m 3 x 10-8 6.74 x 10-11 1.34 I-131 1.43 x 10-13
- 3.51 x 10-14
.0007 I-133 4.0 x 10-10 5.07 x 10-13
.0101 Kr 87 2 x 10-8 5.'4 x 10-11 1.02 Kr-88 2 x 10-8 1.5 x 10-10 2.98 Ar-41 4 x 10-8 8.1 x 10-11 1.61
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