ML20151U654
| ML20151U654 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 05/06/1977 |
| From: | Roy G, Thompson D, Whitt K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-77-074, PNO-77-74, NUDOCS 9809110109 | |
| Download: ML20151U654 (2) | |
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1 PRELIMINARY NOTIFICATION l
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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-77-74 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.
-Facility:
Portland General Electric Company Trojan Nuclear Plant Docket..No. 50-344 (Oregon)
Subject:
' UNPLANNED RELEASE OF NOBLE GASES A representative of the Oregon Department of Energy reported to the Region V (Walnut Creek, California) office on May 2, 1977 that there had been an unplanned release of radioactive gases from the Trojan plant on Saturday night (April 30/May 1). On May 3, 4 and 5, 1977, Region V obtained additional information regarding the release from the licensee.
The unplanned release occurred during the degassing of the primary coolant system following the planned shutdown of the reactor on April 29 for maintenance purposes. The release was the result of a pressure relief valve in the radioactive gaseous waste system actuating and releasing i
an estimated 69.2 curies of noble gases to the environment via the i
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auxiliary building stack. The buildup of pressure in that part of the i
system was caused by the shutdown of the waste gas compressors due to
,e excessive pressure on the exhaust side. The reason for the, excessive
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exhaust pressure on the compressors has not yet been de'termined.
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The operator shut off the volume control tank vent, which was the j
source of the gas release, following the receipt of an alert alarm in the control room on the gaseous radwaste monitoring system. The actual release occurred over a time period estimated to be about 30 seconds.
Tht. licensee has calculated the release to be 5.1 x 10-5 uCi/cc averaged over 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and determined that technical specification limits were not axceeded. The releast. gas contained primarily xenon-133 with a little (5-6%) xenon-135. Because this is an unplanned release of more than 5 curies of noble gases, the licensee is required to submit a report of
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the occurrence within 30 days to the NRC.
The licensee issued a press release on May 3, 1977 regarding this release.
It has received local newspaper and TV coverage.
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PDR I&E
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PNO-77-074 PDR l
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Page 2 PNO-77-74 Continued May 6, 1977 Region V inspectors will examine the details of this occurrence durinC an
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inspection scheduled for the week of May 9, 1977.
NRC, Region V received 4.nitial notification of this occurrence from the Oregon State Department of' Energy, by telephone at about 10:00 a.m.
r on May 2, 1977. This information is current as of 5:00 P.M. EST May 5, 1977.
Contact:
KWhitt, IE x27261 GWRoy, IE x27261 DIhompson, IE x27541 Distribution: TransmittedHSt.):'W Chairman Rowden C. C. Kammerer, CA G. F. Murphy, JCAE Commissioner Kennedy S. J. Chilk, SECY H. H. Whitt.. side, SCNR Commissioner Gilinsky H. R. Myers, HCEE Transmitted:
HNBB.'l",3 PBldg).O7 SSBldgS'#[
L. V. Gossick, EDO E. G. Case, NRR C. V. Sidith, NMSS i
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H. Hanauer, EDO J. A. Harris, PA W. G. Mcdonald, MIPC Luge (MAIL)
E. Volgenau, IE [
Region #'#
R. G. Ryan, OSP T. J. McTiernan, 0IA
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H. K. Shapar, ELD i
PRELIMINARY NOTIFICATION
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