ML19275B600

Monthly Operating Rept for Feb 1976

ML19275B600
Person / Time
Site:	Oconee
Issue date:	03/09/1976
From:	Blakeman E DUKE POWER CO.
To:
Shared Package
ML19275B601	List: ML19275B600 ML19317E514 ML19317E519 ML19317E520
References
NUDOCS 7912180751
Download: ML19275B600 (3)

Text

..- .v . - u:tober 10, 1979

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P.'J.LI. h ev NOTIFIClTION OF EVENT OR UNUSUAL OCCURRENCE. PNO-II/79-1C Ibis oreliminary notific'ation constitutes EARLY notice of an event of POSSIBLE safety or oublic interest sunifica nce. The in. formation oresented is as initially received without verification or evaluation Ed is basically all that is known ey IE stafi as of this date FA.CILITY: Virginia Electric and Power Company North Anna Unit 1 '

Docket No. 50-338 Hineral, Virginia SUBJEti: REA C OR TRIP AND SAFETY INJECTION This supplements infomation previously submitted in PNO-IN79-13.

Region II (Atlanta) has cocpleted its investigation into the cause of the over-pressurization of the Volume Control Tank (VCT) and subsequent release of radio-active gases into the Auxiliary Building.

The i::vestigation determined that the control switch for the VCT level control system tas not defeated at the time of the incident. Overpressuri::ation of the VCI was caused by lif ting of the letdown line pressure relief valve, which Escharges to the VC, when letdown flow was automatically blocked due to a high level .n the Boron Recovery Syste= gas stripper. The high water level in the gas stripper was due to the high influx cf water from the primary system when 1:tdo a flow was reestablished. The investigation also determined that due to velu= of gas involved and the design of the radioactive waste handling syste.=,

the release of gas to the Auxiliary Building would not have been avoided or significa:tly lessened by proper connection of the vent line from the high level waste tanks. It appears that two ite=s of noncompliance occurred, both relating to syste: odifications without safety evaluations required by 10 CFR 50.59.

These acdifications involve the periodic defeating of the VCT level control valve during cperation and the vent line installatica. In the for=er case, no

.ide e of defeating other ccetrei switches was identified. Both of these

=atters zre being addressed in IE Circulars currently being prepared.

C.:tinued =edia interest is expected. Regica II does not plan to issue a pres release; however, the investigation report is receiving priority attenticc.

12 C.: ::vealth of Virginia is being i:ept infor=ed of developments.

- g o: ~1 (Atlanta) concluded its investigation at 5:00 p.a. on October 5, IE E

. t r. .: C. Alderson, RII 242-5507; P. J. Kellogg, RII 242-5649 0:.st-Outict: Trans=i".ted H. St.

..:::::n dendrie Cc=mtssioner Bradford S. J. Chilk, SICT

=is:dener Ker.nedy Cormusioner Ahearne C. C. Ks= erer, CA C: c-irci :er Gilinsky ACES (For Distributict; Tr:n::itted: ." N23  ?. Sidg. IE:XOOS (:E:EQ hst.

L. V, Gossick, EDO~ H. R. Denten, NRR

. L. Ornstein, EDO R. C. DeYoung, NRR J. J. Fouchard, PA R.'J. Mattson, NRR Landow (6 ein./page N. ". Haller, MPA D. Vassallo, NRR J . J . Cu==in g s , OI A R. G. Rvan, OSP D. Eisenhut, NRR E K. Shapar, ELD SS Bldg. MAIL W. J. Dircks, NMSS R. Minogue, SD Cther Regicnal Of fices S. Levine, RES II: ZOOS (Ti:te) 2 _3 ~

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