ML17252A982

Letter Reporting a 04/19/1973 Occurrence Related to Secondary Containment Not Being in Effect for Approximately Six Hours - Dresden Units 2 and 3

ML17252A982
Person / Time
Site:	Dresden
Issue date:	04/27/1973
From:	Worden W Commonwealth Edison Co
To:	Giambusso A US Atomic Energy Commission (AEC)
References
WPW Ltr. #337-73
Download: ML17252A982 (2)

Text

50-237 R9glllifory 50-249 Commonwealth~. Edison Company 0 NE FI~ ST NAT I 0 NA L PLAZA

• CH IC AG 0, ILL I NO IS WPW Ltr. f/337-73 Mr. A. Giambusso Deputy Director for Reactor Projects Directorate of Licensing I.

U. s. Atomic Energy Commission Washington, D.C. 20545

SUBJECT:

LICENSE DPR-19 AND DPR-25, DRESDEN NUCLEAR POWER STATION, UNITS

1. 2 AND 3, SECTION 6.6.B.3 OF THE TECHNICAL SPECIFICATIONS.

Dear Mr. Giambusso:

This is to report a condition relating to the station in which on April 19, 1973, secondary containment integrity was not in effect for a period of ap.proximate~y six hours, contrary to Technical Specifications Section 3. 7. C.

PROBLEM AND INVESTIGATION At approximately 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on April 19, 1973, unit 3 :mSin steam isolation valve (MSIV) 3-203-2B was disassembled for an inspection of the valve internals during a maintenance outage. Since the unit 3 turbine stop valves were also disassembled for inspection, opening valve 3-203.-2B established a direct flow path from the turbine building into the turbine.steam chest through main steam line 3-3001B-24" into the main steam line tunnel, which is part of unit 2/3 secondary containment *.

The investigation revealed a turbine bypass valve and two high pressure turbine Steam lines were open to the turbine building. The bypass valve flange was replaced at approximately 1730. Since the turbine steam inlet lines could not be reinstalled rapidly, a blind flange was installed on MSIV 3-203-2B.

Sec~~d~ry containment is required at all times that primary contain-ment is required as well *as* during refueling.* *-.During the short period of time secondary containment 'Was broken, unit 113 reactor was in the refuel mode with local power range monitor (LPRM) replacement and fuel moves in progress and

. unit #2 was operating at near rated power *

~831?.

The loss of secondary contairunent for this short period of time did

• not-*resiJlt in a "ground level release since the air flow. w,as: j.~Jo. the secondary containment from the turbine building.* Had an event occurred which resulted in release of radioactivity to the secondary contaimnent and had the air flow direction been reversed, a release path would have existed .from the secondary containment to the turbine building.

CORRE.CTIVE ACTION A blind flange was installedon'MSIV 3-203-2B at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> and secondary *containment was restored. A change wql be made in the "Request for Equipment Out of Service" form to include a "Secondary Containment Integrity

• Ef*fected" *Check *space. This change ,s*houl;d -be *comp'l:eted* -by Jurie 1,

• 1'973.

Sincerel:r;

\.D 'Q. . \.Lt"'-&lG W. P. Worden Superintendent WPW:RC:jw cc: . WPW Ltr. File

'2830*