ML20083Q713

Final Part 21 & Final Deficiency Rept U-80 Re Failure of Containment Cooling Fans to Remain in Safeguards Position Following Safety Injection Signal Reset.Initially Reported on 840403.Mod Made to Cooling Fan Control Circuitry Design

ML20083Q713
Person / Time
Site:	Callaway
Issue date:	04/09/1984
From:	Schnell D UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
REF-PT21-84-255-000 IEB-80-06, IEB-80-6, PT21-84-255, PT21-84-255-000, U-80, ULNRC-795, NUDOCS 8404230208
Download: ML20083Q713 (2)

Text

l&~ So b/1)/)

l U NION ELECTRIC COM PANY 1908 GRATIOT STREET ST. Louis. MISSOURI meAsuNG ADDR.SSL oo=*;og,5cy~,.cc April 9, 1984. a * " '

,7 g , g ,,off,,,,,,

Mr. James G. Keppler Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road ULNRC- 79 5 Glen Ellyn, IL 60137

Dear Mr. Keppler:

FINAL 10CFR50. 55 (n)/PART 21 REPORT U-80 FAILURE OF THE CONTAINMENT COOLING FANS TO REMAIN IN SAFEGUARDS POSITION FOLLOWING SIS RESET

CALLAWAY PLANT On April 3, 1984 Union Electric informed the NRC Region III office of a deficiency reportable under 10CFR50.55 (e) . The deficiency involves the failure of the containment cooling fans to remain in low-speed (safeguards position) following the reset of a Safety Injection Signal (SIS). This problem was discovered during preoperational testing of the Engineered Safety Features Actuation System.

i The containment cooling fans normally operate in the high-speed position, and by design, should transfer automatically

! to low-speed during an SIS. The design basis is stated in the FSAR Chapter 6.2.2.2.2.3. In addition, NRC I.E. Bulletin #80-06 states that these fans should remain in that position when the SIS is reset.

The described problem was caused when the A/E, Bechtel Power Corporation, initiated a design change to allow speed control of the fans from the auxiliary shutdown panel after control room evacuation and isolation. This change inadvertently disabled the control scheme function that maintained the fans in slow speed following the reset of the SIS. This design oversight will be corrected with the addition of an interlock that will block the fans from returning to high-speed after the SIS is initiated. The fans will remain in slow speed until the operator acts to restore the fans to normal (fast speed). With this modification, the design of the containment cooling fan control circuitry will meet the' requirements stated in the FSAR and I.E.

Bulletin #80,-06.

h 0---

p ~pp" .

gpg 16 G84

- _ - _ _ _ _ _ . - _ _ _ _ - _ _ _ _ _ _ _ - _ _ _ - _ - - _ _ _ _ _ _ - - _ _ _ _ _ _ _ - _ - - _ _ - - - _ _ _M?

1 l

lo- '*

l l

1 This is our final report on this subject.

Very truly yours, 4

/

R Don ld F. Schnell GSA/RWF:glp cc: B. L. Forney, NRC Region III Richard DeYoung, Director I &E NRC Resident Inspectors, Callaway Plant (2)

Missouri Public Service Commission