ML20053E995

Ro:On 820519,potential Failure of Turbine Driven Auxiliary Feedwater Pump Steam Supply Line Identified.Condition Not Considered in Sar.Design Mod Being Evaluated

ML20053E995
Person / Time
Site:	Fort Calhoun
Issue date:	05/20/1982
From:	William Jones OMAHA PUBLIC POWER DISTRICT
To:	Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20053E993	List: ML20053E995
References
LIC-82-210, NUDOCS 8206100278
Download: ML20053E995 (2)

Text

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Omaha Public Power District 1623 HARNEY e OM AH A. NEBRA&MA 65102 e TELEPHONE S36 4000 AREA CODE 402

.. May 20, 1982 LIC-82-210 Mr. W. C. Seidle, Chief Reactor Project Branch 2 U. S. Nuclear Regulatory Comission Region IV -

611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011

Reference:

Docket No. 50-285

Dear Mr. Seidle:

Potential Failure of Turbine Driven Auxiliary Feedwater Pump Steam Supply Line In accordance with the Fort Calhoun Station Technical Specifications, the District informed Mr. John Jaudon of your office of a potential concern identified during the District's review of INP0 SOER 81-17.

This letter is to provide confirmation of that notice, which was made on May 19, 1982 by telephone.

In reviewing INP0 SOER 81-17, the District identified a condition not specifically considered in the Fort Calhoun Station Safety Analysis Report. This condition involves the unlikely event of a significant release of steam into Room 19, which Fouses both the steam driven and motor driven auxiliary feedwater pumps, FW-10 and FW-6 respectively. A single failure in the steam supply line of FW-10 could potentially sr1 ject FW-6 to an environment in which it is not qualified to operate.

Actions which have been taken or will be taken by the District to pre-vent the development of such a steam release are detailed below. The design of this portion of the auxiliary feedwater system is being evaluated in order to identify design changes which will prevent the consequences of a significant steam release in this room from affecting the proper operation of auxiliary feedwater pump FW-6. The exact nature of these changes has not been determined; however, the design and pro-curement process will be expedited so thtt the installation can proceed during the next cold shutdown of sufficient duration after receipt of the materials or sooner, if an outage is not needed for implementing the design change.

The following interim corrective actions were taken on May 19, 1982.

FW-10's steam system was i~ Jected for leaks during a special run of the pump surveillance test. '. 5 ins'pection included the two inch supply line, the supply valve upstream of the turbine, and the FW-10 turbine itself. No leaks were identified. This test and inspection will be perfonned monthly rather then quarterly and after any maintenance outage of the FW-10 steam system, until the modification is completed.

8206100278 820603 PDR ADOCK 05000285 g PDR

' Mr. 'W. C. Seidle LIC-82-210 Page Two ,

Further, special instructions to operators have been issued, making them aware of the steam release concerns and requiring the following actions:

(1) Provide preferential operation of FW-6. Following initiation of the feedwater system, the operators will verify auxiliary feedwater flow to the steam generators, operation of FW-6, and shut down FW-10. This reduces operating time of FW-10.

(2) During operation of FW-10, the operator shall monitor Room 19 for potential steam conditions using the fire detection system alarms and security system television monitor. The fire detection ionization instruments located in this room will sense any significant release of steam which would actuate the fire system annunciation circuits, thes alerting the oper-a tors.

(3) Should a steam release be verified, the operator will isolate FW-10 from the control room or, if necessary, manually at the steam isolation valves located in Room 81 which is within a few seconds walk of the control room.

The likelihood of a significant steam leak developing undetected is reduced by the increased frequency of testing and special inspections.

In addition, t' en FW-10 steam supply line is maintained in a heated condition, thereby reducing thermal cycling of the system and reducing the probability of developing a leak. The constant steam pressure maintained in this line will also aid in detection of piping leaks during routine tours of the auxiliary building by operators. It should also be noted that the probability of FW-6 End FW-10 initiation due to loss of offsite estimated at 10 gower using and thesubsequent WASH-1400FW-10 steam supply pipe rupture is data base.

Based upon the interim measures initiated and the very low probability of such an event occurring, the District believes that there is adequate assurance that the steam release event in Room 19 does not pose a threat to public safety and contineed operation of the Fort Calhoun Station is justified. Additionally, the District will continue to expedite the development of a permanent resolution to this concern.

Sincerely,

-n

/ 5^^

W. C. / pones Division Manager Production Operations cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.

Washington, D.C. 20036

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