ML20006F346

Proposed Tech Specs Re Limiting Conditions for Operation for Steam & Feedwater Sys

ML20006F346
Person / Time
Site:	Fort Calhoun
Issue date:	02/21/1990
From:	OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20006F297	List: ML20006F296 ML20006F298 ML20006F346
References
NUDOCS 9002270420
Download: ML20006F346 (7)

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2.0 LIMITING CONDITIONS FOR OPERATION

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2.5 Steam and Feedwater Systems  !

Aeolicability .

Applies to the operating status of the steam and feedwater systems.

Ob.iective To define certain conditions for the steam and feedwater system necessary '

to assure adequate decay heat removal.

Specifications  !

I The reactor coolant shall not be heated above 300'F unless the following l conditions are met:

(1) The motor driven auxiliary feedwater pump is operable. The  !

reactor shall not be made critical unless the steam driven  ;

auxiliary feedwater pump is operable. During modes 1 and 2, i one auxiliary feedwater pump may be inoperable for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, provided that the redundant component shall be tested to -

deinonstrate operability. l (2) A minimum of 55,000 gallons of water in the emergency feedwater i storage tank and a backup water supply to the emergency feedwater storage tank from the Missouri River by the fire water system shall be available. l (3) All valves, interlocks and piping associated with the above  :

components required to function during accident conditions are operable. Manual valves that could interrupt auxiliary feedwater flow to the steam generators shall be locked in the  ;

required position to ensure a flow path to the steam '

generators.

(4) The main steam stop valves are operable and capable of closing in four seconds or less under no-flow conditions.

S.Aih A reactor shutdown from power requires a removal of core decay heat. t Immediate decay heat removal requirements are normally satisfied by  ;

the steam bypass to the condenser. Therefore, core decay heat can be

• continuously dissipated via the steam bypass to the condenser as long as feedwater to the steam generator is available. Normally, the capability to supply feedwater to the steam generators is provided by I operation of the turbine cycle feedwater system. In the unlikely event of complete loss of electrical power to the station, decay heat removal is by steam discharge to the atmosphere via the main steam safety and atmospheric dump valves. Either auxiliary feedwater pump 2-28 Amendment No. #

9002270420 900222 PDR ADOCK 05000285 N

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i 2.0, LIMITING CONDITIONS FOR OPERATION l

2.5 Steam and Feedwater Systems can supply sufficient feedwater for removal of decay heat from the plant. The minimum amount of water in the emergency feedwater storage tank is the amount needed for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of such operation.

be re-supplied with water from the fire protection system.Jgy tank can 3 A closure time of 4 seconds for the main steam stop valves is I considered adequate time and was selected as being consistent with expectedresponsetiyg)igyinstrumentationasdetailedinthesteam line break analysis.  ;

References (1) USAR, Section 9.4.6 l (2) USAR, Section 10.3 l (3) USAR, Section 14.12 l 2-29 Amendment No, f) l l

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ATTACHMENT B 4

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. Discussion Justification and No Significant Hazards Consi.ieration The proposed changes to Technical Specification Section 2.5, Page 2 28, and Page 2-29 are requested to allow performance of a functional test of the steam driven Auxiliary Feedwater (AFW) Pump (FW-10) prior to achieving criticality and to correct administrative and a typographical errors. The present temperature of 300*F will not provide enough steam to allow for a normal operability test.

The design basis of the AFW system is to remove decay heat after a reactor shutdown from power operation in the unlikely event of a complete loss of electrical power to the station. In addition, either Auxiliary Feedwater Pump can provide sufficient feedwater for removal of decay heat.

The current Technical Specifications allow either auxiliary feedwater pump to be inoperable for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after going above 300'F. In theory this would allow enough time for the plant to heat-up to the point that a normal operability test of the steam driven pump could be run. Typically, however, due to steam generator soaks the period it takes to heat up the plant so that this test can be run is greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This issue has been solved at one other plant (see References 2 and 3) by requiring that the steam driven pump be operable

")rior to making the reactor critical." This allows heat up of the plant to tie point where steam can be produced to perform a normal operability test using non-nuclear heat.

No Significant Hazards Consideration l This proposed amendment does not involve a significant hazards consideration because the operation of Fort Calhoun Station in accordance with this amendment would not:

1. Involve a significant increase in the probability or consequences of .

an accident previously evaluated. Accidents have been analyzed I assuming the auxiliary feedwater system is available to provide l removal of decay heat produced during the eight hours after a reactor i trip concurrent with a loss of main feedwater. The current specifi-cation allows either the electric or steam-driven auxiliary feedwater pump to be inoperable when the reactor coolant temperature is above i 300*F for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The proposed change would require the motor driven pump be operable above 300'F with the reactor subcritical when the steam driven pump would be of little use due to the lack of steam and decay heat.

2. Create the possibility of a new or different kind of accident. from any I previously evaluated. The proposed change does not physically alter i the configuration of the plant and no new or different mode of opera-tion has been implemented. Therefore, the possibility of an accident or malfunction of a new or different type than any previously evaluated in the safety analysis report is not created.

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3 Involve a significant reduction in a margin of safety. Decay heat removal 11s still assured to the same degree as prior to this change

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3 because the operability requirements of the Auxiliary Feedwater System have been clarified and strengthened. The intent of the specification has not been changed, and inus the basis for the safety analysis is -

1 maintained. As a result the margin of safety is not reduced. .

Therefore, based on the above consideration Omaha Public Power District has determined that the change does not involve a significant hazards consideration. .

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