ML20215A638

Safety Evaluation Re Bases to Tech Spec 2.4, Containment Cooling. Proposed Changes to Bases for Section 2.4 Serves to Editorially Change Error,Make Phrases & Statements More Accurate & Reflect Current Terminology

ML20215A638
Person / Time
Site:	Fort Calhoun
Issue date:	06/10/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20215A631	List: ML20215A628 ML20215A638
References
TAC-65057, NUDOCS 8706170011
Download: ML20215A638 (4)

Text

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,v a cvg'o, UNITED STATES j 4

[e .g f) NUCLEAR REGULATORY COMMISSION

• WASHINGTON. D. C. 20555 g .t

\...../ SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i

BASES TO TECHNICAL SPECIFICATION 2.4, "CONTAINHENT COOLING" FORT CALHOUN STATION, UNIT NO. 1 DOCKET NO. 50-285 l

1.0 EVALUATION In a letter dated March 26, 1987, Omaha Public Power District (licensee) requested editorial changes in the Technical Specification Bases relating to containment cooling. The proposed changes to the Bases for Section 2.4 serves to editorially change an error, make phrases and statements )

more accurate, and reflect current terminology. (

2.0 EVALUATION f A Safety Systems Outage Modification Inspection Team conducted inspections in late 1985 and early 1986. Among the findings of the team was an  ;

apparent typographical error in the Bases to Technical Specification 2.4.  !

The Bases of the Technical Specification has remained in its current state  ;

since the original issue of the operating license. l The statement to be changed currently reads, "Three component cooling j waterheatexchgngershavesufficientcapacity(withamplereserve)to remove 402 x 10 Btu /hr following a loss-of-coolant accident." The Updated Safety Analysis Report (USAR), Section 9.7.5 (consistent with the FinalSafetyAnalysisReport(FSAR)),speciffestheaccidentcapacityof a component water 6 heat exchanger as 134 x 10 Btu /hr, resulting in a total of 402 x 10 Btu /hr for three component cooling water heat exchangers.

The phrase regarding "with ample reserve" has been removed. " Ample" is a subjective term; and information in the Technical Specifications is definitive, whereas "with ample capacity" is not.

In addition, the statement, "the component cooling water system equipment ,

is accessible for the repair after a loss-of-coolant accident," has been removed from the Bases. Radiation studies done after the incident at Three Mile Island indicates that this statement may be somewhat misleading. <

Further, the Bases to Technical Specifications should be founded in fact rather than sweeping generalizations. For this reason, the licensee purposes to delete this statement: Also, the fact is that removing this statement has no impact on the specification.

Finally, the reference to "FSAR" in Section 2.4 have been reworded to i "USAR". This change is simply in keeping with the current terminology. f 1

8706170011 870610 PDR ADOCK 0500{ S P

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3. 0. CONCLOSION-J Based on our review, we' concur with the licensee that the proposed changes are ' editorially in nature to the Bases for Technical Specifica-tions, Section 2.4, and is appropriate and necessary to clarify the Bases. t Principal Contributor:

-A. Bournia Dated:

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2.0 LIMITING CONDITIONS FOR OPERATION I 2.4 Containment Cooling (Continued) J component cooling heat exchangers and shutdown heat exchangers. A full-capacity diesel generator is connected to each of the two engineered safeguards 4.16-kV buses. Three engineered safeguards 480-Volt double- I ended load centers are provided; of the six transformers, three are  !

connected to each of the two 4.16-kV buses. Two load centers are operated as two-bus-section units; the third is provided with a center i bus manually transferable to either associated end section. The center i bus section supplies HPSI Pump SI-2C, CS Pump SI-3C and Charging Pump CH-1C any of which can thus be supplied from either 4.16-kV bus if required. Three component gooling heat exchangers have sufficient l

capacity g remove 402 x 10 BTU /hr following a loss-of-coolant accident. The containment sprays initially take coolant from the safety injection and refueling water (SIRW) Before this supply ofwaterisexhausted(atleast24 minutes)gnk. the spray system is transferred to the recirculation mode and the pumps take suction from the containment sump. One shutdown cooling heat exchanger is sufficient to satisfy the g ay system requirements during the long-term containment cooling period. In addition, in the unlikely event of the component cooling water supply being lost, raw water can be utilized for direct cooling of the shutdown heat exchangers and containment cooling coils.(4)

The containment spray system is redundant with the containment air recirculation, cogng and iodine removal system for the containment cooling function. The spray system is sized such that two of the three spray pumps would limit the containment pressure to below the design value following a DBA without taking credit for g air coolers or the cooling capacity of the safety injection system. Similarly, two cooling and filtering units or one cooling and filtering unit and bothcoolingunitshavethecapabilityoflimitingthegntainment pressure under the same conditions as two spray pumps.

The redundant cooling equipment provided to limit the containment pressure following a DBA is divided between the independent power supply systems. The raw water and component cooling water pumps are similarly distributed on the 4.16-kV and 480 Volt buses to serve the above cooling groups. Each cooling group has a design capacity equal to that required to restrict the containment pressure to below the design value. In the event of a DBA, loss of normal power sources and failure of one diesel-generator to operate, better than one full group would be connected to the available diesel generator, thus providing more than ample reserve. Any one unit removed from a given bus does not restrict the groups which can be connected to one diesel-generator l from fulfilling their design function. The removal of two units from buses which can be connected to one diesel generator could limit the capability of the associated cooling groups; therefore, to ensure availability of the power supply to che redundant equipment in the event of loss of normal power sources, the diesel-generator serving this redundant equipment is started to demonstrate operability. During 1

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2-26 Ltr dated:

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2.0 LIMITING CONDITION FOR OPERATION I2.4 ' Containment Cooling (Continued) .

I normal power operation either two air cooling and filtering units or {

two air; cooling units and one air cooling and filtering unit are in operationto(gmoveheatlostfrompipingandequipmentwithinthe f containment. In' addition, if during the post-accident phase the component cooling water supply is lost, containment cooling could be

• maintained until repairs are effected. The component cooling system pumps and heat exchanger,-the spray pumpu and t

. changers are located in the auxiliary building.gg)sgownThe heat rawex-- l water pumps are located in the intake structure.(33)

References (1)' USAR, Section 9.7.5 .

(2) USAR, Section 6.2.3.1 (3) 'USAR, Section 6.2.3.4 (4) USAR, Section 9.8.2 (5) USAR, Section 6.4.5 .

(6) USAR, Section 6.3.5 (7) USAR, Section l'4.16.5 (8) USAR, Section 9.10.2.3 (9) USAR, Section 9.7 I (10) USAR, Section 6.3 l (11) USAR, Section 9.8 l

i 2-27 Ltr dated:

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