ML20212M525

Submits More Accurate Description of 861204 Proposed Amends to Licenses DPR-39 & DPR-48 Re Reactor Containment Fan Coolers,Per Conversations W/Ja Norris.Revised Evaluation of Significant Hazards Consideration Encl

ML20212M525
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	03/03/1987
From:	Leblond P COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
2733K, NUDOCS 8703120058
Download: ML20212M525 (6)

Text

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/g1 Conunonweehh Edson

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___ ' One Fwst Nabonel Plaza, Cheago, Ihnois

" l Address Reply to: Poet Omco Box 767

• Cheago, Ihnois 60600 - 0767 March 3, 1987 Mr. Harold R. Denton

-U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC. 20555

Subject:

' Zion Nuclear Power Station Units 1 & 2 Proposed Amendment to Facility Operating

. License Nos. DPR-39 and DPR-48 Reactor Containment Fan Coolers NRC Docket Nos. 50-295 and 50-304

Reference:

December 4, 1986 letter from P.C. LeBlond to H.R. Denton.

Dear Mr. Denton:

The referenced letter transmitted a proposed amendment to Facility Operating License Nos. DPR-39 and DPR-48, Appendix A, Sections 3.5 and 4.5 -

Reactor Contain:nent Fan Coolers. That proposed amendment clarifies these sections following a recent modification to the reactor containment fan coolers (RCFC). Subsequent conversations with Mr. J.A. Norris of your staff has resulted in the need to more accurately describe this modification. This description will also form the basis for a revised significant hazards consideration in support of the proposed amendment.

In 1984, the heat exchangers for Zion's 10 RCFC's were exhibiting degradation of the service water cooling coil tubing. This tubing had degraded to the extent that through-wall holes had developed and leakage b']

occurred. The RCFCs design function is to remove heat from the containment

, atmosphere and transfer it to the service water system under both normal and accident conditions. The plugging of leaking coil tubes was compromising this function. Therefore, a modification was planned to replace the existing RCFC service water cooling coils with new coils of a design that would minimize the degradation phenomenon.

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Mr..H. R. Denton >

-2; March 3, 1987 This replacement activity also was intended to upgrade the. heat removal capability.of.the RCPC's by increasing both the heat transfer capabilities'of the coil.and the air flow rate. Associated with this effort-was a goal to simplify the operation of the RCPC's. The simplification of the RCPC by the elimination of the " normal" air path would result in. increased reliability.

The need for'the two existing modes'of operation,' normal and accident, was reviewed as part of this effort. The results of this review demonstrated that the PSAR did not take any credit for any effects of containment cleanup from the existing moisture separators and HEPA filters. ' Thus, the existence of two separate air flow paths, and the resultant need-to actuate the accident mode, was superfluous.

The resulting RCPC modification had the following elements.

- Replacement of the RCPC heat exchanger

- Removal of the moisture separators

- Removal of the HEPA filters Air control dampers permanently placed in the accident mode Technical Specification 4.5.1.A.3 states: Each "

fan cooler damper shall be stroked to the accident position and the position indication checked during each refueling outage." In addition, the basis for this section states; "The testing program is adequate to ensure continued availability of each'of the-fan coolers. It will further provide assurance of the continued operability of those fan cooler components used only during an accident situation."

Thus, the intent of the RCPC refueling surveillance is to ensure that the accidant airflow path is'available. A simple verification that the dampers remain in the accident position satisfies the surveillance requirements.

Therefore, the placement of the control dampers in the accident position does not preclude the performance of the surveillance requirements of Section 4.5.

The attachment to this letter contains a revised demonctration that the proposed amendment contained in the referenced letter does not involve a  ;

signficant hazards consideration. Please replace Attachment 2 of the referenced letter with this information.

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Mr. H. R. Denton March 3, 1987 l

l If you have any further questions regarding this matter, please 1 direct them to this office.

I very truly yours, j l

P. C. LeBlond Nuclear Licensing Administrator 1m Attachment 4

cc: Resident Inspector-Zion '

J. A. Norris-NRR M. C. Parker-State of Ill.

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,4 ATT N EVALUATION OF SIGNIFICANT H.m me CONSIDERATION 4 ,

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PROPOSED CHANGES TO ZION TECHNICAL SPECIFICATION APPENDIX A - SECTIONS 3.5 and 4.5 REACTOR CONTAIMENT FAN COOLERS ,

DESCRIPTION OF Ariwiuri6r!T REQUEST

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An amendment to the Zion Facility Operating License is proposed to clarify the surveillance requirements, requiring Zion's Station RCFCC and to convert these section's format'.to the Standardized Technical Specification-format. ,

i3CKGROUND 10 CFR 50.92 states that a proposed amendment will involve a no significant hazards consideration if the proposed amendment does not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or

! (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

In addition, the Comnission has provided guidance in the practical application of these criteria by publishing eight examples in 48 FR 148*10.

The discussion below addresses each of these three criteria and t demonstrates that the proposed amendment involves a no significant hazards consideration.

BASIS FOR NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION Does the proposed amendment (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or l'

(2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety?

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DISCUSSION - ITEM #1 The proposed change, and the ur.derlying modifications, have no effect on the operation of Zion's RCFCs. The physical modification has not affected-the availability of tne accident air flow path during accident conditions.

Rather,-the physical modification has resulted in the accident flow path being-continuously available and increased heat removal capacity. Thus, the RCFCs-are always available to perform their safety function.

Chapter 14 of the Zion FSAR assumes that'three RCFCs are operating'in the post-LOCA containment-environment to remove energy from the containment atmosphere.. The ability of Zion's RCFCs to perform this function has been increased as a result of this physical modification. The heat removal capability has been increased-and the need to automatically transfer from the normal to the accident air flow path has been eliminated. Thus, the RCFCs-ability to perform their designed function has not degraded.

The modification of the verb " stroke" to the verb " verify" merely clarifies the intent of the existing surveillance to ensure that the accident flow path is continuously available. The existing Technical Specification surveillance requires that the dampers be stroked and verified in their accident positions every refueling. There is no requirement to stroke the dampers back to the normal flowpath position. Thus, the modification of the verb " stroke" to the verb " verify" merely formalizes the preexisting intent of the Zion Technical Specifications.

Based upon the above discussion, this 'roposed amendment does not

. involve a significant increase in the probab) . er or consequences of any 4 accident previously evaluated.

DISCUSSION - ITEM #2 The clarification of the existing intent of the Zion Technical ,

specifications and the alteration of the format of Section 3.5 and 4.5 has no effect on any of Zion's systems or structures. As discussed above, the RCFCs heat removal capability and reliability has been increased. These improvements do not result in any additional system interactions. Thus, there can be no

-potential for any previously unanalyzed malfunction or component failure.

f The RCFCs are intended to remove energy from inside of the j containment structure following a main steam line break or a loss of coolant accident. The analyses for these accidents contained in Zion's FSAR have been reviewed. Based upon the lack of system interaction discussed above, the proposed clarification of the Zion Technical Specifications, and the underlying physical modification, will not affect any of the pre-existing accident i sequences.

Thus this proposed amendment does not create the possibility of a new l or different kind of accident from those previously evaluated-f

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4 DISCUSSION - ITEM #3 The RCFCs will remain continuously available to perform their intended safety function. The physical modifications to the RCFCs have resulted in more efficient and reliable operation. 'Thus, the margin of safety has been increased as a result of the physical RCFC modification.

However, the proposed amendment only involves.the clarification and reformatting of the Zion Technical Specifications which does not affect the safety function of the RCFCs. Since the RCFCs ability to remove energy from inside of the Zion containment structure will be unaltered by this administra-tive clarification, there will be no change in the margin of safety due to the proposed Technical Specification amendment.

This proposed change involves clarifying the existing intent and reformatting of' Sections 3.5 and 4.5 of the existing Zion Technical Specifications. Thus, example (i) is applicable in this instance. Example (i) reads as follows:

(i) A purely administrative change to technical specifications: for example,.a change to achieve consistency throughout the l

technical' specifications, correction of an error, or a change in.

nomenclature.

Therefore, since the application for amendment satisfies the criteria specified in 10 CPR 50.92 and is similar to examples for which no significant hazards consideration exists, Commonwealth Edison Company has mide a determina-tion that the application involves no significant hazards consideration.

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