ML20027A406

Safety Eval Supporting Amend 27 to Facil Oper Lic DPR-2. Concludes There Is No Increased Risk from Its Implementation

ML20027A406
Person / Time
Site:	Dresden
Issue date:	11/09/1978
From:	Office of Nuclear Reactor Regulation
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ML20027A407	List: ML20027A406
References
NUDOCS 7811270078
Download: ML20027A406 (4)

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8 UNITED STATES b

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NUCLEAR REGULATORY COMMISSION h

n,./ls, ev,e W ASHINGTON, 0. C. 20555 i

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 27 TO FACILITY OPERATING LICENSE NO. OpR-2 COMMONWEALTH EDIS W COMPANY DRESDEN UNIT NO. 1 DOCKET NO. 50-10 Introduction By letter dated September 11, 1978, the Commonwealth Edison Company (CECu) requested an amendment to Facility Operating License No. DPR-2 for the Dresden Station Unit No.1.

The requested changes would permit nonpower operation of the reactor beyond October 31,.1978, for the purpose of performing a control blade test.

The test would measure the effect of boron depletion (burnout of neutron absorbing boron atoms) in the Dresden Unit 1 control blades.

The results of these tests would assure that safety margins associated with control blade negative-reactivity are not degraded by boron depletion.

Background

The Dresden Unit 1 Facility Operating License currently restricts reactor operation beyond October 31, 1978 unless plant modifications ordered by the NRC are completed.

These modifications include:

l 1.

The installation of a High Pressure Cooling System and redundant l'

sources of onsite auxiliary a.c. power,

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2.

Modification of the plant design to make the plant protection l-system conform with the requirements of Sections 4.2 " Single Failure Criterion" and 4.6 " Channel Independence" of IEEE Standard 279-1968, 3.

The installation of fixed automatic fire protection system at l

the sphere electrical penetrations and in the cable tunnel connecting the sphere to the control room complex, and 4

An extensive qualification program of installed equipment and the subsequent replacing or relocating of those components found to be not qualified for their intended functions in the l

postulated environments.

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l 781127:c 73

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. i These modifications are under way and will be completed prior to returning-Dresden Station Unit I to power operation following the decontamination outage 1

that began on October 31, 1978.

Evaluation The Control Blade fleasurement Test proposed by CECO involves the following steps:

1.

The reactor would be made critical using the depleted control bl ade.

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2.

Reactor period, moderator temperature, and control rod positions would be recorded.

3.

The reactor would be shutdown and the depleted control rod replaced with a new un-irradiated control rod.

4.

Steps 1 and 2 would be repeated maintaining the same. moderator temperature and control rod pattern.

5.

The magnitude of the boron depletion would be determined by comparing the reactor period obtained under identical reactor conditions using a depleted control rod and a new un-irradiated control rod.

Our evaluation of each of the requested changes follows:

1.

Paragrapn 2. C. (3 )

CECO. requests that the words "except for the purpose of low power physics tests conducted prior to nidnight on 12/31/78" be added to the license condition that prohibits operation i

beyond October 31, 1978, unless the modifications related to the IEEE-279 order, the fire protection nodification to the cable tunnel, and the environmental qualification of equipment are complete.

We have reviewed the requested change and have determined that the change conforms to the staff's intent that reactor power operation should cease as soon as the work on the reactor modifications can begin.

Because these nodifications are not needed for low power pF.ysics tests which are conducted at less than 4"; reactor power with the reactor at atmospheric pressure and the vessel head removed the staff concludes that this change is acceptable.

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2.

Paragraph 2.C. (4). (4)

The staff has concluded that the Energency Core Cooling System, ECCS, is not required during the low power physic testing because the reactor would be at less than 4% licensed power and depressurized with the vessel head removed.

Because the ECCS is not needed, the staff has concluded that the addition of the words "Except for the purpose of low power physics tests conducted' prior to midnight on 12/31/78" is _ accepta bl e and that such operation is permitted by the current Technical Specifications and does not involve an unreviewed safety question.

4 3.

Paragraphs 2.C.(5)(4), 2.C.(5)(5) and 2.C.(6)

CECO requested that the above license conditions be modified to delete the requirements for:

(1) the interim core spray connection to the fire system, (2) the back up diesel generator-to be operable, and (3) the surveillance requirements on the l

back up diesel generator.

We have determined that these systems and surveillance require-ments are not needed during the low power physics tests with the vessel depressurized and the requested deletion will not reduce the margin of safety for. operation below 4% of rated power.

On this basis, we have concluded that deletion of these specifications is acceptable.

Environmental Consideration I

We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint or environmental impact and pursuant to 10 CFR 551.5(d)(4) that an environ-mental impact statement, or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.

i Conclusion i

We have concluded, based on the considerations discussed above, that:

l (1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment

. does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, und (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.

Da te : flovember 9,1978 I

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