ML20247E684

Safety Evaluation Supporting Amend 119 to License DPR-61

ML20247E684
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	07/18/1989
From:	Office of Nuclear Reactor Regulation
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Shared Package
ML20247E670	List: ML20247E663 ML20247E678 ML20247E684
References
NUDOCS 8907260257
Download: ML20247E684 (4)

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UNITED STATES

[") }% NUCLEAR REGULATORY COMMISSION WASHING TON, D. C. 20555

%&.&);E SAFETY EVALUATION BY THE OFFICE,OF NL' CLEAR REACTOR REGULATION RELATED TO AMENDMENT, NO.119 TO FACILITY OPERATING LICENSE NO. DPR-61 CONNECTICUTYANKEEA10MIC_POWERCOMPANY HADDAM NECK PLANT DOCKET NO. 50-213 <

INTRODUCTION Pursuant to 10 CFR 50.90, Connecticut Yankee Atomic Power Company (CYAPCO) has proposed to amend the Operating License No. DPR-61 for the Haddam Neck Plant.  ;

By letter dated January 10, 1989, CYAPCO proposed to amend the Technical Specification (TS) sections that refer to the baron concentrations in idled and isolated loops. The amendment will: a) split and revise existing TS, Section 3.3.1.5 " Isolated Loop," into Sections 3.3.1.5 " Isolated Loop" (MODES I and 2) and 3.3.1.6 " Isolated Loop" (MODES 3, 4, 5 and 6), b) renumber and revise existing TS, Section 3.3.1.6 " Isolated Loop Startup," to TS Section 3.3.1.7 " Isolated Loop Startup," c) split and revise existing TS, Section 3.3.1.7 " Idled Loop," into Sections 3.3.1.8 " Idled Loop" (MODES I and 2) and 3.3.1.9 " Idled Loop" (MODES 3, 4, 5 and 6), and d) split and revise existing TS, Section 3.3.1.8 " Idled Loop Startup," into Sections 3.3.1.10 " Idled Loop Startup" (MODES 1 and 2) and 3.3.1.11 Idled Loop startup" (MODES 3, 4, 5 and 6). In MODES I and 2 the existing TS will remain unaltered. In MODES 3, 4, 5 and 6, the revised TS will require a boron concentration in the idled and isolated loops that is consistent with existing TS, Sections 3.1.10.2 ar,d 3.

DISCUSSION, The current TS's regTrding idled / isolated loops are designed to prevent reactivity transients due to intentional or unintentional startups of the idled / isolated loops. The current TS's require either the power to be removed from the isolation valve operators or the boron concentration in the idled / isolated loops to be maintained greater than or equal to the boron concentration in the operating loops. The proposed TS will not alter the existing TS while in MODES I and 2. However, in MODES 3, 4 and 5. the proposed TS will require that the bcron concentration in the idled / isolated loops be maintained such that the current shutdown margin requirements of existing TSs 3.10.1.2 and 3.10.1.3 are main-tained. In MODE 6. the idled / isolated loop will be required to be at no less than the refueling boron concentration as specified in existing TS Section 3.13.

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The amendment request is based on operational experience observed during the Cycle 15 startup. During the startup, the plant was maintained at a high baron concentration well above the minimum horon concentration required for shutdown margin con.;iderations. Eut due to bomn sampling accuraqy, a sample from the idled / isolated loop could deviate slightly from the operating loops and would require additional boration and sampling of the idled / isolated loop.

The licensee contended that the additional boration and rad waste generation was unneessary since the plant already exceeded the shutdown margin requirements. Therefore, the licensee proposed a revision to the TS requirements for MODES 3, 4 and 5.

EVALUKfl0H Existing TS 3.3.1.5, " Reactor Coolant System (RCS) - Isolated Loop" The existing section of the TS requires that the boron concentration in the isolated loop be maintained greater than or equal to the boron concentration in the operating loops while in MODES 1, 2, 3, 4, and 5. The proposed arandment divides this TS section into Sections 3.3.1.5 and 3.3.1.6. The new T5 Section 3.3.1.5, addresses the minimum boron concentration in the isolated loop while in MGDES I and 2. This remains unchanged from the current TS. Proposed TS Section 3.3.1.6 addresses the boron concentration while in MODES 3, 4, 5 and 6. The revised TS requires that the boron concentration be maintained greater than or equal to the amount required to meet the shutdown margin requirements as specified in the current TS Sections 3.10.1.2 and 3. In general, the shutdown margin requirement is based on the ability to mal.e the 4 reactor suberitical or prevent inadvertent criticality from a shutdown q condition. This requirement has been predetermined and specifically stated in existing TSs 3.10.1.2 and 3. By maintaining a boron concentration in the isolated loop such that the stated shutdown margin requirement is met, an intentional or unintentional loop startup will not result in a reactivity addition to the core and the reactor will remain subcritical. Therefore, the proposed TS changes will have no adverse istpact on reactor operation and the change will be consistent with the current safety analysis. TS Section 3.3.1.6 also requires that while in MODE 6, the isolated loop shall be at no less than the refueling boron concentration as stated in existing TS Section 3.13. This i is an additional requirement that will reduce the potential for reactivity transients dring MODE 6 operation and will ensure that the core will remain subtritical.

I Existing TS,Section 3.3.1.6, "RCS-Isolated Loop Startu__p" In the current TS, j lhis section requires that while in MODES 3, 4, 5 and 6, the loop shall remain isolated until: 1) the temperature at the cold leg of the isolated lonp is within 20 degrees F of the highest cold leg temperature of the operating loops, ,

2) the isolated loop boron concentration is greater than or equal to the boron l concentration of the operating loopt, and 3) the reacter is subtritical by at

! least 1000 percent millirho (pcm). The an.endment renumbers this section to x 3.3.1.7. In the revised TS Section the temperature requirements of the N i existing TS remain unchanged and thereby dL not alter the current safety }

I analysis. The amendment does revise the boron concentration requirements. The  :

revised requirements are that the isolated loop concentration be such that the 4

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I shutdown margin requirements of Sections 3.10.1.2 and 3 are maintained. In general, the shutdown margin requirement is bcsed on the ability to make the reactor subcritical or prevent inadvertent criticality from a snutdown condition. This requirement has been predetermined and stated in existing TSs 3.10.1.2 and 3. By maintaining a boron concentration in the isolated loop such that the stated shutdown margin requirement is met, a loop startup will not result in an unintentional reactivity addition to the core and the reacter will remain suberitical. Thus, the change will be consistent with the current safety analysis. Deleted from this section the stated requirement that the reactor must be subcritical by at leapt 1000 pcm. Since the definition of MODES 3, 4 and 5 require that K(eff)4.99 and MODE 6 requires K(eff)<.94, the '

reactor is already suberitical by at least 1000 pcm. As a result, the deletion has no effect on the Limiting Condition for Operation (LCO). There is an  ;

additional note in this TS which removes from the applicability section the '

instances when the hot leg loop isolation valve is opened to create an idled loop. This note was added to clarify the isciation to idled te operating loop startup sequence. Since the cold leg isolation valve is still closed in the idled loop configuration, there will be no flew induced reactivity insertion due to the temperature or boron concentration differences. Should the RCS be depressurized while in the idled loop configuration, the volume of water displaced from the idled loop into the remainder of the RCS would be minimal and its effect would be insignificant. Therefore, the added clarification has no adverse impact on reactor operation and plant safety.

ExM.N SecW.: 3.3.1.7, "RCS-Idled Loop" The existing TS requires that while in MOliT1' through 5, the borc. concentration in the idled loop be greater thtn or equal to the boron concentration in the operating loops. This l TS sr.ction has been divided into Sections 3.3.1.8 and 3.3.1.9 in the proposed amendment. The new Section 3.3.1.8 addresses the boron concentrations in the idled loop while in MODES 1 and 2 and remains unchanged fr

• the current TS.

Proposed TS Section 3.3.1.9 requires that the boron concer. ration in the idled bop, while in MODES 3, 4, and 5, be maintained greater than or equal to the concentration required to meet the shutdown margin requirements as specified in <

Sections 3.10.1.2 and 3. Following the analysis previously discussed in "RCS-Isolated Loop," by maintaining a boron concentration in the idled loop such that the stated shutdown requirement is met, an unintentional or  ;

intentional loop startup will not result in a reactivity addition to the core. l Therefore, there will be no adverse impact on reactor operation and the change l will be consistent with the current safety analysis. This TS section also I requires that while in MODE 6, the idled loop will be of no less than the  !

refueling boron concentration as stated in existing TS 3.13. This is an ,

I additional requirement which will reduce the potential for reactivity '

l transients daring MODE 6 operstion and will ensure that the core remains suberitical.  ;

Existing Section 3.3.1.8, "RCS-Idled Loop Startup" In the current TS, this section requires that in all MODE 5, the loop shall remain idled until: 1) the temperature at the cold leg of the isolated loop is within 20 degrees F of the highest cold leg temperature of the operating loops, 2) the isciated loop boron '

concentration is greater than or equal to the boron concentration of the operating loops, and 3) the reactor is no greater than 60% rated thermal power if one loop is idled or is subcritical by at least 1000 pcm if more than one loop is idled. This TS section has been divided into Sections 3.3.1.10 and 3.3.1.11. The new TS Section 3.3.1.10 addresses idled loop startup while in

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I MODES 1 and 2. Section 3.3.1.10 deletes the references to operation with more j than one loop idled. Since the plant does not operate in this configuration at i power, the deletion hes no effect on plant operation and safety. Otherwise, '

this section remains unchanged from the current TS. Section 3.3.1.11 addresses ,

idled loop startup in MODES 3, 4, 5 and 6. The temperature requirements cf 1 this section remain the same as the existing TS and thereby do not alter the  !

current safety analysis. The boron concentration has been changed such that, 1 the boron concentration in the idled loop will be maintained greater than or j equal to the boron concentration required to meet the shutdown margin requirements of existing TSs 3.10.1.2 and 3 (MODES 3, 4, 5) and 3.13 (MODE 6).

Following the analysis previously discussed for the isolated startup, by maintaining a boron concentration such that the stated shutdown margin requirement is met, a loop startup will not result in an unintentional reactivity addition to the core. TS section 3.3.1.11 also deletes the stated requirement that the reactor be subcritical by at least 1000 pcm and the requirement that the reactor be at no greater than 60% rated thermal power. As stated in the evaluation of existing TS section 3.3.1.6, by definition of MODES 3, 4, 5, and 6, the reactor is subcritical and the removal of these requirements does not remove any restrictions from the original TS.

In conclusion, the staff has determined that the TS changes will have no adverse impact on plant safety and will maintain the intent of the current TS while eliminating unnecessary operational difficulties. Therefore, the TS changes are acceptable.

ENVIRONMENTAL CONSIDERATION This amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. We have has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The staff has previously published a proposed finding that the amendment involves no significant hazards consideration and there has been no public coment on such finding. Accordingly, the amendment meets the eligibility criteria for categorica? exclusion set forth in 10 CFR %51.22(c)(9).

Pursuant to 10 CFR 951.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

CONCLUSION We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the ecmmon defense and security or to the health and safety of the public.

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Dated: July 18, 1989 Principal Contributor: G. E. Garten l

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