1CAN068602, Rev to 860117 Application for Amend to License DPR-51, Providing Addl Info Re Description of Amend Request & Basis for NSHC Concerning Increasing Low RCS Pressure Engineered Safeguards Actuation Sys Initiation Setpoint

Rev to 860117 Application for Amend to License DPR-51, Providing Addl Info Re Description of Amend Request & Basis for NSHC Concerning Increasing Low RCS Pressure Engineered Safeguards Actuation Sys Initiation Setpoint

ML20206S199
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/24/1986
From:	Tison Campbell ARKANSAS POWER & LIGHT CO.
To:	Stolz J Office of Nuclear Reactor Regulation
Shared Package
ML20206S204	List: 1CAN068602, Rev to 860117 Application for Amend to License DPR-51, Providing Addl Info Re Description of Amend Request & Basis for NSHC Concerning Increasing Low RCS Pressure Engineered Safeguards Actuation Sys Initiation Setpoint ML20206S217
References
1CAN068602, 1CAN68602, NUDOCS 8607070307
Download: ML20206S199 (5)

Text

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lh l l;3 ARKANSAS POWER & LIGHT COMPANY FIRST COMMERCIAL BUILDING /PO. BOX 551/LITTLE ROCK. ARKANSAS 72203/(501) 371-7901 June 24, 1986 T. GENE CAMPBELL Vice President Nuclear Operations 1CAN068602 Mr. John F. Stolz, Director PWR Project Directorate No. 6 Division of PWR Licensing - B U. S. Nuclear Regulatory Commission Washington, DC 20555

SUBJECT:

Arkansas Nuclear One - Unit 1 l Docket No. 50-313 l License No. DPR-51 l Proposed Technical Specification for ESAS l Low RCS Pressure Setpoint -

Additional Information

Dear Mr. Stolz:

Our letter dated January 17, 1986 (lCAN018602) provided a proposed technical specification amendment for increasing the Low RCS Pressure ESAS Initiation setpoint. Since that time we have had several discussions with Mr. Guy Vissing concerning the amendment and have been requested to provide additional information. i l

The concerns relate to the " Description of Amendment Request" and the " Basis for No Significant Hazards Consideration." Consequently, we are submitting revisions to these portions of the previous submittals. The Technical Specification change pages are not affected; however, we are resubmitting them for completeness.

In accordance with 10CFR50.92(c), we have determined the proposed amendment to involve no Significant Hazards Consideration (SHC) and are including the basis of our SHC determination as an attachment to the proposed change.

Also a copy of this amendment package is being forwarded to Mr. E. Frank Wilson, Director, Division of Environmental Health, State of Arkansas.

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. The application fee, pursuant to 10CFR170.12(c), was provided with our i January 17, 1986 submittal.

4 Very truly yours, 1 / W a T. Gene Campbell TGC/JTE/CHT/sg Attachments 4

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STATE OF ARKANSAS )

) SS COUNTY OF PULASKI )

I, T. Gene Campbell, being duly sworn, subscribe to and say that I am Vice President for Arkansas Power & Light Company; that I have full authority to execute this oath; that I have read the document numbered 1CAN068602 and know the contents thereof; and that to the best of my knowledge, information and belief the statements in it are true.

WWM /

T. Gene Campbell r

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SUBSCRIBED AND SWORN TO before me, a Notary Public in and for the County and State above named, this c) 5 day of bu ,

1986.

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DESCRIPTION OF AMENDMENT REQUEST The current technical specification low RCS pressure setpoint of 1500 psig for ESAS High Pressure Injection (HPI) initiation is based on a safety analysis assumption of 1365 psia. This provided more than adequate allowances (150 psig) for loop error / accuracy considerations. The value was considered high enough to provide protection for the entire spectrum of accidents requiring high pressure injection, yet far enough below normal operating pressures to prevent spurious (i.e., undesirable) initiations.

As a result of recent re-analyses of certain small break LOCA's, the previous safety analysis value of 1365 psia was determined to be inadequate for a very narrow range of break sizes. As a result it was determined that the new safety analysis value for the HPI initiation setpoint should be increased. A detailed loop error / analysis calculation was performed by B&W resulting in a new technical specification setpoint of 1526 psig. AP&L has always placed the actual in plant setpoint higher than the minimum allowable technical specification, in fact, the existing setpoint was greater than the 1526 psig value at the time this problem was discovered; therefore, no immediate safety concern existed. However, the required technical specification value of 1526 psig has been observed administratively pending approval of the formal technical specification change.

BASIS FOR PROPOSED NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION The technical specification change requested involves only a change in the setpoint as reflected by computer simulations of various design basis accidents. The computer analysis supports establishment of a different setpoint than that previously required by earlier analysis; however, the new setpoint is still within currently established plant setpoints; therefore, the change in the technical specification setpoint does not increase the probability or consequences of an accident previously evaluated. In either case, the safety system actuation would have occurred at the same point.

The change merely affects the value at which the safety system is required to actuate in response to postulated accidents, and involves no new hardware or modifications to plant design. Therefore, it in no way creates the possibility of new or different kind of accidents from any previously evaluated.

The margin of safety which is under consideration relates ~to the ability to provide prompt ESAS (i.e., high pressure injection) actuation in response to various accidents. The revised safety analysis demonstrates that plant setpoints must ensure HPI initiation at 1480 psig in order to ensure prompt high pressure injection. This is obtained by placing actual setpoints such

r that sufficient allowances for loop error effects and worst case hardware inaccuracies are made. The previous technical specification setpoint used an overly conservative error allowance to ensure prompt ESAS initiation.

The proposed setpoint has been established using state of the art error calculation methodologies. Although the absolute value of the allowances are different, they both demonstrate that prompt ESAS initiation is obtained as required. The error calculations are sometimes referred to as " error margins" leading to confusion with the terminology of " margin of safety."

The margin of safety is in fact preserved by ensuring that the error calculations / analyses were performed and are conservative regardless of the particular methodology used. Therefore, the margin of safety has not been reduced.

Based upon the above, it can be seen that the proposed amendment request does not involve a Significant Hazards Consideration.

The Commission has provided guidance concerning the application of the Significance Hazards Consideration Determination by providing certain examples (40 CFR 14870). Since the computer re-analyses which resulted in the need for the proposed change was a result of changes in regulations (NUREG 0737 item II.K.3.30), this proposed amendment matches item (vii):

(vii) "A change to make a licensee conform to changes in the regulations, where the license change results in very minor changes to facility operations clearly in keeping with the regulations."

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