ML20154C229

Responds to 880505 Request for Temporary Waiver of Compliance from Tech Spec 3.1.3.4 Re Control Rod Drop Time. Temporary Waiver Granted Until 880512 Subj to Listed Conditions

ML20154C229
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/06/1988
From:	Calvo J Office of Nuclear Reactor Regulation
To:	Tison Campbell ARKANSAS POWER & LIGHT CO.
References
NUDOCS 8805180082
Download: ML20154C229 (5)

Text

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o UN!TED STATES

!" , e NUCLEAR REGULATORY COMMISSION 2 E WASHINGTO*4. t C. .*M

) May 6,1988 Docket No. 50-368 Mr. T. Gene Campbell Vice President - Nuclear Operations .

Arkansas Power and Light Company P. O. Box 551 Little Rcek. Arkansas 72203

SUBJECT:

REOUEST FOR TEMPORARY WAIVEP OF COMPLIANCE FRCM TECHNICAL SPECIFICATION 3.1.3.4 REGARDING CONTROL ROD DROP TIME - ARKAESAS NUCLEAR ONE, UNIT ?

The staff has reviewed your reouest for a temporary waiver of ccmpliance from Technical Srecification (TS) 3.1.3.4 submitted in your May 5. 1988 letter.

Our evaluation of this recuest and the supportirg infortnation supplied with it is presented below.

We recognize that by chocsing to utilize the new test rethod for measuring control rod drop times you were acting in the interest of safety in that the tripping of all cortrol rods siruitaneously using the reactor trip circuit breakers duplicates what actually occurs on a reactor trip. The previous method of testing enly involved tripping cne control rod at a tire using the individual red drive power supply breakers. However., as a result of using the new test method, you deternined that the electronagnetic decay times of the control element drive mechanism (CEDM) hniding coils are approxinately 0.25 seconds greater than under the previous test method. These longer decay times (defined as the time between interruption of power to the CEDM and the unlatching of the control rod) are representative of the actual perforrance of the CEDMs on a reactor trip and make obsolete rod drop test results f rom previous cycles. The increase in rod drop time over previous cycles was found to be fairly uniform for all control rods, as can be seen from the test data supplied in the subrittal. Ycu stated that the cause of the increase in CECM coil decay time appeared to be inherent in the design of l the CECM circuitry; with all of the irdividual rod breakers closed, the CEDM i coil shunt resistance circuits are essentially bypassed, resulting in a lower resistance decay path and therefore a smaller tire constant. Based on the test data and discussions submitted we concur with your detertnination of the cause of the tire ircrease, and also that the possibility of rechanical binding has been ruled out.

This increase in CECM coil decay tire resulted in approxtrately 10 percent of l your control rod drop tires exceeding the 3.0 second limit of Technical Specifica-tion 3.1.3.4 In your letter you reported the results of your evaluation cf the effect of these longer rod drop times on the plant safety analysis for low power events up to 30 percent rated power. You also indicated that you would therefore limit your power level to no higher than 30 percent rated power and would not go above 30 percent rated power without prior Comission approval, 0

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The staff has reviewed the evaluation of the Arkansas Nuclear One, Unit 2 (ANO-2) Final Safety Analysis Report (FSAp) safety anslysis events initiated .

at power levels below 30 percent of rated power, which are most adversely affected by the measured increase in rod drop times. These events are the uncontrolled rod withdrawal, both from a subcritical condition and from a critical condition at 1 percent power, and the zero power control rod ejection.

4 The reevaluation of these icw power events, which incorporated the increased measured rod drop tires in a conservative manner, also incorporated a revised

> control rod reactivity versus position curve based on space-time neutron [

kinetics calculations rather than the previously used steady-state static neutron calculations. The staff has previc9 sly approved this methodology to a determine control rod scram characteristics for other Ccmbestion Engineering designed plants such as Pilo Verde, San Onofre, Waterford-3, Calvert Cliffs, and St. Lucie and finds .it acceptable for application to ANO-2. This '

methodology results in a more realistic determination of scram insertion data which has been shown to more than offset the increased control rod drop times during the initial scram time interval of inportance. Because of this, the staff concludes that the previously determined consequences of these limiting  !

low power events remain bounding. We therefore conclude that you can safely proceed with zero power physics testing in Mode 2 and then proceed into Pode 1 i cperation at r.o higher than the 30 percent power test plateau, as you requested.

3 As stated to you by telephere at approximately 7:45 p.m. (EST) on May 5,1988, your request for a temporary waiver of compliance from Technical Specification i 3.1.3.4 is therefore granted ur.til 5:00 p.m. (EST) on May 12, 1988, subject to

] the following conditions.

l (1) Reactor power shall be restricted to no greater than 30 percent rated power. ,

(2) A Technical Specification Change Request specifying a new requirerent for red drop time must be submitted no later than 5:00 p.m. (EST)

May 9, 1988.  !

We will advise you of our decision cencerning the acceptability of your request  !

for an erergency technical specification change once our review is completed. l t

Singly, i

Jose A. Calvo, Director l Project Directorate - IV Division of Reactor Pro,iects - III, '

f IV, Y and Special Projects  !

cc: See next page DISTRIBUTION Docket File NRC PDR Local PDR PD4 Reading  !

L. Rubenstein J. Calvo P. Noonan C. Harbuck l

, G. Dick L. Kopp W. Hodges J. Callan, RIV [

l D. Crutchfield L. Pubensteth OGC-Rockville E. Jordan -

4 J. Partiow ACRS (10) PD4 Plant File

• Sae previous concurrences:

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i The staff has reviewed the evaluation of the Arkansas Nuclear One Unit 2 l (ANO-2) Finsi Safety Analysis Report (FSAR) safety analysis events initiated at power levels below 30 percent of rated power, which are most adversely effected by the reasured increase in rod drop times. These events are the i uncentrolled red withdrawal, both frcm a subcritical condition and from a

critical eccdition at 1 percent power, and the zero power control rod ejection. .

The reevaluation of these low power events, which incorporated the increased measured rod drop tires in a conservative canner, also incorporated a revised 7 control red reactivity versus position curve based on space-time neutron kinetics calculations rather than the previously used steady-state static neutron calculations. The staff has previously approved this methodology to determine control red scran characteristics for other Combustion Engineering designed plants such as Palo Verde, San Onofre, Waterford-3, Calvert Cliffs,

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and St. Lucie and finds it acceptatfe for application to ANO-2. This i rethodology results in a core realistic determination of scram insertion data which has been shown to more than offset the increased control rod drop times during the initial scram time interval of importance. Because of this, the staff concludes that the previously determined consequences of these limiting low power events remain bounding. Ue therefore conclude that you can safely >

proceed with zero power physics te ving in Fode 2 and then proceed into Pode 1 '

operation at no higher than the 30 percent power test plateau, as you requested. ,

i

. As stated to you by telephone at approximately 7:45 p.m. (EST) on May 5,1988, your request for a temporary waiver of compliance fron Technical Specification  ;

j 3.1.3.4 is therefore granted, subject to the following conditions. 7 Lem64 (

Reactor power shall be restrt ted to no greater than 30 percent (1) rated power. i i (2) A Technical Specification Change Request sp ng a new requirerent I for red drop time must be submitted no later than . 0 p.m. (EST) q May 9, 1988. ,

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May 12, 1988. - . .

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, We will advise ycu of our decision concerning the acceptability of your request i for an emergency technical specification change once our review is completed. '

Sincerely,

'j Jose A. Calvo, Director  ;

Project Directorate - IV ,

j Division of Peactor Projects - III,

! IV, Y and Special Projects cc: See next page DISTRIBUTION Docket FT T NRC PDR Local PDR PD4 Reading i L. Rubenstein J. Calvo P. Noonan C. Harbuck i I G. Dick L. Kopp W. Hodges J. Callan, RIV l 1 D. Crutchfield L. Rubenstein CGC-Rockville E. Jordan  ;

! J. Partlow ACRS (10) PD4Plgt y PD4/L

,b PD4/PM Sy- kD4/D GC- SRX SRXB/j/ RIV 4 i PNoo r CHarbu :sr hCalvo ( WHodges LKopp htalld7 l 05/h 05/4/88 05/d /88 ~-05/(/88 05/ 4 /88 05/3 /88 l/05/06 /88 a

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05/6/ 05/ /88

I The staff has reviewed the evaluation of the Arkansas Nuclear One, Unit 2 (ANO-2) Final Safety Analysis Report (FSAR) safety analysis events initiated at pcwer levels below 30 percent of rated power, which are most adversely affected by the meaturd in:vease in rod drop times. These events are the uncontrolled rod withdrawal, both from a subcritical conditten and from a  ;

critical condition at 1 percent power, and the zero power control rod ejection.

The reevaluation of these low power events, which incorporated the increased -

measured rod drop tires in a conservative manner, also incorporated a revised control rod reactivity versus position curve based on space-time neutrer.

Hnetics calculations rather than the previously used steady-state static neutron calculations. The staff has previously approved this methodology to deterriine centrol red scram characteristics for other Ccmbustion Engineering .

designed plants such as Palo Verde, San Onofre, Waterford-3, Calvert .liffs,  !

and St. Lucie and finds it acceptable for application to ANO-2. This rethodolegy results in a more realistic determination of scram insertion data which has been shewn to rore than offset the increased control rod drop times during the initial scram time interval of importance. Because of this, the staff concludes that the previously determined consecuences of these limiting low power events remain bounding. Ve therefore conclude that you can safely proceed with zero power physics testing in Mode ? and then proceed into Pode 1 eperation at no higher than the 30 percent power test plateau, as you requested, As stated to you by telephcre at approximately 7: 45 p.m. (EST) on May 5, 1988, your request for a temporary waiver cf compliance from Technical Specification 3.1.3.4 is therefore granted until 5:00 p.m. (EST) on May 12, 1988, subject to the following conditiens.

(1) Reactor power shall be restricted to no greater thar 30 percent rated power.

-(?) A Technical Specification Change Request specifying a new requirement for red drop time nust be submitted no later than 5:00 p.m. (EST)

May 9, 1988.

We will advise you cf our decision cencerning the acceptability nf your request i for en energency technical specification change once our review is completed.

Sincerely, G / *

.-2. < d, L/ e [t s, Jose A. Calvo, Director Project Directorate - IV I Division of Reactor Projects - III, IV, V and Special Projects cc: See next page

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1 Mr. T. Gene Campbell Ar, kansas Power & Light Company Arkansas Nuclear One. Unit 2 cc:

Mr. Dan R. Howard, Manager Mr. Charles B. Brinkman, Manager Licensing Washington Nuclear Operations Arkansas Nuclear One C-E Power Systems P. O. Box 608 7910 Woodmont Avenue Russellville, Arkansas 72801 Suite 1310 Bethesda, Maryland 20814 -

Mr. James M. Levine, Executive Director Site Nuclear Operations Mr. Frank Wilson, Director Arkansas Nuclear One Division of Environmental Health P. O. Box 608 Protection Russellville, Arkansas 72801 Department of Health Arkansas Department of Health Mr. Nicholas S. Reynolds 4815 West Markham Street Bishop Cook, Percell & Peynolds Little Rock, Arkansas 72201 1400 L Street, N.W.

Washington, D.C. 20005-3502 Honorable William Abernathy County Judge of Pope County Regional Administrator, Region IV Pope County Courthouse U.S. Nuclear Regulatory Connission Russellville, Arkansas 72801 Office of Executive Director for Operations 611 Ryan Plaza Drive, Suite 1000 Arlingten, Texas 76011 Senier Resident Inspector U.S. Nuclear Regulatory Commission >

1 Nuclear Plart Road Russellville, Arkansas 72801 Ms. Greta Dieus.. Director Division of Environnental Fealth Protection Arkansas Department of Health i 4815 West Markam Street Little Rock, Arkansas 72201 Pr. Robert B. Borsum Babcock & Wilcox Nuclear Power Generation Division 1700 Rockville Pike, Suite 525 Rockville, Maryland 20852 i

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