JSP-065-93, Application for Amend to License NPF-62,revising TS 3/4.3.4.2, EOC Recirculation Pump Trip Sys Instrumentation to Revise Frequency for Measuring Breaker Arc Suppression Time

Application for Amend to License NPF-62,revising TS 3/4.3.4.2, EOC Recirculation Pump Trip Sys Instrumentation to Revise Frequency for Measuring Breaker Arc Suppression Time

ML20128K361
Person / Time
Site:	Clinton
Issue date:	02/11/1993
From:	Jamila Perry ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20128K369	List: JSP-065-93, Application for Amend to License NPF-62,revising TS 3/4.3.4.2, EOC Recirculation Pump Trip Sys Instrumentation to Revise Frequency for Measuring Breaker Arc Suppression Time ML20128K388
References
JSP-065-93, JSP-65-93, U-602093, NUDOCS 9302180146
Download: ML20128K361 (7)

Text

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Ultra $ Powo' Company u Chn'on Power Statron P O Bon 678 Chnton, IL 61727 Tel 217 935 6226 J. Stephen Perry Vice Preudent ILLIN9tS 02-II)-LP JSP-065-93 BE.100m February ll, 1993 10CFR50.90 i

Docket No. 50 461 Docutaent Concrol Desk Nuclear Regulatory Cer:anission Washington, D.C. 205S5 -

6

Subject:

Clinton Power Station Proposed Amendnet:t

, of Facility Operatipr. License No. NPF 62

Dear Sir:

e Pursuant to 10CFR50.90, H11nois Power (IP) hereby applies for amendment of Facility Operating 1.icense No. NPF 62, Appendix A -

Technical Specifications, for Clinton Power Station (CPS). This request 4 conrists of proposed changes to Technical Specification 3/4.3.4.2, "End-Of-Cycle Recirculation Pump Trip System Instrumentation." The proposed change would revise the frequency for measuring the breaker arc suppression time from once every 18 sconths to once every 60 tnonths.

A description _of the proposed change and the associated justification (including a Basis For No Significant llazards Consideration) are provided in Attachment 2. A marked up copy of the -

affected page from the current Technical Specifications is provided in Attachment 3. .In addition, an affidavit supporting the facts set torth in this letter nnd its attachments is provided in Attachment 1.

IP has reviewed the proposed change against the criteria of 10CFR51.22 for categorical exclusion from environmental impact con.uidera tions . The proposed change does not involve a significant' hazards consideration, or significantly increase the amounts or change-the types of effluents that may be released off-site. nor does it s,ignificantly increase individual or cuaulative occupational radiation exposures, Based on the foregoing, IP concludes the proposed change meets the criteria given in 10CFR51.22(c)(9) for.a categorical exc'.usion from the requirement for an Environmerital Impact Statement.

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9302180146 DR 930211 4 l- l ADOCK 05000461 em 3L 1

. Page 2 of 2 to U 602093 IP is requesting that this proposed change be re.'iewed on a schedule sufficient to support the fourth refueling outage at CPS, which is currently scheduled to begin on Septen:ber 26, 1993.

Sincerely yours,

.)

S. P Senior Vice President TAB /msh Att actumente cc: NRC Clintec Licensing Project- Manager NRC Resident Office, V 690 NRC Regional III, Regional Administrator Illinois Department of Nucicar Safety s

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Attachment 1 to U 602093 l

i STATE OF ILLINOIS i

COUNTY OF DEWITT l 1 ,

l l

J J. Stephen Perry, being first duly sworn, deposes and says: That '

he is Senior Vice President of Illinois Power Company; that the application for amendmen; of Facility Operating License NPF 62 has been prepared under his supervision and direction; that he knows the contents thereof; and that. to tho best of his knowledge and belief said, application and the facts contained therein are true and correct, DATED: This 81 __ day of Fe'uruary 1993 Signed: M _ _ _

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s'J'g<?cj&::w%

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Subscribedands'iorntobeforemethi,pklB'a'y]ot-)he$ruary

, ego; ); c' 1993. .

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A /O _

Notary Public

' Attachment 2

. to U 602093 Page 1 of 4

. LS87-00d Epektround The Clinton Power Station (CPS) End Of-Cycle Recirculation Pump Trip (EOC RPT) system is designed to supplement the Reactor Protection System (RPS) by recovaring the loss of thermal margin which may occur at the end of-cycle. Flux shapes at the end of cycle are such that the control-

• rods may not be able to ensure that thermal limits.are maintaine.d during <

a design-basis, limiting pressurization transient. The EOC RPT system compensates for this phenomenon by inserting sufficient negative reactivity during the first few feet of rod travel upon a scram caused by fast closure of the turbine control valves or closure of the turbine stop valves. The physical phenomenon involved is that the void reactivity feedback due to a pressurization transient can, near the end of the operating cycle, add' positive reactivity at a faster rate than the control rods can add negative reactivity. _ Therefore, the EOC RPT instrumentation initiates.a recirculation pump trip to reduco coolant flow in the core and reduce the et.. t of the void collapse-associated with the pressurization trensient, this provides additional margin to the core thermal minimum critical power ratio (MCPR) safety limits.

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A fast closure sensor for each of the turbine control valves provides input to the four kP5 logic divisions of the EOC RPT system. Similarly, a position switch for each of the turbine stop valvas provides input to the four logic disisions of the EOC-RPT system. The sensor channel combinational logic in arranged to form a 2 out of 4 logic for the fast closure of turbine control valves and a 2-out-of 4 logic for the turbine stop valves.. The operation of either logic will actuate the EOC-RPT system and trip both recirculation pumps.

CPS Technical Specification Surveillance-Requirement 4.3.4.2.3 requires that the EOC RPT System Response Tima_ Test be performed _for each_ trip function at least once every 18-months. This surveillance ensures that- w the individual channel response times are leas than or equal to the maximum values assumed in the accident analysis. The EOC-RPT System Response Time in defined as the time interval to complete suppression of the electric are between the fully opon contacts of the recirculation -

pump circuit breaker from initial movement of the associated turbine-stop valves and turbine control valves. This surveillance currently requires the measurement of the breaker are suppression time:everyL18 months. Illinois Power (IP) 1 requesting a change'to Technical Specification Surveillance Requirement 4.3.4.2.3 such -that the partion of the response time attributed ':a) treaker are_ suppression be determined on'2 60 month surveilitnce . interval,. as per the Standard Technical Specifications and industry practice, instead of onco every 18 months as -

the current CPS Technical Specifications require.

Descriutien of Proposed Chance in accordance with 10CFR50.90, the-following-changes to Technical-Specification 3/4.3.4.2 are being proposed:

1) Add the fo. lowing sentence to the end of' Surveillance Requirement 4.3.4.2.3:

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Attachment 2 to U 602093 Page 2 of 4

. LS-87 008 "The measured time shall be added to the most recent breaker arc suppression time and the resulting EhD OF-CYCLE RECIRCULATION PUMP TRIP SYSTDi RESPONSE TIME shall be verified to be within its limits.'

2) Add a now Surveillance Requirement 4.3.4.2.4 as follows:

"4.3.4.2.4 The time Interval necessary for breaker are suppression from anergization of the recirculation pump circuit breaker trip coil shall be consured at least once per 60 months."

These proposed changes are ioentified on the marked up copy of the page from the current CPS Technical Specificaticns contained in Attachment 3.

Jurtification for Proposed Chante As described above,_the EOC RPT System Response Time Test is intended to ensure that the actual channel response times do not exceed the maximum values assumed in the accident analya.'.s. Responao times (including the are suppresr ton time) cannot be determined during pover operation (above the 40% rated thormal power bypass point) because operation of the final actuated devices is required and because it would subject the plant to an unnecessary transient or result in the plant being in an unacceptable re61 on of operation with respect to reactor power / core-flow fo11ovin6 the pump trip. In addition, even at low-power or shutdown conditions, measurem nt of the breaker are suppression tima requires the ,

installation of special jumpets and Instrumentation, thua increasing the possibility of an inadvertent scram or actuation. As a result, planning for this test requires specific plant conditions or the simulati.an of conditions which pernit parformance of the test.

Based on the above, it la preferred that this test be periormed during a shutdown leading te an outage. If the test cannot be performed during this time period (due to events or circumstances encountered during plant shutdown or if the plant is shut down by scram), the test must be

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performed during the outage or at the end of the outage just prior to startup. Performance of the test during or at the end of an outage can result in a potential for delay in the completion of the outage. In additton,' accommodating the breaker are suppression measurement may ,

require additional cycling of the reactor recirculation pumps and pump '

breakers thus increasing wear and tear on these components, including the reactor recirculation pump seals (and thus increasing the potential s for seal leakage),

It should be noted that test results obtainod to date indicate that the

- reactor recirculation pump breakers and their arc suppression function are quite reliabis. After three cycles of CPb operation, acceptable resulta have been obtained for every valid breaker arc suppression measurement performed to date, Discussions with the vendor confirm that if the breakers are maintained in accordance with vendor recommendacions, the breaker. arc suppression function will also be l

Attachment 2 to U 602093 Page 3 of 4

, LS87-008 maintained. IP is currently maintaining the breakers in accordance with vendor recomraendatient, .

Therefore, baned on the potentf 31 impact to plant equipment and outage schedules resulting from performance of the test, as well an the reliability of the circuit breakers, the Standard 'fechnical Specifications permit the vetification of the time allotted for breaker src suppress!or to be completed on a 60 wonth frequency. The 60 month frequency is allowed since the time to open che contacts after energitation of the trip co 1 and the are suppression tim % are short and 8

do not apprecirbly change, due to the desi 6n of the brockor opening device and the fact that the breaker is not routinely cycled.

The preposed change will merely bring the CPS Techt.ieal Specificar. ion into conformance with the Standard Technical Specifications. The preposed change only revises the fregunney of the are suppression time verif f.c ation. The EOC RPT System Response Tina vill continue to be determined every 18 months using the resultu of the most recent arc suppression tf.me cent. In addition, the brsaker action will continue to be tested every 18 months as part of the logic system functional test.

Basis For No fdent f t cant llergdn Co,gsideration In accordance with 10CFR50.92, a proposed change to the onorating 1 license (Technient Specifications) 1 ,volves no significant hazards censiderations if operation of the facility in accordance with the 4 proposed change would not: (1) involve a significant increase in the probab!.lity or consequences of any accident previously evaluated, or (2) create the possibility of a new or different Lind of accLdent from any accident previously evaluated, or (3) involve a significant raduction in a margin of safety. This request la evaluated against each of these criteria Lolow.

(1) The proposed change merely brings the current CPS Technical Specificacion into conformance with the Standard Technical Specifications und does not result in any changes to the existing plant design. 1he change to increase the test interval for 4

measurir.g the breaker are suppression time la supported by the reliability of the ECC PPT system circuit breakers . Since the chan$e daes not impact the ability of the EOC RPT system to 4

perform its function, and since the proposed change can reduce the potential for inaavertent scrama or system actuations and unnecessary wear and tear on associated components, this change does not result in a significant increase in the consequences of any accident previously evaluated. As the EOC RPT system is designed to initiate a recirculation pump trip to reduce the peak reactor prnssure end power resulting from a turbino-trip or generator load rejection, the proposed change has no impact on the probability of occurrence of a turbine trip or generator load rejection transient.

1 (2) This sequest does no* result in any change to the plant design nor does it involve a significant change in current plant operation.

{he EOC-RPT System Response Time will continue to be determined I

. Attachment 2

. to U.602093

, Page 4 of 4

, LS 87 008 and the system, including breaker action, will continue to be tested every 18 months. As a result, no new failure modes are introduced, and the request will not create tha possibility of a

, new or different kind of accident from any accident previously evaluated.

(3) The proposed request does not adversely impact the reliability of the EOC RPT system and in fact takes credit for the reliability of systein components to reduce the potential for plant transients.

In addition, the system will continue to perform its design function of providing additional margin to the core therraal MCPR safety limito under end of-cycle conditions. Since this request does not involve an adverse impact to systern operation or reliability, and since the EOC RPT systen, function is not affected by the proposed change, this request doesinot involve a significant reduction in a nargin of safety.

Based upon the foregoing IP concludes that this request does not involve a significant hazards consideration.

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