NG-95-2969, Application for Amend to License DPR-49 Re RPT Operability & Surveillance Requirements

Application for Amend to License DPR-49 Re RPT Operability & Surveillance Requirements

ML20094M408
Person / Time
Site:	Duane Arnold
Issue date:	11/15/1995
From:	Franz J IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	Russell W NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20094M411	List: ML20094M413 NG-95-2969, Application for Amend to License DPR-49 Re RPT Operability & Surveillance Requirements
References
NG-95-2969, NUDOCS 9511270046
Download: ML20094M408 (6)

Text

'

IES Utilities Inc.

, 200 First Street SE.

b PO. Box 351 Cedar Rapids. If 52406-0351 Telephone 319 398 8I62 Fax 319 398 8192 UTILITIES John E Franz. Jr. I Vice Pressdent, Nuclear November 15,1995 NG-95-2969

.Mr. William T. Russell, Director Of6ce of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Attn: Document Coatrol Desk Mail Station PI-37 Washing:on, DC 20555-0001

Subject:

Duane Arnold Energy Center Docket No: 50-331 Op. License No: DPR-49 Request for Technical Specification Change RTS-286, (EOC)RPT Operability and Surveillance Requirements File: A-117

Dear Mr. Russell:

In accordance with the Code of Federal Regulations, Title 10, Sections 50.59 and 50.90, IES Utilities Inc. hereby requests revision to the Technical Specifications (TS) for the Duane Arnold Energy Center (DAEC).

The proposed amendment would revise the requirements for the End of Cycle Recirculation Pump Trip logic to match more closely the assumptions applicable to the turbine trip events for which it was installed. The surveillance requirements are also proposed to be revised, bastd on those same assumptions.

This application has been reviewed by the DAEC Operations Committee and the Safety Committee.

A copy of this submittal, along with the evaluation of No Significant Hazards Consideration, is being forwarded to our appointed state of6cial pursuant to 10 CFR Section 50.91.

In order to allow dequate time for implementatior, . request that the proposc'. TS amendment be made effective 90 days from issuance.

Should you have any questions regarding this matter, please contact this of9ce.

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Mr. William T. Russell NG-95-2%9 November J5,1995 Page 2 This letter is true and accurate to the best of my knowledge and belief.

IES UTILITIES INC.

By /D6

/ohn F. Frani /

Vice President, Nuclear State oflowa (County) of Linn I Signed and sworn to before me on this /[ day of NMtA[f A ,1995, byhp$)Q 0 n#qbsh /

DEBRA J. SCHWENKER

" m 7"'

Notary Public in and for the State ofIowa Commission Expires Attachments: 1) Evaluation of Change Pursuant to 10 CFR Section 50.92

2) Pronc3ed Change (RTS-286) to the DAEC Technical Specifications

3) Environmental Consideration

4) Safety Assessment JFF/SRC/ch N:\lowa\ Licensing \rts\rts-286. doc cc: S. Catron L. Liu B. Fisher G. Kelly (NRC-NRR)

H. Miller (Region III)

S. Brown (State ofIowa)

NRC Resident Office Docu

..- +

RTS-286 - Attachment I to NG-95-2969 -

i Page1of4 - l i

. EVALUATION OF CHANGE PURSUANT TO 10 CFR SECTION 50.92 l i

Background:

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The End of Cycle Recirculation Pump Trip ((EOC)RPT) system was installed at the Duane Arnold  :

Energy Center (DAEC) in 1980 to increase the margin to the reactor fuel safety limit for Minimum Critical Power Ratio (MCPR) during the transients involving turbine trips at the end of an OPERATING CYCLE while at reactor power greater than or equal to 30%. The system consists of instruments arranged in two trains of logic which monitor the position of certain turbine valves, in '

order to initiate the' opening of the reactor recirculation pump motor-generator set output circuit breakers. Tripping the recirculation pumps reduces the core flow and thereby adds negative reactivity which counteracts the positive reactivity added by the pressurization associated with a  ;

turbine trip. I The existing Technical Specifications (TS) require that reactor power be reduced to below 85% m the event that the (EOC)RPT system is not OPERABLE. The intent is to maintain an adequate 4 margin to the safety limit (SL) MCPR. However, with current fuel designs, this margin can be _

readily _ met with little or no reduction in reactor power. This proposed amendment would impose an l operating limit (OL) MCPR penalty on continued plant operation to maintain that necessary margin to the SLMCPR as an alternative to requiring a power reduction.

Additionally, there may be entire OPERATING CYCLES during which the (EOC)RPT would not be required because of sufficient margin to the OLMCPR. Consequently, IES will have the option to operate' the DAEC with the (EOC)RPT in bypass and accept the resulting OLMCPR penalty in order to minimize the potential for spurious trips of the recirculation pumps and unnecessary surveillances of the (EOC)RPT which require that plant operating power be reduced.

During development of this TS change request, it was determined that the " Minimum Operable Channels Per Trip System" and the " Response Time" acceptance criteria should be input speciGe in order to ensure that the (EOC)RPT performs as designed.

IES Utilities Inc.. Docket No. 50-331.

Duane Arnold Enercy Center. Linn County. Iowa Date of Amendment Reauest: November 15,1995 Descriotion of Amendment Reauest:

The proposed TS amendment would revise the " Applicable Operating Mode" to recognize that the (EOC)RPT is bypassed below 30% rated thermal power. It would revise the " Minimum Operable Channels per Trip System" to recognize that there is a need to maintain one channel of each type of input in ords to satisfy the TS. It would revise the Action Statement to require implementation of an OLMCFP penalty for continued operation without the (EOC)RPT. That OLMCPR penalty would be OPERA *1iNG CYCLE-specific and derived from the ditTerence in MCPR ca!culated for the turbine trip events with (EOC)RPT in service and out of service. That penalty would be included in the DAEC cycle-specific CORE OPERATING LIMITS REPORT (COLR). The proposed I amendment would also revise the Surveillance Requirements to increase the surveillance interval for l

j: RTS-286 Attachment I to l NO-95-2969 Page 2 of 4 i

with the Improved Standard TS, NUREG 1433, and to revise the response time acceptance criteria based on recent reviews of the assumptions and the testing methodology. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> LIMITING L CONDITION FOR OPERATION and subsequent 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> to implement the OLMCPR penalty remain unchanged from the current time limits for (EOC)RFI' logic out of service and time to reduce  ;

power, respectively.  ;

Basis for Proposed No Signincant Hazards Consideration:

The Commission has provided standards (10 CFR Section 50.92(c)) for determining wh iner a significant hazards consideration exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the propsed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety. <

After reviewing this proposed amendment, we have concluded:

1) The proposed TS amendment will not significantly increase the probability or consequences of any previously evaluated accidents. The (EOC)RPT system was installed to preclude violation of reactor fuel limits, and the system will be preserved for that purpose. In the event that system is not available, an operating penalty will be imposed on the MCPR limit to assure sufncient margin to the limit to preclude fuel damage during the postulated turbine trip events.

The change to the " Minimum Operable Channels per Trip System" will assure that inputs monitoring both the turbine control valve fast closure and the turbine stop valve closw will be available to initiate (EOC)RPT.

The change to the " Applicable Operating Mode" is an editorial change which reflects the existing hardware bypass.

The change to Action 81 in TS Table 3.2-G will assure that when the (EOC)RPT system does not meet the minimum TS availability requirements, the SLMCPR will not be challenged. By imposing a OLMCPR penalty for continued operation, the fuel thermal limits will not be challenged, since the (EOC)RFI' system was installed to accomplish the same goal. No increase in the consequences of the turbine trip events will result from this change. The OLMCPR penalty is dependent on cycle-specific parameters and will therefore be included in the cycle-specific COLR.

The change to the surveillance interval results in (EOC)RPT logic channel functional tests being performed once per quarter instead of once per month. The change also revises the allowed out-of-service time (AOT) for testing from two hours to six hours. These changes are consistent with the Improved Standard Technical Specifications, NUREG-1433, Revision 1. The (EOC)RPT is initiated by instruments common to the Reactor Protection System (RPS) (i.e., turbine stop valve closure and turbiae control valve fast closure). The surveillance interval and AOT changes for these instruments were evaluated in " Technical Specification Improvement Analysis for BWR Reactor Protection System," NEDC-30851P-A, March 1988, for the RPS function. Although the (EOC)RPT functions were not explicitly identified in that document, these changes can be considered bounded by that analysis. The basis for this conclusion is similar to the basis established for the control rod block

- I RTS-286 Attachment 1 to NG-95-2969 Page 3 of 4 1

instrumentation common to the RPS, as documented in " Technical Specification Improvement Analysis for BWR Control Rod Block Instrumentation," NEDC-30851P-A, Supplement 1, October 1988. Failure of the (EOC)RPT function could potentially lead to exceeding the SLMCPR, similar 1 to the consequences of an unmitigated rod withdrawal error. The slight increase in risk of a l I

SLMCPR violation due to extending (EOC)RPT surveillance interval and AOT is offset by the same benefits associated with the similar approved surveillance interval and AOT for the RPS. ' Both the j above referenced reports have been approved for application at the DAEC via TS Amendment 193, l dated April 14,1993.

l The changes to the " Operating Modes for which Surveillance Required" are clarifications and will

.I result in a more efficient utilization of resources. By stating that the surveillance applies only when l the (EOC)RI7I' system is OPERABLE, the surveillances will not be performed needlessly. During l the early part of an OPERATING cycle, the (EOC)RPT is not required to mitigate a turbine trip, and 1 therefore, may be bypassed. At the time when the (EOC)RPT is assumed to be OPERABLE )

pursuant to the analysis, it will be made OPERABLE unless accepting the penalty on the OLMCPR I is preferable. The result of the proposed change will still be that the (EOC)RPT is demonstrated

- OPERABLE at any time when it is required. .

The change to the acceptance criteria for response time testing reflects a recent review of the analytical assumptions and the testing methodology. The (EOC)RI7T is assumed to interrupt power 1 to the recirculation pump motor within 175 milliseconds after initiation of either turbine stop valve closure or turbine control valve fast closure. The response time test only measures a portion of the complete trip (the rest was measured as part of start-up testing). The portion measured is dependent on which trip input is being tested. The turbine control valve closure is sensed by a pressure switch monitoring the hydraulic fluid controlling the valve and therefore has no delay between valve motion and initiation of the (EOC)RPT logic. The turbine stop valve closure is sensed by position switch.

Since this switch is set to initiate (EOC)RPT at 10% valve closed, there is a brief delay between the beginning of valve motion and initiation of the (EOC)RPT logic. The respective proposed response time tests account for these differences, as described in the footnotes on TS page 3.2-36, and demonstrate that the measured portions of the action are within the allowed time periods, l None of the proposed changes will significantly increase the probability of any accident previously evaluated because the (EOC)RPT is not an initiator of any of those events. None of the proposed changes will significantly increase the consequences of an accident because the (EOC)RPT system serves to prevent a turbine trip event from exceeding the fuel SLMCPR, and it will continue to perform in that capacity at any time when it is required to assure margin to the SLMCPR.

2) The proposed changes will not add a new or different kind of accident beause the plant will not be operated in a different way. By allowing the implementation of a penalty on OLMCPR in lieu of reducing reactor power, the risk of a plant transient is reduced. Similarly, the surveillance interval and AOT extensions will also result in fewer plant power reductions for testing.

1

, The (EOC)RPT initiates a trip of the recirculation pumps and any TS change affecting that system cannot result in an effect on any system other than those pumps. Consequently, no new accidents are postulated as a result of thi; proposed change.

RTS-236 Auachment I to NG-95-2969 Page 4 of 4

3) The proposed change will not result in a significant reduction in any margin of safety. The (EOC)RPT performs to assure adequate margin to the SLMCPR. The proposed change will preserve that function and require that additional margin to the SLMCPR be imposed for those times when the (EOC)Riiis not OPERABLE. The other changes are proposed because they assure correct (EOC)RPT function (inputs and response times).

Based upon the above, we have determined that the proposed amendment will not involve a significant hazards consideration.

Local Public Document Room Location: Cedar Rapids Public Library,500 First Street SE, Cedar

{

Rapids, Iowa 52401

]

Attorney for Licensee: Jack Newman, Kathleen H. Shea; Morgan, Lewis & Bockius,1800 M Street NW, Washington, D.C. 20036-5869 i

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