ML20236P533

Forwards Summary Description of Power Rerate Ascension Test Program as Supplemental Info to 960726 LAR Re Plant Power Rerate Program.Revised TS Pages,Encl

ML20236P533
Person / Time
Site:	Monticello
Issue date:	07/01/1998
From:	Hammer M NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20236P537	List: ML20236P533 ML20236P542
References
TAC-M96238, NUDOCS 9807170005
Download: ML20236P533 (9)

Text

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Northem States Power Company Monticello Nuclear Generating Plant 2807 West Hwy 75 Monticello, Minnesota 55362-9637 July 1,1998 US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Supplemental Information Regarding the Monticello Power Rerate (TAC No. 96238)

Ref.1 Letter from M.F. Hammer, NSP to US NRC Document Control Desk," Revision 1 to License Amendment Request Dated July 26,1996 Supporting the Monticello Nuclear Generating Plant Power Rerate Program," December 4,1997 l

As previously discussed with the NRC staff on June 2,1998, NSP is providing supplemental information regarding the Monticello power rerate. This information includes: 1) a summary description of the power rerate ascension test program,2) a confirmation of the acceptability of the revised generic Anticipated Transient Without Scram (ATWS) analysis for Monticello as i described in the cover letter to Ref.1, and 3) administrative changes to certain Technical Specification pages previously submitted as part of Ref.1. This information is included as Attachments 1 though 3 respectively.

This submittal provides supplemental information to NSP's power rerate license amendment request (Ref.1). The changes to this submittal do not affect the determination of no significant  ;

hazards that is included within the power rerate license amendment request. Please contact i Joel Beres at 612-295-1436 if additional information is required. j

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,, , ass Mh it Michael F. Hammer Plant Manager

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/ i Monticello Nuclear Generating Plant  !

9807170005 980701 .

PDR ADOCK 05000263 -

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l c: Regional Administrator-lil, NRC NRR Project Manager, NRC Sr. Resident inspector, NRC State of Minnesota, Attn: Kns Sanda

, J. Silberg, Esq.

l Attachments Affidavit to the Nuclear Regulatory Commission Attachment 1 Summary of Power Ascension Test Program for Power Rerate Attachment 2 Confirmation of Acceptability of Generic ATWS Analysis for Monticello Attachment 3 Administrative Changes to Technical Specification Pages

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UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263 Supplemental Information Regarding the Monticello Power Rerate (TAC No. 96238)

Northern States Power Company, a Minnesota corporation, by letter dated July 1,1998 provides supplemental information to the US Nuclear Regulatory Commission (NRC) regarding the Monticello power rerate. This letter contains no restricted or other defense information. Three attachments are included: Attachment 1 Summary of the Power Ascension Test Program for Power Rerate; Attachment 2 Confirmation of Acceptability of Generic ATWS Analysis for Monticello; and Attachment 3 Administrative Changes to Technical Specification Pages.

NORTHERN STATES POWER COMPANY By OA41AddlJ Michael F. Ha'mmer~

Plant Manager Monticello Nuclear Generating Plant On this l day ofb\ s l@B before me a notary public in and for said County, personally appe& red Michael F. Hammer, Plant Manager, Monticello Nuclear Generating Plant, and being first duly swom acknowledged that he is authorized to execute this document on behalf of Northem States Power Company, and that to the best of his knowledge, information, and belief the statements made in it are true.

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k w e .u sma SamuelI. Shirey wm/,....,.o..OS/$5 E2 Notary Public - Minnesota Sherbume County

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1 Attachment 1 Summary of Power Ascension Test Program for Power Rerate

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.c Introduction

'The rerate power ascension test program has been developed in accordance with the generic power uprate guidelines provided in NEDC-32424P, Generic Guidelines for GE BWR Extended Power Uprate. An evaluation of the generic requirements of NEDC-32424P has been performed, and the applicable Monticello-specific testing requirements have been identified. According to Section 5.11.9 of NEDC-32424P, integrated plant (large) transient testing is not required for power increases of $10%. Since the Monticello power rerate of 6.3% is well within this threshold, large transient testing will not be performed for the Monticello power rerate. The actual plant response to transients that were conducted for the initial Monticello startup testing and the plant response to transients that occurred over 28 years of plant operation has been consistent with the transient analysis performed each cycle.

The power ascension test program is designed to verify the following.

Plant systems affected by the power rerate are within design limits.

Nuclear fuel thermal limits are maintained within expected margins.

The response of the main steam pressure control system is stable.

The response of the reactor water level control system is stable.

The reactor core flow is within design limits and stable.

Setpoint Changes In preparation for increasing power, the applicable plant setpoints will be changed as

' described in the Monticello rerate license amendment request dated December 4,1997.

These setpoints will be changed prior to exceeding the present licensed power rating of 1670 MWt.

PowerAscension from 1670 to 1775 MWt

. The pcwer increase to the rerate power level will be made along a constant rod line by increasing reactor recirculation flow. Steady state conditions will be established after each increment of power increase, and test data will be obtained to confirm the response of plant parameters and system performance. The power ascension will consist of three power increase increments of approximately 35 MWt or 2.1%. The incremental increases provide for a controlled approach to the rerate power level. The power increase increments are listed below.

l Increment 1 1670 MWt to 1705 MWt L increment 2 1705 MWt to 1740 MWt

!- Increment 3.1740 MWt to 1775 MWt System Testing in preparation for power ascension, reactor power will be reduced to 1503 MWt (90% of 1670 MWt), and the desired control rod pattern and core flow will be established. At 1503 MWt, the control system response testing will be performed to obtain base line data. The affected control systems include the main steam pressure control system, the 1

reactor water level control system, and the reactor recirculation flow control system.

Additionally, all applicable plant parameters will be recorded. Subsequent power

' increases from 1503 MWt will be performed along a constant rod line using reactor recirculation flow to increase power. Minor rod adjustments to optimize core performance may be made. These adjustments, if necessary, can be accomplished without significantly affecting the startup testing program. Power will be increased to 1635 MWt, and the control systems response testing will be repeated, and all applicable plant parameters will again be recorded.

From the 1635 MWt level, the reactor power will be increased in increments of 35 MWt using recirculation flow. At each step the reactor will be allowed to reach steady state conditions for recording of plant system parameters. At power levels of 102.1%,104.2%

and 106.3%, a hold point in the power ascension procedure will require that the applicable plant parameters are reviewed against acceptance criteria and that discrepancies, if any, are resolved. At 106.3% (1775 MWt), the relationship between the reactor recirculation system drive flow and the reactor core flow will be verified to be within predicted values. The following is a summary of the activities at each power level.

90.0% (1503 MWt) Control System Response Testing, Data Gathering 97.9% (1635 MWt) Control System Response Testing, Data Gathering 100.0% (1670 MWt) Data Gathering 102.1% (1705 MWt) Data Gathering, Verification of Acceptance Criteria 104.2% (1740 MWt) Data Gathering, Verification of Acceptance Criteria 106.3% (1775 MWt) Data Gathering, Verification of Acceptance Criteria, Reactor Recirculation Flow Verification Acceptance Criteria Acceptance criteria will be specified by two levels. Level 1 acceptance criteria normally relate to the values of process variables assigned in the design of the plant such as the overall stability of the reactor water level control system. If a Level 1 criterion is not satisfied, the plant will be placed in a hold condition until resolution is obtained. Tests compatible with this hold condition may be continued. Following resolution, applicable tests may be repeated to verify the Level 1 criterion is satisfied. Level 2 criteria are associated with system performance expectations such as the settling time of a control l system. If a Level 2 criterion is not satisfied, operating and testing plans would not necessarily be altered. An investigation of the measurements and the analytical prediction techniques would be initiated. Level 1 and 2 criteria were used for initial startup testing at Monticello and have been used for power uprate testing at other GE BWRs.

NSP will incorporate Level 1 and Level 2 acceptance criteria into each system affected by the rerate test program. Examples of affected systems include the Main Steam 2

Pressure Control System, the Reactor Water Level Control System, and the Reactor Recirculation Flow Control System.

Administrative Processes The power ascension will be controlled through a procedure that is reviewed by the Monticello Operations Committee. The procedure will provide detailed instructions on prerequisites, power changes, testing requirements, data gathering requirements, acceptance criteria, and hold points. The procedure will receive a 10 CFR 50.59

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evaluation. A test director will be designated, and a senior line manager will be assigned {

direct oversight responsibilities. The Monticello Operations Committee will review the test i summary and associated data. Management approval of the test summary will be i required prior to each power increment increase. l L

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Attachment 2 1

Confirmation of Acceptability of Generic ATWS Analysis for Monticello l

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, .By Section 9.3.1, Exhibit E, of the Monticello power rerate license amendment dated December 4,1997, NSP stated that according to the previous generic BWR/3 ATWS analysis, the ATWS acceptance criteria would be met at rerate conditions if the following criteria were satisfied:

1) reactor power increase s 20%;

2) dome pressure increase s 70 psi;

3) SRV openin2 setpoints increase s 105 psi; and

4) ATWS high pressure setpoint increase s 85 psi.

The power rerate at Monticello continues to be well bounded by the four generic criteria above. NSP also stated in the transmittal letter to the December 4,1997 submittal that an error had been discovered in the generic ATWS analysis which necessitated a revision, and that NSP would subsequently submit a confirmation of acceptability of the

l. revised generic analysis for the Monticello power rerate. The levision to the generic l ATWS analysis has been completed and submitted to the staff. See Ref.1 below..

l l A plant specific ATWS analysis was performed to address the applicability of the revised j generic BWR/3 ATWS analysis to the Monticello power rerate case. This analysis used l Monticello-specific void coefficients and power shapes at beginning of cycle (BOC),

middle of cycle (MOC), and end of cycle (EOC). Reactor power level was assumed to be 1775 MWt, and reactor dome pressure was assumed to be 1025 psia. The results of the Monticello-specific ATWS analysis demonstrated that the ATWS acceptance criteria continue to be met at rerate conditions.

Ref.1 Letter from W. Marquino, GE, to T.J. Kim, NRC, " Errata dated April 13,1998 to

. Section 3.7 of GE Proprietary Document NEDC-32523P, ' Generic Evaluations of .

General Electric Boiling Water Reactor Extended Power Uprate,' Class Ill, dated March 1997," April 13,1998 l

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