ML20062N869

Application for Amend to License DPR-22,revising TS Section 3.11, Reactor Fuel Assemblies by Removing Info Re Average Planar Linear Heat Generation Rate & Min Critical Power Ratio.Proposed Rev to Page 1 of 8 from COLR Encl

ML20062N869
Person / Time
Site:	Monticello
Issue date:	01/04/1994
From:	Richard Anderson NORTHERN STATES POWER CO.
To:
Shared Package
ML20062N866	List: ML20062N863 ML20062N869 ML20062N873 ML20062N880
References
NUDOCS 9401240155
Download: ML20062N869 (6)

Text

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i UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT LOCKET NO. 50-263  :

REQUEST FOR AMENDMENT TO OPERATING LICENSE DPR-22 LICENSE AMENDMENT REQUEST DATED January 4, 1994 Northern States Power Company, a Minnesota corporation, requests authorization for changes to Appendix A of the Monticello Operating License as shown on the attachments labeled Exhibits A, B and C. Exhibit A describes the proposed )

changes, describes the reasons for the changes, and contains a Safety Evaluation, a Determination of Significant Hazards Consideration and an Environmental Assessment. Exhibit B contains current Technical specification r pages marked up with the proposed changes. Exhibit C is a copy of the  ;

Monticello Technical Specifications incorporating the proposed changes.

Exhibit D contains current Core Operating Limits Report pages marked up with proposed changes based on approval of this amendment.

This letter contains no restricted or other defeni,e information.

NORTHERN STATES POWER COMPANY By 41 h lbMMD

' /oger O Anderson Director Licensing and Management Issues

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On this day of _Pd"L /GG before me a notary public in and for said" County, p sonally a8peare'd'Ro'ger O Anderson, Director Licensing and Management Issues, and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof, and that to the best of his knowledge, information, and belief the statements made in it are true and that i it is not interposed for delay.

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EXHIBIT A Monticello Nuclear Generating Plant l

License Amendment Recuest Dated Januarv 4. 1994  ;

Evaluation of Proposed Changes to the Technical Specifications -

for Operating License DPR-22 .g Pursuant to 10 CFR Part 50, Section 50.59 and 50.90, the holders of Operating >

License DPR-22 hereby propose the following changes: ,

Proposed Chanaes j Technical Specification 3.ll.A specifies limits for the Average Planar Linear l Heat Generation Rate (APLHGR). The specification states, in parts' l "During two recirculation loop operation, the APLHGR limiting condition for operation for each type of fuel as a function of axial location and average planar exposure shall not exceed limits based on applicable ,

APLHGR limit values which have been approved for the respective fuel and i lattice types as determined by the approved methodology described in '

NEDE-240ll-P-A (GESTAR II). This approval is based on and limited to GESTAR II methodology. When hand calculations are required, the APLHCR for each type of fuel as a function of average planar exposure shall not-  ;

exceed the limiting value for the most limiting lattice (excluding  ;

natural uranium) provided in the Core operating Limits Report."

The Technical Specification Bases state that the APLHGR limits assures that t the peak cladding temperature following the postulated design basis loss-of-  ;

coolant accident will.not exceed the limit specified in 10CFR50, Appendix K.

Specification 3.ll.A specifies the NRC approved analytical methods to be used F to determine APLHCR core operating limits. Technical Specification.6.7.A.7 provides administrative reporting requirements for the submittal of cycle  !

specific core operating limits to the Commission,. and also requires r establishing and documenting the APLHGR limits, or Maximum APLHGR (MAPLHGR),

in the Core Operating Limits Report using the specified NRC approved ,

analytical methods.

We propose the following changes to Technical Specifications 3.ll.A and 6.7.A.7.b. j Revise the section of Technical Specification 3.ll.A concerning two l recirculation loop operation'such that the specification would state:

During two recirculation loop power operation, the APLHGR for each type of fuel as a function of average planar exposure shall not exceed the A-1

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applicable limiting value specified in the Core Operating Limits Report '

(Change A identified in Exhibit B).

Revise Technical Specification 6.7.A.7.b by adding the siemens Power Corporation NRC approved methodology ANF-91-0481(P)(A), " Advanced Nuclear e Fuels Corporation Methodology for Boiling Water Reactors-EXEM BWR Evaluation Model," Siemens Power Corporation (latest approved version) (Change B identified in Exhibit B).

The Monticello Core Operating Limits Report (Page 1 of 8) currently states:

"MAPLHGR limits for each individual fuel lattice design in a bundle design, ,

with appropriate channel bow adjustments are loaded in the process computer and are used in core monitoring calculations." Based on approval of this  ;

proposed amendment, the statement in the Core Operating Limits Report would be revised to state "MAPLHGR limits for each individual fuel lattice design in a bundle design as a function of axial location and average planar exposure,  ;

with appropriate channel bow adjustments, are determined based on the approved  ;

methodology referenced in Monticello Technical Specification 6.7.A.7.b and  ;

loaded-in the process computer for use in core monitoring calculations." [

Exhibit D provides the marked up page of the Core Operating Limits Reports j identifying this proposed change.

In additions we propose changes to the bases for Technical Specification , 3.11.C concerning the Minimum Critical Power Ratio (MCPR). Page 217 of the ,

Monticello Technical Specifications contains a discussion of the calculation methodology for MCPR. The Bases section describes MCPR as being calculated for maximum core flow and the corresponding thermal power along the 105% rated power / flow control line to obtain a limiting bundle relative power and then calculating MCPRs using the limiting bundle power and varying core flows along J the 105% rated power / flow control line. We propose to revise this Bases  !

section to state the following: ,

Flow runout events are analyzed with the purpose of establishing a flow dependent MCPR limit that would prevent the Safety Limit CPR from being reached during a flow runout. A flow runout event is a slow flow and power increase which is not terminated by a scram, but which stabilizes .;

at a new core power corresponding to the maximum possible core flow.

Initial conditions for the transient are set such that.the limiting CPR

! is near the Safety Limit. MCPR values are determined from the resulting ,

change in CPR when core flow is increased to a possible maximum.

Several combinations of initial power, flow, and exposure are analyzed i to cover the range of operability defined by the power / flow map. The calculated flow dependent MCPR limit (MCPRr) for a given core flow is provided in the Core Operating Limits Report (change C in Exhibit B).

Reason for Chances 'f The proposed change to specification 3.11.A eliminates the duplication of  ;

requirements specified in specification 6.7.A.7 and the Core Operating Limits Report for establishing APLHGR limits. In addition, Monticello intends to +

implement a Qualification Fuel Assembly (QFA) program at fuel cycle 17. This program would entail including in the cycle 17 fuel loading a small number of A-2 i 5

assemblies fabricated by a vendor other then General Electric. The QFAs are not considered ' lead test assemblies'. The QFAs include only design features {

that have been used in reload quantities and have been reviewed and approved by the NRC. The purpose of the QFAs is to gain experience with other vendors' >

products prior to evaluating proposals for fuel fabrication. Deletion of the i General Electric methodology from specification 3.ll.A and adding the Siemens methodology to specification 6.7.A.7.b establishes appropriate. requirements j for the determination of APLHGR limits, is consistent with NUREG-1433, f l

" Standard Technical Specifications, General Electric Plant, BWR/4", and removes the need for future changes to multiple technical specifications if  ;

the approved analytical method requires further revisions.

The proposed changes to the Techn) 1 specification Bases concerning MCPR, ,

revises the description of the HF calculation methodology to be consistent  !

with that currently used. ,

f Safety Evaluation ,

The APLHGR is a measure of the average linear heat generation rate of all the  ;

fuel rods in a tuel assembly at any axial location. APLHGR limits are based on two phenomena: ECCS peak clad temperature and thermal-mechanical limits.  ;

In the event of a Design Basis Accident Loss of Coolant Accident (DBA-LOCA), ,

the heat stored in the fuel at the time of the event could significantly [

damage the fuel cladding. Peak cladding temperature is primarily a function  !

of the average heat generation rate of all the rods of a fuel assembly at any -f axial location, thus the APLHGR limit ensures that calculated ECCS peak clad  ;

temperatures at rated conditions conforms to IOCFR50.46. The APLHGR limit l also ensures that fuel thermal-mechanical limits are met by limiting peak fuel l pin power below that at which cladding cracking due to plastic strain or ,

transient condition center line melting would occur. Flow dependent j correction factors provided in the Core Operating Limits Report are applied to  ;

the rated condition's APLHGR limits to assure that 1) the 2200'F peak clad l temperature limit would not be exceeded during a LOCA initiated from less than f rated core flow conditions and 2) the fuel thermal-mechanical design criteria  !

would be met during abnormal transients initiated form less than rated core  ;

flow conditions. The power dependent correction factor provided in the Core {

Operating Limits Report applied to the rated conditions APLHGR limits assures j that the fuel thermal-mechanical design criteria would be met during abnormal 1 transients initiated from all conditions provided in the Core Operating Limits .l Report. l l Fuel type specific APLHGR limits will be established by the respective fuel i vendors, using the NRC approved analytical methods of specification 6.7.A.7.b, for input to the accident analysis to demonstrate compliance with the Monticello Updated Safety Analysis Report. For the QFAs, a relative l assessment (at a consistent assembly planar' power) of the linear heat l generation rate of the average fuel rod, the total heat transfer area, and the unheated surface area will be made to the General Electric fuel design. This relative assessment will ensure that the QFAs have a lower stored energy and improved heat transfer capability relative to the General Electric Fuel assemblies and thus application of the General Electric Fuel Assembly APLHGR A-3 i

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i limits to the QFAs will ensure that the accident analyses acceptance criteria are satisfied. NSP will perform the transient analysis and establish power and flow dependent APLHGR correction factors using the NRC approved analytical methods established in specificatinn 6.7.A.7.b. APLHGR limits for each fuel type as a function of axial location and average planar exposure as established by these analyses are programmed into the plant process computer for use in core monitoring calculations.

Removal from specification 3.ll.A of the approved methodology for the determination of APLHGR limits and inclusion in specification 6.7. A.7.b of the Siemens' approved methodology does not constitute a safety concern since specification 6.7.A.7.b identifies the approved methodology for determination )

of core operating limits. Use of the NRC approved analytical methods identified in specification 6.7.A.7.b will ensure that appropriate limits are established to assure that cladding temperatures do not exceed the limits specified in 10CFR50.46 and that fuel thermal-mechanical limits for the ,

appropriate fuel type aio specified. )

l The proposed change to the Technical Specification Bares concerning the MCPR calculation methodology revises this section to be consistent with the current ARTS analysis.

Determina. tion of Sionificant Hazards Considerations The proposed change to the Operating License has been evaluated to determine whether it constitutes a significant hazards consideration as required by 10 CFR Part 50, Section 50.91 using standards provided in Section 50.92. This analysis is provided below:

The proposed amendment will not involve a sionificant increase in t_hg probability or consecuences of an accident previous 1v evaluated.

The APLHGR limits originate from and are associated with LOCA analyses.

Standard exposure dependent APLHGR limits are generated from LOCA analyses initiated from rated power and flow conditions. For any allowable off power and off flow condition the APLHGR limit is the smaller of the flow dependent or power dependent limit. These limits are also used in the fuel thermal-mechanical analysis and transient analysis. Flow dependent APLHGR requirements will continue to be established based on analysis and fuel type specific limits determined using NRC approved methodologies to ensure that peak transient average planar heat generation rate during these events is not increased above the fuel design basis values. Power dependent APLHGR limits will continue to be established based on analysis and fuel type specific limita determined using NRC approved methodologies to ensure that peak transient average planar heat generation rate during any transient ir not increased above the rated fuel design basis transient values. The proposed amendment establishes appropriate controls to ensure that the APLHCR limits will continue to be determined and established using NRC approved methodology; therefore, this amendment will not cause a A-4

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significant increase in the probability or consequences of an accident ,

previously evaluated for the Monticello plant.

The orooosed amendment will not create the nossibility of a new or  ;

different kind of accident frrm any accident creviously analvred.

The proposed amendment does not involve any modification to plant equipment or operating procedures, nor will it introduce any new failure .j modes. The proposed amendment ensures that cycle specific APLHGR limits j are determined and established using approved methodologies and will not create the possibility of a new or different kind of accident. j The croposed amendment will not involve a sionificant reducticn in 'l the maroin of safety.

The proposed amendment removes duplication which exists in the  !

Monticello Technical Specification for the identification of the l approved analytical methods for establishing the APLHGR core operating  ;

limit. In addition the proposed ainendment adds the NRC approved Siemens' analytical method for the determination of APLHGR limits based I on LOCA/ECCS analyses. Inclusion of the NRC approved Siemen's .]

analytical method ensures proper coordination of the methodology j employed to establish the APLHGR limiting condition for operation'for i each type of fuel as a function of. axial location and average. planar :1 exposure. AILHCR limits will continue to be determined using NRC l approved methodology as established in specification 6.7.A.7.b. The I established APLHOR limits will be verified to be consistent with the I accident analysis contained in the Monticello Updated Safety Analysis Report. The proposed amendment will not involve a significant reduction ,

in the margin of safety.  ;

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Environmental Assessment Northern States Power has evaluated the proposed changes and determined thats'

l. The change does not involve a significant hazards consideration.

2 The changes do not involve a significant change in the type or significant increase in the amounts of any effluent that may be released

- offsite, or

3. The changes do not involve a significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the proposed changes met the eligibility criterion for categorical exclusion set forth in 10 CFR Part 51, Section 51.22(b), an environmental assessment of the proposed changes is not required.

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