L-05-133, Supplement to License Amendment Request Nos. 310 and 182

Supplement to License Amendment Request Nos. 310 and 182

ML052220351
Person / Time
Site:	Beaver Valley
Issue date:	08/08/2005
From:	Pearce L FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-05-133
Download: ML052220351 (7)

Text

FENOC Beaver Valey Power Station FirstEnergy Nuclear Operating Company Shippingport. PA 15077-0004 L. William Pearce 724-682-5234 Vice President Fax: 724-643-8069 August 8, 2005 L-05-133 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

Subject:

Beaver Valley Power Station, Unit Nos. 1 and 2 BV-1 Docket No. 50-334, License No. DPR-66 BV-2 Docket No. 50-412, License No. NPF-73 Supplement to License Amendment Request Nos. 310 and 182 By letter dated July 6, 2005, the U.S. Nuclear Regulatory Commission (NRC) issued a request for additional information (RAI) pertaining to FirstEnergy Nuclear Operating Company (FENOC) License Amendment Request (LAR) Nos. 310 and 182 (Reference 1). The Reference 1 submittal proposes implementation of the Relaxed Axial Offset Control (RAOC) and FQ surveillance methodologies.

Attachment A contains the FENOC responses to the July 6, 2005 RAI questions. The responses contained in this transmittal have no impact on the proposed Technical Specification changes, or the no significant hazards consideration, transmitted by Reference l.

No new regulatory commitments are contained in this submittal. If you have questions or require additional information, please contact Mr. Henry L. Hegrat, Supervisor -

Licensing, at 330-315-6944.

I declare under penalty of perjury that the foregoing is true and correct. Executed on August j 2005.

Sincerely, William Pearce GCod

Beaver Valley Power Station, Unit Nos. 1 and 2 Supplement to License Amendment Request Nos. 310 and 182 L-05-133 Page 2

Attachment:

A. Responses to RAI dated July 6, 2005

Reference:

1. FENOC Letter L-05-009, License Amendment Request Nos. 310 and 182, dated February 11, 2005.

c: Mr. T. G. Colburn, NRR Senior Project Manager Mr. P. C. Cataldo, NRC Senior Resident Inspector Mr. S. J. Collins, NRC Region I Administrator Mr. D. A. Allard, Director BRP/DEP Mr. L. E. Ryan (BRP/DEP)

L-05-133 Attachment A REQUEST FOR ADDITIONAL INFORMATION RELATED TO FIRSTENERGY NUCLEAR OPERATING COMPANY (FENOC)

BEAVER VALLEY POWER STATION, UNIT NOS. I AND 2 (BVPS-1 AND 2)

RELAXED AXIAL OFFSET CONTROL (RAOC)

DOCKET NOS. 50-334 AND 50-412 By letter dated February 11, 2005 (Reference 1), FENOC (the licensee), proposed changes to BVPS-1 and 2 Technical Specifications (TSs) to allow implementation of the RAOC and F0 surveillance methodologies in accordance with WCAP-10216-P-A, "Relaxation of Constant Axial Offset Control F0 Surveillance Technical Specification" (Reference 2).

FENOC currently has a pending license amendment request (LAR) for extended power uprate (EPU) (Reference 3). FENOC has requested that the LAR to implement RAOC be approved in time to allow a concurrent implementation of the EPU. The Nuclear Regulatory Commission (NRC) staff requests responses to the following information in order to complete the review of the licensee's RAOC LAR:

1. WCAP-10216-P-A delineates a calculational procedure for determining the final RAOC limit. From the.licensee's submittal it is not evident that the procedure was explicitly followed. Please provide a description of how the calculational procedure of WCAP-10216-P-A was followed. Please justify any exceptions to the calculational procedure identified in WCAP-10216-P-A.

Response

The methodology for the implementation of RAOC and F0 surveillance presented in WCAP-10216-P-A has been formalized in the Westinghouse Core Design Procedure Manual - Engineering Services Manual (ESM). The RAOC calculational procedures presented in this manual incorporate the methodology from WCAP-10216-P-A, including the use of design codes specifically developed to prepare the RAOC analysis, the automation of various calculational sequences, and the incorporation of lessons learned during the design and operation of plants using the RAOC and F0 Technical Specifications.

The design calculations performed to support the first-time implementation of the RAOC and F0 Technical Specifications for the Beaver Valley Power Station units were documented and verified by Westinghouse for FENOC using the methodology presented in the Engineering Services Manual. Therefore, the calculational procedure delineated in the NRC approved WCAP was explicitly followed and this analysis meets all of the requirements from WCAP-10216-P-A.

It should be noted that the presentation of the results of this analysis in the RAOC LAR may not have included a discussion of all intermediate steps in the process, but the complete process was followed per the procedures in the Engineering Services Manual for the implementation of the RAOC and Fa Surveillance Technical Specifications.

2. On page A-16 of WCAP-10216-P-A, paragraph 2, "F0 Analysis," it is stated, "Each power shape generated in Section C.1, above is analyzed to determine if LOCA

[loss-of-coolant accident] constraints are met or exceeded. The total peaking factor, FQT, is determined using standard synthesis methods as described in WCAP-8385...." Yet in the EPU LAR, the licensee is deleting WCAP-8385 from the list of approved methodologies. Please identify the replacement for WCAP-8385.

Please provide the justification for that replacement.

L-05-133 Attachment A Page 2 of 5

Response

The deletion of WCAP-8385 and the addition of WCAP-10216-P-A are shown in the EPU LAR markups because the RAOC methodology (WCAP-1 0216-P-A) will replace the constant axial offset control (CAOC) methodology (WCAP-8385) in the upcoming fuel cycles during which the EPU will be implemented. The deletion and addition of these WCAPs in the EPU markups reflect the changes submitted in the RAOC LAR. Since WCAP-10216-P-A references WCAP-8385, WCAP-8385 is incorporated by reference in the technical specifications, in it's proper context and need not be referenced separately.

3. FENOC's EPU LAR indicates the EPU analysis was performed assuming constant axial offset control (CAOC). Since the accident analysis submitted with EPU LAR indicates that the departure from nucleate boiling analysis assumes the most limiting axial and radial power shapes possible during the fuel cycle, how do the more limiting axial power shapes allowed by RAOC affect those analyses?

Response

In addition to the original analysis with CAOC, additional RAOC analysis was performed for the EPU conditions to widen the allowed Al-Power operating space while ensuring that safety considerations are satisfied.

Specifically, the departure from nucleate boiling (DNB) calculations were performed for EPU accident analysis using the limiting axial power shapes assumed to be bounding for the possible operation during the fuel cycle. For the RAOC implementation, the validity of the axial power shape assumption is verified by DNB power shape analysis.

Sufficient margins were retained in the original CAOC analysis to support the RAOC implementation without affecting the results of the EPU safety analysis.

The limiting normal operation power shape assumed in the DNB analysis for accidents starting from normal operation is confirmed to be bounding for Condition I power shapes generated using RAOC methodology.

Core limits and axial offset limits are the basis of the plant protection trip setpoints that specify the region of allowable operation. These limits are generated based on reference Condition II axial power shapes that are assumed to be bounding. For the RAOC implementation, those limits have been confirmed to be valid. Although more limiting axial power shapes are allowed by RAOC operation, DNB analysis shows that they are bounded by the reference axial power shapes. The trip setpoints are confirmed to assure that the plant operation will be within the allowable region defined by the DNB design basis for the RAOC conditions.

For subsequent RAOC operations, the limiting axial power shapes will be confirmed on a cycle-by-cycle basis in accordance with the current reload evaluation methodology.

L-05-133 Attachment A Page 3 of 5

4. FENOC's EPU LAR is adding the non-loss-of-coolant accident (non-LOCA) methodology, WCAP-14565-P-A, "VIPRE-01 Modeling and Qualification for Pressurized Water Reactor Non-LOCA Thermal-Hydraulic Safety Analysis,"

(Reference 4) to the list of NRC-approved methodologies appearing in BVPS-1 and 2 TS 6.9.5.b. A requirement of WCAP-14565-P-A, Is that reactor boundary conditions such as power shape are shown to be conservative for each use of VIPRE. As the EPU LAR utilized power shapes developed with the CAOC methodology, please show how power shapes developed using RAOC remain conservative with the use of VIPRE.

Response

The core boundary conditions for the VIPRE calculations are all generated from NRC approved codes and methodologies. Axial power shapes generated for RAOC are more limiting than those for CAOC analysis. A sufficiently large number of power shapes are generated covering a large area of Al-Power space and are examined to assure that limiting shapes have been generated. The most limiting shapes are used in VIPRE calculations. This is justified through the DNB power shape analyses, which shows that the RAOC shapes are bounded by the reference axial power shapes used in core limits and axial offset limits. Therefore, the power shapes used in RAOC analysis are conservative for the use of VIPRE.

5. According to WCAP-14565-P-A, VIPRE predictions were found to be sensitive to axial noding but once sufficient noding detail is obtained, the results were found to be insensitive to further noding detail. Please identify whether VIPRE has any additional axial node sensitivity for power shapes generated utilizing the RAOC methodology as opposed to those generated with the CAOC methodology.

Response

The finite difference method used in the VIPRE code requires that sufficient axial nodes be provided to resolve the details in the flow field and the axial power shapes. For the VIPRE model, the maximum nodal length along the heated fuel length is generally consistent with the nodal length used in the previous THINC model. The THINC nodal lengths provide good accuracy for the RAOC power shapes, and no additional axial node sensitivity study is required with the VIPRE model.

For RAOC analysis, the power shapes analyzed are more limiting than those from CAOC analysis. The DNB power shape analysis has confirmed that the power shapes generated using RAOC methodology are bounded by the reference limiting power shapes used in design basis. The use of power shapes generated using RAOC does not impose any additional axial node sensitivity for VIPRE calculations.

L-05-133 Attachment A Page 4 of 5

6. Please identify any other methodology constraints, conditions, or restrictions that may be impacted by the use of axial power shapes generated using the RAOC methodology as opposed to those generated using the CAOC methodology.

Please provide justification for the use of RAOC generated axial power shapes for all identified impacts.

Response

The thermal-hydraulic methodology used to analyze axial power shapes generated by the RAOC analysis is similar to those used in the CAOC analysis. Condition I power shapes are evaluated relative to the assumed limiting normal operation power shape used in the DNB analysis for accidents starting from normal operation. Condition II (Accident) power shapes are evaluated relative to the reference axial power shapes assumed in the DNB analysis for the core limits and axial offset limits. The trip setpoints are justified to assure that the DNB design basis is met for the RAOC operation by specifying the allowable region based on the core limits and axial offset limits.

The RAOC implementation is in full compliance with the NRC Safety Evaluation Report conditions in WCAP-10216-P-A and WCAP-14565-P-A. For each reload, the power shapes used in the accident analysis will be verified with the RAOC generated axial power shapes on a cycle-by-cycle basis in accordance with the reload methodology described in WCAP-9272-P-A.

The Fuel Rod Design methodology described in the EPU LAR is not dependent on which specific axial offset control strategy is implemented. In either case the appropriate axial power shapes, operating bands, and fuel duty are input to the Fuel Rod Design codes to ensure that all Fuel Rod Design criteria are met. Therefore, no methodology constraints, conditions, or restrictions will be impacted by the use of the axial power shapes generated using the RAOC methodology as opposed to those generated using the CAOC methodology.

L-05-133 Attachment A Page 5 of 5 REFERENCES

1. FirstEnergy Nuclear Operating Company (FENOC), letter dated February 11, 2005 from L. William Pearce, Site Vice President to USNRC, re: Beaver Valley Power Station, Unit No. 1 and No. 2, BV-1, Docket No. 50-334, License No. DPR-66, BV-2 Docket No. 50-412, License No. NPF-73, License Amendment Request Nos. 310 and 182.

2. WCAP-10216-P-A, "Relaxation of Constant Axial Offset Control/FQ Surveillance Technical Specification."

3. FirstEnergy Nuclear Operating Company (FENOC), letter from L. William Pearce, Site Vice President to USNRC, re: Beaver Valley Power Station, Unit No. I and No. 2, BV-1 Docket No. 50-334, License No. DPR-66, BV-2 Docket No. 50-412, License No. NPF-73, License Amendment Request Nos. 302 and 173.

4. WCAP-14565-P-A, "VIPRE-01 Modeling and Qualification for Pressurized Water Reactor Non-LOCA Thermal-Hydraulic Safety Analysis."