ML041490334

Units 1 and 2, Errors or Changes in the Emergency Core Cooling System Evaluation Model; Annual Report for 2003

ML041490334
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/27/2004
From:	James D Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
OCAN050404
Download: ML041490334 (11)

Text

~Entergy Operations, Inc.

En tab 1448 S.

R.

333 Russellville. AR 72802 Tel 501 858 5000 1 OCFR50.46(a)(3)(ii)

OCAN050404 May 27, 2004 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Subject:

Arkansas Nuclear One - Units 1 and 2 Docket Nos. 50-313 and 50-368 License Nos. DPR-51 and NPF-6 Errors or Changes in the Emergency Core Cooling System Evaluation Model; Annual Report for 2003

Dear Sir or Madam:

10CFR50.46(a)(3)(ii) requires licensees to report annually each change to or error discovered in an acceptable evaluation model or in the application of such model for the emergency core cooling system (ECCS) that affects the peak cladding temperature.

Included in this submittal is the estimated effect the changes or errors identified during the reporting period from January 1, 2003, through December 31, 2003, have on the limiting ECCS analysis.

This report fulfills the reporting requirements referenced above.

This submittal contains no commitments. Should you have any questions regarding this submittal, please contact Richard Scheide at (479) 858-4618.

Sincerely jr E.James

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M ager, Licensing DEJ/rhs Attachment

cc:

Dr. Bruce S. Malleft Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 U.S. Nuclear Regulatory Commission Attn: Mr. Thomas Alexion Mail Stop 0-7 DI Washington, DC 20555-0001 U.S. Nuclear Regulatory Commission Attn: Mr. Drew Holland Mail Stop 0-7 DI Washington, DC 20555-0001

Attachment to OCAN050404 Page I of 9 1.0 ANO-1 2003 LOCA EM Error CorrectionslChanges and Evaluationsl 1.1 BWOG Generic Information Applicable to ANO-1 1.1.1 CRAFT2 Evaluation Model Error Corrections or Changes No errors or changes were reported in the CRAFT2-based B&W ECCS EM, BAW-10104P-A, Rev. 5 for LBLOCA (Reference 1.1) and BAW-10154-A, Rev. 0 for SBLOCA (Reference 1.2),

during 2003. Currently, all B&W plants rely on the BWNT LOCA EM (Section 1.1.2) to support the cycle-specific LOCA LHR limits. However, certain plants may rely on evaluations and analyses performed with the CRAFT2-based EM to support evaluation of older fuel designs that may be reinserted into a core design, plant operational guidance, or equipment qualification.

• No changes or errors 1.1.2 BWNT LOCA Evaluation Model Error Correction or Changes This evaluation model (EM) is applicable to all B&W-designed pressurized water reactors for large and small break LOCA analyses for zircaloy or M5 cladding. The NRC-approved topical report for this EM is BAW-10192P-A Rev 0 (Reference 1.3).

The large break LOCA Evaluation Model consists of four computer codes:

1.

BAW-10164P-A, RELAP5/MOD2-B&W to compute the system, core, and hot rod response during blowdown (Reference 1.4),

2.

BAW-10171P-A, REFLOD3B to calculate the time for refill of the lower plenum and core reflood rate (Reference 1.5),

3.

BAW-10095-A, CONTEMPT to compute the containment pressure response (Reference 1.7), and

4.

BAW-10166P-A, BEACH (the RELAP5/MOD2-B&W reflood heat transfer package) to determine the hot pin thermal response during refill and reflood phases (Reference 1.6 and Reference 1.11).

The small break LOCA Evaluation Model consists of two codes:

1.

BAW-10164P-A, RELAP5/M0D2-B&W to compute the system, core, and hot rod response during the transient (Reference 1.4), and

2.

BAW-10095-A, CONTEMPT to compute the containment pressure response (Reference 1.7), if needed.

An NRC-approved fuel code (currently BAW-10162P-A, TACO3 (Reference 1.9) or BAW-101 84P-A, GDTACO (Reference 1.10)) is used to supply the fuel rod steady-state conditions at I

Aftachment to OCAN050404 Page 2 of 9 the beginning of the small or large break LOCA. These codes are approved for use with M5 cladding as discussed in BAW-10227P-A (Reference 1.8).

It should be noted that the most recently approved versions of the EM and associated topical reports are referenced above. However, the plant and fuel-type-specific licensing calculations may be based on an earlier approved method and thus not specifically utilize the enhanced features that were subsequently approved or submitted as a change via 50.46. A summary of the intermediate EM changes and EM error corrections made to BAW-10192P-A is discussed in Section 1.1.4.4.

One EM change in the RELAP5IMOD2-B&W-based BWNT LOCA EM occurred during 2003.

1.1.3 BWNT LOCA Evaluation Model Generic Analyses One generic B&W evaluations were completed in 2003.

Error Correction for Containment Pressure Input for 177-FA Lowered-Loop LBLOCA Analyses An error was discovered in the input of the mass and energy data input to the CONTEMPT model. The error originates from allowing the CONTEMPT code to linearly interpolate in the mass and energy data that was generated over distinct time intervals. The result is that the CONTEMPT integrated mass and energy release is not consistent with the system analyses, and the LOCA containment pressure response is overpredicted.

Reference 1.15 summarizes the effect of correcting the mass and energy input to certain CONTEMPT analyses that define the containment pressure input to LBLOCA analyses for the 177-FA lowered-loop analyses performed prior to 2003. The correction of this error results in a reduction of the containment pressure.

A characteristic of LOCA analyses for the lowered-loop plant design is that the LBLOCA PCT tends to occur just after the end of the adiabatic heat-up period. Lowering the containment pressure increases the CFT injection flow during the refill period, which shortens the adiabatic heat-up period and reduces the PCT.

• Application Error Correction - Containment pressure error from CONTEMPT

• PCT changes associated with this Application Error Correction are reported in the plant-specific sections.

1.1.4 Generic EM Information General information related to the EM topical reports and associated modeling guidance is provided below.

These topics do not constitute EM changes or error corrections, and are provided as information.

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Aftachment to OCAN050404 Page 3 of 9 1.1.4.1 Approval of BEACH Topical Report Revision AREVA previously submitted a revision to the BEACH topical report for large break analyses to extend (i) the range of application for the maximum cladding temperature limit to 2045 F for BEACH, (ii) the minimum reflood rate to 0.4 in/sec, and (iii) the minimum applicable containment pressure to 14.7 psia. The extension of the cladding temperature limit to 2045 F was previously reported via 50.46 reporting.

The NRC, by letter dated November 7, 2003 (Reference 1.11), approved Revision 5 of the BEACH topical report, BAW-101 66P, and its use with the once-through steam generator large break and small break LOCA evaluation models, BAW-10192P-A.

• There are no PCT changes associated with this topic.

1.1.4.2 Approval of Reactor Coolant Pump Degradation Model Change for RELAP5/MOD2-B&W Preliminary Safety Concern 2-00 investigated SBLOCAs with reactor coolant pump (RCP) operation beyond the time of turbine trip. It was discovered that more severe consequences could be predicted for larger SBLOCAs when the RCPs were manually tripped at one to two minutes following loss-of-subcooling margin, and that these consequences were even worse when the M3-modified RCP degradation model (lower bound providing least pump degradation) was applied. The NRC, by letter dated April 10, 2003 (Reference 1.12), approved the use of the M3-modified two-phase reactor coolant pump degradation multiplier in RELAP5/MOD2-B&W for resolution of PSC 2-00. This approval is contingent upon each licensee establishing that the M3-modified curve is conservative for each licensee's plant. AREVA has prepared generic material to justify the use of the M3-modified curve with respect to the plant-specific reactor coolant pumps. This material is currently being reviewed for submittal to the NRC. Use of the M3-modified RCP degradation multiplier was previously applied as an EM Change in 2000 and 2001.

• There are no PCT changes associated with this topic.

1.1.4.3 Change to RELAP5/MOD2-B&W Evaluation Model Guidance Documents Several ancillary guidance documents that supplement BAW-10192P-A and the code topical reports were created or updated in 2003 to facilitate the uniform application of the approved methods.

They make no changes to the approved methods used to perform licensing calculations.

Limitations and Restrictions on BAW-10192P-A (Reference 1.13)

This guidance document outlines the NRC limitations and restrictions imposed on BAW-10192 and the associated code topical reports. The document was revised to include recent NRC approvals.

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Attachment to OCAN050404 Page 4 of 9 RELAP5 Modeling Guidelines (Reference 1.14)

This guidance document outlines generic RELAP5/MOD2-B&W modeling practices and was revised to incorporate more detailed information and recent NRC approvals.

CONTEMPT Modeling Guidelines (Reference 1.15)

This guidance document outlines generic CONTEMPT modeling practices for use in LOCA containment pressure calculations.

TACO3/GDTACO Output Guidelines (References 1.16 and 1.17)

These documents describe the conversion of the output from the TACO3 and GDTACO3 steady-state fuel initialization cases to input to the RELAP5/MOD2-B&W code.

REFLOD3B Methods (Reference 1.21)

This document reviews the history of the various REFLOD3B models utilized in B&W plant licensing calculations and identified categories of REFLOD3B input parameters to facilitate updating of future models.

REFLOD3B Output Guidelines (References 1.18, 1.19 and 1.20)

These documents describe the conversion of the output from the REFLOD3B code to input to the BEACH code.

• No 50.46 changes or corrections are discussed.

1.1.4.4 Outline of Evolution of BAW-10192P-A Changes The general outline for application of the Evaluation Model is described in BAW-10192P-A.

The code topical report revisions identified in BAW-10192P-A Rev. 0 for use in LOCA analyses are:

BAW-10164P-A, Revision 3, RELAP5/MOD2-B&W, BAW-10171P-A, Revision 3, REFLOD3B, BAW-101 66P-A, Revision 4, BEACH, BAW-10095-A, Revision 1, CONTEMPT, and BAW-10162P-A, Revision 0, TACO3.

Since the approval of BAW-10192P-A, the codes and methods have evolved through approved code revisions, identification of specific codes not identified in the EM, and the addition of new methods and error corrections made under 10 CFR 50.46. The following NRC-approved topical reports have been added as part of the EM. However, these revisions are not explicitly identified in BAW-10192P-A Rev. 0.

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Attachment to OCAN050404 Page 5 of 9 BAW-10164P-A, Revision 4, RELAP5/MOD2-B&W BAW-10166P-A, Revision 5, BEACH BAW-10227P-A, Revision 0, M5 Cladding BAW-10184P-A, Revision 0, GDTACO The addition of new methods and error corrections made under 10 CFR 50.46 are reported to the utilities at least annually for including in plant-specific 50.46 reports to the NRC.

In the case of new methods, acceptable licensing cases are typically not reanalyzed or reevaluated in order to take advantage of the new methods. (Error corrections are applied to current licensing basis cases as necessary.) Therefore, the last acceptable licensing cases for a specific plant may not have been performed with the most recent EM changes (approved or made via 50.46).

• No 50.46 changes or corrections are discussed.

1.2 ANO-1 Specific Information In addition to the changes identified in Section 1.0, the following licensing analyses or evaluations were performed in 2003 and are applicable to ANO Unit 1. Limiting ECCS analyses are tracked for the Mark-B9 fuel rod design for the RELAP5-based EM. In Cycle 18, the ANO-1 licensing basis was switched from the CRAFT2-based EM to the RELAP5-based EM.

Therefore, the CRAFT2-based licensing calculations are not reported for 2003.

Error Correction for Containment Pressure Input for 177-FA Lowered-Loop LOCA Analyses The error in the containment pressure input to LBLOCA, discussed in Generic Issue 0, affected the ANO-1 Mark-B9 analyses. The most recent applicable LBLOCA analyses for the Mark-B9 fuel were performed with EM RO.3. (The limiting SBLOCA analysis is based on EM RO.5.)

Analyses were specifically performed for Crystal River-3 to determine the magnitude of the PCT change for correction of this error. The PCT change determined for CR-3 is also applicable to the ANO-l LBLOCA analyses.

Therefore, new PCTs were estimated for application to the Mark-B9 fuel (Reference 1.2). The limiting PCT and PCT changes are described in Reference 1.34.

• The LBLOCA PCT change for Mark-B9 fuel is estimated to be (-32) F.

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Attachment to OCAN050404 Page 6 of 9 1.3 References 1.1.0 AREVA Topical Report BAW-101 04P-A, Rev. 5, "B&W's ECCS Evaluation Model,"

November 1988.

1.2.0 AREVA Topical Report BAW-10154-A, Rev. 0, "B&W's Small-Break LOCA ECCS Evaluation Model," July 1985.

1.3.0 AREVA Topical Report BAW-10192P-A, Rev. 0, "BWNT LOCA - BWNT Loss-of-Coolant Accident Evaluation Model for Once-Through Steam Generator Plants," June 1998.

1.4.0 AREVA Topical Report BAW-10164P-A, Rev. 4, "RELAP5/MOD2-B&W -

An Advanced Computer Program for Light Water Reactor LOCA and Non-LOCA Transient Analysis", November 2002.

1.5.0 AREVA Topical Report BAW-10171P-A, Rev. 3, "REFLOD3B - Model for Multinode Core Reflooding Analysis", December 1995.

1.6.0 AREVA Topical BAW-10166P, Rev. 5, "BEACH - A Computer Program for Reflood Heat Transfer During LOCA", December 2001.

1.7.0 AREVA Topical Report BAW-10095-A, Rev. 1, "CONTEMPT - Computer Program for Predicting Containment Pressure-Temperature Response to a LOCA", April 1978.

1.8.0 AREVA Topical Report BAW-10227P-A, Rev. 1, "Evaluation of Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel", June 2003.

1.9.0 AREVA Topical Report BAW-10162P-A, Rev. 0, "TACO3 Fuel Pin Thermal Analysis Code", October 1989.

1.10.0 AREVA Topical Report BAW-10184P-A, Rev. 0, "GDTACO Urania - Gadolinia Fuel Pin Thermal Analysis Code", February 1995.

1.11.0 Letter dated 11/7/03 from H. N. Berkow USNRC to J. F. Mallay (Areva), "Issuance of Revised Safety Evaluation for Referencing of Appendices H and I to BAW-10166P-A, "BEACH - Best Estimate Analysis Core Heat Transfer, A Computer Program for Reflood Heat Transfer During LOCA", (TAC No. MC0341)", USNRC ADAMS Accession Number ML033140275.

1.12.0 Letter dated April 10, 2003 from H. N. Berkow USNRC to J. Mallay (Areva),

Subject:

Evaluation of Framatome ANP Preliminary Safety Concern (PSC) 2-00 Relating to Core Flood Line Break and Operator Action Time (TAC No. MA 9973), Project No. 728.

1.13.0 AREVA Proprietary Document 51-5001731-02, "BWNT LOCA EM Limitations and Restrictions", 6/4/03.

1.14.0 AREVA Proprietary Document 51-1203953-02, "R5/M2 B&W Plant LOCA Modeling Guidelines", 6/2/03.

1.15.0 AREVA Proprietary Document 32-5025388-00, "BWNT LOCA Containment Pressure Calculation Guidance", 5/30/2003.

1.16.0 AREVA Proprietary Document 32-5023856-00, "T3XN Script Development", 5/30/03.

1.17.0 AREVA Proprietary Document 32-5023856-01, "T3XN Script Development", 7/2/03.

1.18.0 AREVA Proprietary Document 32-5022597-00, "R3DOC Script Development and Usage", 6/4/03.

1.19.0 AREVA Proprietary Document 32-5022597-01, "R3DOC Script Development and Usage", 7/2/03.

1.20.0 6

Attachment to OCAN050404 Page 7 of 9 1.21.0 AREVA Proprietary Document 32-5022597-02, "R3DOC Script Development and Usage", 11/4/03.

1.22.- AREVA Proprietary Document 51-5019524-00, "R3 Input Deck History and Model Updates", 6/2/03.

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Attachment to OCAN050404 Page 8 of 9 2.0 ANO-2 2003 LOCA EM Error Corrections/Changes and Evaluations 2.1 Generic Information Applicable to ANO-2 2.1.1 Evaluation Model Generic Information Five evaluation models (EM) for ECCS performance analysis of PWRs developed by Combustion Engineering are described in topical reports, are licensed by the NRC, and are covered by the provisions of 10CFR50.46. The evaluation models for large break LOCA (LBLOCA) are the June 1985 EM and the 1999 EM. There are two evaluation models for small break LOCA (SBLOCA); the SBLOCA Evaluation Model (SIM) and the S2M SBLOCA EM. Post-LOCA long term cooling (LTC) analyses use the LTC evaluation model.

Several digital computer codes are used to do ECCS performance analyses of PWRs for the evaluation models described above that are covered by the provisions of 1 OCFR50.46.

Those for LBLOCA calculations are CEFLASH-4A, COMPERC-II, HCROSS, PARCH, STRIKIN-II, and COMZIRC. CEFLASH-4AS is used in conjunction with COMPERC-II, STRIKIN-Il, and PARCH for SBLOCA calculations. The codes for post-LOCA LTC analyses are BORON, CEPAC, NATFLOW, and CELDA.

There were no changes to or errors in the ECCS evaluation models for PWRs or changes to their operation for calendar year 2003 that affect the calculated cladding temperature.

There is no PCT effect for the post-LOCA long term cooling evaluation models.

2.1.2 Westinghouse Generic Model Corrections and Changes The code problems described below were addressed in 2003. They have no impact on the PCT; therefore, they are not reported under the provisions of 1 OCFR50.46. This information is provided for completeness in the reporting process.

RADENCL calculates information for the radiation enclosure (pin-to-box ratio, X-factor, and related input) for use with the STRIKIN-il hot rod heat-up calculation for LBLOCA.

A situation was identified in which the RADENCL code experiences a fatal error and fails to produce its normal output. The error occurs when the hot rod is not adjacent to the water hole which is an assumption used in the original software design for RADENCL. This was the situation until more recent fuel bundle designs and fuel management practices that can produce a hot pin at any location in the fuel bundle.

Version RAD. 1.3 of RADENCL was created with changes to identify when the hot rod is not adjacent to a water hole, print a warning message and complete the calculation. Other changes were made to update the version identification, proprietary notice and copyright information.

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Attachment to 0CAN050404 Page 9 of 9 There is no impact on the 10CFR50.46 acceptance criteria including PCT due to these changes in RADENCL.

2.2 ANO-2 Specific Information The ANO-2 specific effect for the LBLOCA analysis of power uprate with the 1999 EM is less than 10F. The SBLOCA PCT effect for the power uprate analysis with the S2M SBLOCA methodology is +240F. This change was reported to the NRC in ANO's 2002 ECCS report. Both of these analyses were performed for Cycle 16 operation. Cycle 16 completed in 2003 and Cycle 17 started in 2003. These analyses are applicable to Cycle 17 as well.

2.3 ANO-2 References

1.

CENPD-279, Supplement 1, "Annual Report on Combustion Engineering ECCS Performance Evaluation Model for PWRs".

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