ML17320A941

Suppl 1 to DC Cook Unit 2,Cycle 5 Sar.

ML17320A941
Person / Time
Site:	Cook
Issue date:	02/23/1984
From:	Copeland R, Stout R, Williamson H SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER
To:
Shared Package
ML17320A942	List: ML17320A941 ML17320A944 ML17320A945 ML17320A946 ML17334A516
References
XN-NF-83-85-S01, XN-NF-83-85-S1, NUDOCS 8403080210
Download: ML17320A941 (16)

Text

XN-NF-83-85 Supplement I Issue Date: 2/23/84 D.C. COOK UNIT 2, CYCLE 5 SAFETY ANALYSIS REPORT By:

R. . Copeland Prepared by:

R. B. Stout, Manager Licensing 5 Sa ety gineering Prepared by:

. E.

Ci';~ i Will samson, r.

Manager

'-'~/ ~:~

Neutroni s 8 uel Mana ement Approved by:

. F. Busselman, Manager Design 'uel Approved by: Pp/j ~: Ji t . A. Sofer, Manager/

Fuel Engineering 8 Technical Services Concurred by:

. N.

M Kivu ~ivy i+

1organ, Manager Proposals 5 Customer Service Engineering 8403080220 840302 PDR ADOCK 05000326 naa PDR ON NUCLEAR COMPANY, Inc.

NUCLEAR REGULATORY COMMISSION DISCLAIMER IMPORTANT NOTICE REGARDING CONTENTS AND USE OF THIS DOCUMENT PLEASE READ CAREFUL!.Y This technical report was rlerived through research and development programs sponsored by Exxon Nuclear Company, Inc. It is being sub-mitted by Exxon Nuclear to the USNRC as part of a technical contri-bution to facilitate safety analyses by licensees of the USNRC which utilize Exxon Nuclear-fabricated reload'uel or other technical sewices provided by Exxon Nuclear. for liaht water power reactors and it is true and correct to the best of Exxon Nuclear's knowledge, information, and belief. The information contained herein may be used by the USNRC in its review of this report, and by licensees or applicants before the USNRC which are customers of Exxon Nuclear in their demonstration of compliance with the USNRC's regulations..

Without derogating from the foregoing, neither Exxon Nuclear nor any person acting nn its behalf:

A. Makes any warranty, express or implied, with respect to the accuracy, completeness, or usefulness of the infor-mation contained in this document, or that the use of any Information, apparatus, method, or process disclosed in this document will not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for dan'ages resulting from the use of, any information, ap.

paratus, method, or process disclosed in this document.

XN- NF- FOO, 766

XN-NF-83-85 Supplement 1 TABLE OF CONTENTS Section ~Pa e

1.0 INTRODUCTION

2~0

SUMMARY

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 2 3.0 CYCLE DESIGN..........................-............-..-;.... 4 4.0 FUEL DESIGN...........-.................................... 5 5.0 THERMAL HYDRAULIC DESIGN ANALYSIS.......................... 6 6.0 ACCIDENT AND TRANSIENT ANALYSIS............................ 7 6.1 LOCA ECCS ANALYSIS..............-......-.............. 7 6.2 PLANT TRANSIENT ANALYSES...... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 7 K

6.3 ROD BOW ANALYSIS.............. P

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 7 7.0 ASSESSMENT OF RADIOLOGICAL CONSEQUE NCES OF ACCIDENTSo ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

8.0 REfERENCES................................................. 10

XN-NF-83-85 Supplement 1

1. 0 INTRODUCTION This report is a supplement to the cycle 5 Safety Analysis Report for D.C. Cook Unit 2. The main report addressed the operating history of the reference cycle, power distribution considerations, control rod reactivity requirements, temperature coefficient considerations, and the control rod ejection accident analysis.

This report presents results of ECCS LOCA, thermal margin, rod bow, and radiological assessment analyses. The ECCS LOCA and plant transient analyses were performed to support operation of the D.C. Cook Unit 2 reactor with 5X of the steam generator tubes plugged. The rod bow analysis was performed because rod bow results are dependent on the plant transient predictions for 5I tube plugging. The radiological assessment was redone using ENC's current radiological assessment methodology, which now in-cludes the generically approved version of RODEX2.

2 .

XN-NF-83-85

, Supplement 1 2.0

SUMMARY

The D.C. Cook Unit 2 nuclear 'plant is scheduled to begin cycle 5 operation in the spring of 1984. The reload (reload batch XN-2) will consist of ninety-two fresh 17x17 fuel assemblies designed by Exxon Nuclear Company. A description of the cycle characteristics as well as the reference cycle are provided in the main cycle 5 Safety Analysis Report(>)

along with the fuel description.

In anticipation of steam generator tube degradation, American Elec-tric Power requested Exxon Nuclear to provide the analyses needed to support operation of D.C.'ook Unit 2 with up to 5X of the tubes plugged.

The ECCS LOCA and plant transient analyses required to support operation with " up to 5X tube plugging, are provided in References 2 and 3, respectively.

For the cycle 4 design, the fuel burnup and plant power were increased. Therefore an assessment was made of the potential radiological consequences of the postulated accidents(4). The NRC had not completed the generic review of RODEX2 which is the Exxon Nuclear fuel performance code, which was used as part of the radiological assessment. The review has now been completed, and the analysis redone usi'ng the approved version. The results of reanalyses(5) show that the previous assessment provides bounding predictions.

A rod bow evaluation, required for assembly burnups greater than 28,000 MWD/MTU, was done using the generically approved Exxon Nuclear methodology. The results indicated that there was margin between the DNBR limit and the minimum DNBR even with the calculated penalty for rod bow.

Also, the calculations showed that the total peaking uncertainty was

XN-NF-83-85 Supplement 1 within design tolerances. Therefore, there is no impact on the design from rod bow.

XN-NF-83-85 Supplement 1 3.0 CYCLE DESIGN The cycle design, reference cycle comparisons, and neutronic charac-teristics of cycle 5 of D.C. Cook Unit 2 are presented in Reference 1. This report also addresses the control rod reactivity requirements, moderator temperature coefficient considerations, and power distribution. The results of all of these analyses confirm that the cycle 5 design will operate within the technical specification limits for a projected cycle length of 17,900 MWD/MT at a core power of 3411 MWt with 10 ppm soluble boron remaining.

XN-NF-83-85 Supplement 1 4.0 FUEL OESIGN A description of the Exxon Nuclear supplied fuel design and design methods is contained in Reference 6. This fuel has been designed to be compatible with the resident fuel and to maintain its mechanical integrity while satisfying the neutronic and thermal hydraulic design requirements.

The creep collapse evaluation in reference 6 was performed using the criterion proposed in the Exxon Nuclear high burnup report (>0). This proposed criterion precludes the formation of gaps in the pellet stack, thus precluding creep collapse of the cladding. The prior creep collapse criterion, that the cladding had to be free-standing throughout its design life, is satisfied up to a peak rod exposure of 40,000 MWO/NTU.

XN-NF-83-85 Supplement I 5.0 THERMAL HYDRAUL'IC DESIGN ANALYSIS The Exxon Nuclear supplied fuel has been designed to be thermal-hydraulically compatible with the co-resident fuel in the D.C. Cook Unit 2 core. This analysis is reported in Reference 7 and is unchanged with the 5X steam generator tube plugging.

7 XN-NF-83-85'upplement I

6.0 ACCIDENT AND TRANSIENT ANALYSES

6. 1 LOCA ECCS ANALYSIS The loss of coolant ECCS analysis was redone for D.C. Cook Unit 2 assuming a 5X steam generator tube plugging level . A detai led description of the analyses and the results are presented in Reference 2.

The report documents operating limits which assure operation of the D.C.

Cook Unit 2 reactor is within cr iteria specified by 10 CFR 50.46 and Appendix K.

6.2 PLANT TRANSIENT ANALYSES The plant transient analyses for D.C. Cook Unit 2 were redone assuming a 5X steam generator tube plugging level. The primary coolant flow was reduced to reflect increased flow resistance in the steam generators. The steam generator heat transfer area was reduced and the effects of the plugging on the limiting transients were analyzed. A f

detailed description of the analyses and the results are presented in Reference 3. These results showed that SAFDL's are not violated for the anticipated operational occurrences and that 10 CFR Part 100 radiological limits are satisfied for postulated accidents.

6.3 ROD BOW ANALYSIS The Exxon Nuclear methodology for computing a rod bow penalty(8) to the departure from nucleate boi ling ratio (DNBR) and for computing the U

effects of rod bow on the total peaking (Fq) uncertainty was being reviewed by the NRC at the time the cycle 4 analysis was presented. Therefore the cycle 4 Safety Evaluation Report (SER) required that the effects of rod bow be assessed for Exxon Nuc 1 ear desi gned fue1 wi th assembly exposures

XN-NF-83-85 Supplement 1 greater than 28,000 MWO/MTU. Since that SER, the Exxon Nuclear methodology was generically approved by the Staff. Using this methodology, the effect of rod bow on the MDNBR for the limiting transient has been reevaluated.

The rod bow penalty for the limiting anticipated operational occurrence (AOO) requires the MONBR to be reduced 13.2X at a peak O.C. Cook Unit 2 assembly exposure of 43,000 MWO/MTU; The approved XNB(g) limit for ONBR is

1. 17. Above this limit fuel failures are not predicted and acceptance criteria are satisfied. To satisfy this limit at a peak O.C. Cook Unit 2

'assembly exposure of 43,000 MWO/MTU, the MDNBR from the limiting AOO must be greater than 1.35. The plant transient analyses for the D.C. Cook Unit 2 with 5X of the steam generator tubes plugged showed that the limiting transient (slow control rod withdrawal) had an MONBR above 1.35. There-fore, no operational penalty is required to account for rod bow.

U Similarly, the changes in the total peaking uncertainty (Fq) and the total peaking (Fq) are within the design tolerances. Therefore, no penalty is required.

XN-NF-83-85 Supplement 1 7.0 ASSESSMENT OF RADIOLOGICAL CONSE UENCES OF ACCIDENTS An analysis of the biological doses received from radiological release during accidents involving high exposure fuel was documented in Reference 4 and submitted for cycle 4 operation of D.C. Cook Unit 2. That report demonstrated that the Exxon Nuclear fuel would not violate the 10 4

CFR 100 off-site radiation dose limits after operating the reactor with increased core power and irradiating the fuel to a batch average exposure of 40,000 MWD/MTU. The isotopic release fractions from the fuel were calculated with the then-current version of the RODEX2 fuel performance code.

Subsequent to that analysis, a revised version of RODEX2 received final generic approval from the NRC. Therefore, the potential doses were reanalyzed using the approved RODEX2 to calculate the release frac-tions(5). The results of that reanalysis showed the previous assessment to be bounding,i.e., the previous assessment predicted larger potential doses.

10 XN-NF-83-85.

Supplement l

8.0 REFERENCES

1. XN-NF-83-85, "D.C. Cook Unit 2, Cycle 5 Safety Analysis Report", Exxon Nuclear Company, October 1983.

2. XN-NF-84-21(P), "Donald C. Cook Unit 2 5g Steam Generator Tube Plugging Limiting Break LOCA ECCS Analysis", Exxon Nuclear Company, February 1984.

3. XN-NF-82-32(P), Revision 2, "Plant Transient Analysis for the Donald C. Cook Unit 2 Reactor at 3425 MWt, Operation with 5X Steam Generator Tube Plugging", Exxon Nuclear Company, February 1984.

4. XN-NF-82-90, "D.C. Cook Unit 2, Potential Radiological Consequences of Incidents Involving High Exposure Fuel". Exxon Nuclear Company, November 1982.

XN-NF-82-90, Supplement 1, "D.C. Cook Unit 2, Potential Radiological Consequences of Incidents Involving high Exposure Fuel", Exxon Nuclear Company, January 1984.

6. XN-NF-82-25(P)(A), "Generic Mechanical Design Report, Exxon 17x17 Fuel Assembly", Exxon Nuclear Company, September 1983.

7. XN-NF-82-37(P), Supplement 1, "D.C. Cook Unit 2, Cycle 4 Safety Analysis Report", Exxon Nuclear Company, September 1982..

8. XN-75-32(P)(A), Supplements 1, 2, 3, 4, "Computational Procedure for Evaluating Fuel Rod Bowing", Exxon Nuclear Company, October 1983.

9. XN-NF-621(P)(A), Revision 1, "Exxon Nuclear DNB Correlation for PWR Fuel Designs", Exxon Nuclear Company, September 1983.

10. XN-NF-82-06(P) Revision 1, "qualification of Exxon Nuclear Fuel for Extended Burnup", Exxon Nuclear Company, June 1982.

XN-NF-83-85 Supplement 1 Issue Date: 2/23/84 DC COOK UNIT 2, CYCLE 5 SAFETY ANALYSIS REPORT Distribution C.A. Brown J.C. Chandler R.A. Copeland W.V. Kayser M.R. Killgore G.F. Owsley R.A. Pugh R.B. Stout T. Tahvili P.M. Wimpy H.G. Shaw/AEP (5)

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