ML20040H225
| ML20040H225 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 06/30/1975 |
| From: | Vassallo D Office of Nuclear Reactor Regulation |
| To: | Eicheldinger C WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| Shared Package | |
| ML18023A006 | List: |
| References | |
| NUDOCS 8202170464 | |
| Download: ML20040H225 (7) | |
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NAY 3 01375 Fr. C. Eicheldineer, Panager i
Nuclent Safety tepartment k'estint. house I. lect ric Corporati.
F. O. Cox 355 Pittsburr.h, Pennsylvania 15230 D4;ar Hr. Eicheloicrer:
The fi. clear Regulatory Coor2ission ststf has conpleted its review of the k'estinchouse Electric Corporation Emergency Core Cooling System (ECCS).
evaluation rodel. The codel is defined in Ecferences 1 Lhrour.h 20 of Enclost.a 2.
A su r.sry of our evaluation of bestinghouse's ECCE model is attached as Enclosure 1.
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As a result of our review, we have concluded that the Westinghouse eval-
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untion codel ceets the requirements of Appendix K to 10 Cil: Part 50 and,
. thirefore, is acceptable for use in the ECCS evaluction for the follouing classes'ot plants:
1 - Typical current Uestinghouse' two, three, and four loop plcots.
2 - Plcnts with dry, subatroospheric or ice' containments.
3 - Plant s with poser ratings up to 3500 Wt.
4 - Plants utilizing only botton flooding e erpency core cooline systems.
Therefore, the Pestinghouse reports defining, the ECCS evaluction model.
c.ay be referenced in license applications as accepted for use in E.CCE cnclyses. Ve fird, however, thet the LCIIC code (described in references 4 cnd 5) is not presently cecertable f or deier. wining the rtinicum conLcin-
- rent pressure rest.onse for ell plants usinp ice cencenser containments.
Until such time as the code is modified to resolve our concerns (stated in.%ferences 21 sed 22), a conservative riniruu containment pressure.
of zero psig nust be cssur.ed in the ECCS cnolyset of plcnts with ice condenser ccatzinwents.
We sto:.not intend to repent our review of the !!estinghousc report s listed in. Enclosure 2 khen they ore used in support of the ELCC evcluation rodel.
Our nicept.see,cfNies ot.ly to the use of the relorts as part of the
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.t.est inthouse LCCS evaluction rodel-and does not - c4nst itute occeptance of _the individual report s for.eny purpose. otaer t!.an for 10t:5, cis e.L ys e s.
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N B202170464 B20212 PDR ADOCK 05000445 O
t Mr. C. Eiche1dinger MAY 3 01975 L'e consider the. non-proprietary reports, listed in Enclosure 1, acceptable i
versions of the corresponding proprietary reports listed in Er. closure 1.
j-When either a proprietary report or a non proprietary version of a proprietary i
report is used as a referecc'e, both the proprietary report and its ncn-proprietary version must,be included in the reference.
If you have any cuestions about our review of the bestinghouse ECCS eval-untion model, please contact us.
Sincerely, m -
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D. E. Vassallo, Chief Light lister nesctors 1roject 'Eranph 1-1 Division of heactor Licensing
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Enclosures:
1.
Su: mary of Staff Evaluation of.
p ECCS liodel 2.
List of L'estinrhouse Eerorts.
Describing ECCS 1:odel
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j ENCLOSURE 1 t
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NRC Staff Review of the Westinghouse Emergency Core Cooling System Evaluation Model e
Background Information Westinghouse submitted a description of the Westinghouse Emergency Core
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Cooling System (ECCS) evaluation model on August 5,1974, in several '
reports (References 1 through 18 of Enclosure 2).
The NRC staf f reviewed the August submittal for conformance with the requirements of Appendix K i
to 10 CFR Part 50 entitled "ECCS Evaluation Models," and published its evaluation in "Otatus Report by the Directorate of Licensing in the Matter of the Westinghouse ECCS Evaluation Model Conformance to 10 CFR Part 50, Appendix K" (Reference 21) dated October 15, 1974.
This report addressed each requirement of Appendix K, discussed confor=ance by Westinghouse.
indicated the acceptability of the analytical methods employed in the Westinghouse model', and assessed the impact of specific open ite,ms which were either unresolved or unacceptable.
Additional documentation was subsequently submitted by Westinghouse addressing these open items and the staff review entitled " Supplement to the Status Report by the Directorate of Licensing in the Hatter of
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Westinghouse Electric Company ECCS Evaluation Model Conformance to 10 CFR 50 Appendix K " was published on November 13,1974 (Reference 22).
We concluded that certain modifications, which ' vere described in the above mentioned documents, were required to achieve conformance with
' Appendix K to 10 CFR Part 50 On October 26 and November 14, 1974, the staff presented its assessment of the Westinghouse evaluation model to the Advisory Committee on Reactor Safeguards (ACRS).
In its report to the Chairman of _the AEC, dated November 20, 1974, the ACRS concluded. that "the four light-water reactor vendors have developed evaluation models which, with additic a1 modifications required by the staf f, will conform to Appendix K to Part 50."
The required model changes which were subsequently implemented by Westinghouse into their evaluation model included the following:
1 - Deletion of rod-to-rod radiation during blowdown.
'2 - Revision of the injection se'etion pressure drop.
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3 e Delet' ion of t'he 10% clad strain burst criterion.
4*, Inclusion of. a hot wall time delay.
5 - Modifi~ cati ~ ens ~to the steam cooling model for_reflood rates less than 1 inch /second.
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On December 27, 1974, the Commission, in response to licensee submittals of additional information from operating Westinghouse plants, pursuant to Section 50.46 and Appcndir r to 10 CFR Part 50, issued a Sa'fety Evaluation l
Report and Orders for Modification of Licenses pertaining to the latest proposed Technical Specifications. In addition, the Commission requested 3
that the above modifications to the Westinghouse evaluation codel be made and that a reanalysis be submitted within six months.
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3 On April 17,'1974, Westinghouse formally submitted proprietary and non-proprietary versions of a topical report (References 19 and 20) which documented all of the modifications required by the staff in October and November 1974 (References 21 and 22).
In addition to the modifi-s cations required by the staff, Westinghouse submitted supplemental information to complete the documentation requirements of Ap'pendix K, including responses to questions raised by the staf f in the course of reviewing the Westinghouse ECCS evaluation model, refine =ents to the steam cooling model, and documentation of minor modifications which had no significant effect on computational results.
Conclusions The NRC staf f has completed its review of the Westinghouse ECCS eval-untion model which is comprised of References 1 through 20 We closely followed the development of the Westinghouse ECCS evaluation model
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and utilized the referenced reports to determine the compliance of the Westinghouse evaluation model with Appendix K to 10 CFR Part 50. The details of our review are summarized in References 21 and 22. We conclude:
1.
That the Westinghouse evaluation model is an acceptable model to be.used for ECCS performance evaluation for plants which satisfy the following plant classifications:
Typical current Westinghouse two, three, and four loop a.
plants.
b.
Dry, subatmospheric or ice containments.
c.
Power ratings up to 3800 MWt.
d.
Plants utilizing only bottom flooding emergency core cooling systems.
2.
That References 1 through 20, which constitute the consolidated description of the Westinghouse ECCS evaluation model, may be incorporated by reference in licensing applications as an accepted ECCS -evaluation.model. This acceptance applies 4o the Westinghouse ECCS model. and does not constitute acceptance of the individual reports for any purpose other than for ECCS analyses.
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3.
The application of the LOTIC code for purposes of ECCS performance evaluation, in determining the minimum containment pressure response for all ice containments, will be evaluated on a plant-by-plant basis. Until such time that LOTIC is modified to resolve the staff concerns, noted in references 21 and 22, a conservative minimum contai6 ment pressure of zero psig must be assumed in ECCS i
analyses of plants using an ice condenser containment.
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ENCLOSURE 2 REFERENCES t
1.
WCAP-8200, Rev. 2, "WFLASH - A Fortran IV Computer Program for Simulation of Transients in a Multi-Loop PWR," (Proprietary), June 1974.
2.
WCAP-8261, Rev.1, "WFLASH - A Fortran IV Computer Program for Simulation of Transients in a Multi-Loop PWR," (Non-proprietary), July 1974.
3.
" Effects of Fuel Densification Power Spikes on Clad Thermal Transiests," (Non proprietary), July 1974.
4.
WCAP-8354 "Long-Term Ice dondenser containment Code - LOTIC Code,"
(Proprietary), July 1974.
5.
WCAP-8355 "Long-Term Ice condenser Containment Code - LOTIC code,"
(Non-proprietary), July 1974.
6.
" Westinghouse ECCS '- Plant Sensitivity Stud'ies," (Proprietary),
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July 1974.
7.
" Westinghouse ECCS - Plant sensitivity Studies," (Non-proprietary), July 1974.
8.
" Containment Pressure Analysis Code (COCO)," (Proprietary),
July 1974.
9.
" Containment Pressure Analysis Code (COCO)," (Non-proprietary),
July 1974.
10 WCAP-8302
" SATAN-VI Program:
Comprehensive Space-Time Dependent Analysis of Loss-of-Coolant," (Proprietary), June 1974.
11.
" SATAN-VI Program:
Comprehensive Space-Time Dependent
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Analysis of Loss-of-Coolant," (Non-proprietary), June 1974.
12.
" Calculational Model for Core Reflooding After a LOCA (WREFLOOD Code)," (Proprietary), June 1974.
13.
" Calculational Model for Core Reflooding After a LOCA
. (WREFLOOD Code)," (Non proprietary), June 1974.
- 14. ' WCAP~-6301 - TLOCTA-IV Program:
Loss-of-Coolant Transient Analysis,"
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(Proprietary-), June 1974.
15 WCAP-8305
"'LOCTA-IV Program': Loss-of-Coolant Transient Analysis,"
.(Nc6-proprietary), June 1974.
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- 17. WCAP-8341
- Westinghouse ECCS Evaluation Mode 1' Sensitivity Studies,"
I (Proprietary), July 1974.
- 18. WCAP-8342
" Westinghouse ECCS Evaluation Hodel Sensitivity Studies,"
(Non-proprietary), July 1974.
- 19. WCAP-8471
." Westinghouse ECCS Evaluation Model - Supplementary Infor-mation," (Proprietary), January 1975.
- 20. WCAP-8472
Westinghouse ECCS Evaluation Model - Supplementary Infor-mation," (Non-proprietary), January 1975 21.
" Status Report by the Directorate of Licensing in the Hat' tar of Westinghouse Electric -Company ECCS Evaluation Model Conformance to 10 CFR 50, Appendix.K,',0ctober 15, 1974.
22.
" Supplement to the Status Report by the Directorate of Licensing in the' Matter of Westinghouse Electric Company ECCS Evaluation Model Conformance to 10 CFR 50, Appendix K," November 13, 1974.
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