ML19322C412
| ML19322C412 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/11/1980 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| TLL-015, TLL-15, NUDOCS 8001170284 | |
| Download: ML19322C412 (5) | |
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Metropolitan Edison Company Post Of fice Box 480
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Middletown, Pennsylvania 17057 717 9444 041 Writer's Direct Dial Number January 11, 1980 TLL 015 Darrell G. Eisenhut, Acting Director Division of Operating Reactor Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Units I & II (TMI-l & TMI-2)
License Nos. DPR-50 & DPR-73 Docket Nos. 50-289 & 50-320 Fuel Cladding Swelling & Rupture Thi.s letter and the attached evaluation is in response to your letter of Nove.mber 9, 1979, addressing portions of ECCS evaluation models dealing with fuel cladding swelling and incidence of rupture.
We have reviewed the available material and have concluded that the representations made by Babcock and Wilcox in our behalf are correct.
The attached evaluation provides the details of our review.
Sincerely,
\\
i fn J. G. Herbein Vice President Nuclaar Operations JGH:CFM: hah Attachment r
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Metropol. tan Ecson Company s a Memter of the General Puct'c Utit.es System 80011702 N
METROPOLITAN EDISON COMPANY JERSEY CENTRAL POWER & LIGHT COMPANY AND PENNSYLVANIA ELECTRIC COMPANY THREE MILE ISLAND NUCLEAR STATION, UNITS I & II c
Operating License Nos. DPR-50 and DPR-73 Docket Nos. 50-289 and 50-320 This letter is submitted in support of the Nuclear Regulatory Commission request concerning portions of ECCS evaluation models dealing with fuel cladding swelling and incidence of rupture, dated November 9, 1979 for Three Mile Island Nuclear Station, Units I & II.
As part of this response an " Evaluation of NRC Clad Swelling Concerns" is attached. Further, all statements contained in this report have been reviewed and all such statements
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made and matters set forth therein are true and correct to the best of my knowledge, information and belief.
METROPOLITAN EDISON COMPANY By.
Vice President Sworn and subscribed to me this 9th day of January 1980.
By l
aNotary Public,
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Attachm:nt 1 TLL 015 An Evaluation of NRC Clad Swelling Concerns In response to Reference 1 GPUSC/ Meted has reviewed the information on fuel cladding swelling and rupture models for LOCA analysis.
Both the Staff Analyses and the corresponding B&W responses to NRC concerns (Reference 2 through
- 5) have been considered. Based upon our review we concur with the B&W conclusion that the new NRC cladding data do not change the results of previously completed safety analyses for both TMI-I and TMI-II, and that no further analyses are necessary.
This conclusion is based on the following:
(1)
As demonstrated in Reference 2, the approved B&W evaluation model is in conformance with Appendix K, 10CFR50 in that the present clad strain and assembly blockage models are based on applicable data and do not under-estimate the degree of swelling C
and incidence of rupture. The models are fully applicable to TMI-I and II.
(2)
ECCS calculations utilizing the presently-approved models demonstrate that the peak cladding temperature (22000F) and other criteria of 10CFR50.46 are not exceeded for either TMI-I or TMI-II (Reference 2).
(3)
There are specific instances where the preliminary NRC models appear to be more conservative than the B&W models over limited ranges (e.g., individual pin strain). However, the B&W model for large breaks overpredicts both the incidence of rupture and the degree of flow blockage as compared to the NRC fast ramp curves.
The B&W small break model does not predict significant cladding heatup and, therefore, swelling and flow blockage are not'of concern for small~ breaks.
(Reference 2 and 3)
. (4)
Furthermore, incorporation of the NRC ramp heatup, clad strain,.
and flow blockage models in the B&W ECCS evaluation model, as applicable to TMI-I and II, would not result in violation of the 10CFRSO.46 PCT or other criteria (References 2, 3, 4).
In summary, our review concludes that the information presented to the Commission regarding the presently-approved B&W ECCS evaluation model, including clad strain and assembly flow blockage models, is correct and applicable to both TMI-I and TMI-II.
The evaluation model is in compliance with the requirements of Appendix K and the limits of 10CFR50.46, even utilizing the new NRC models. Further, JPUSC/ Meted concurs with the B&W opinion that no model changes or further analyses are appropriate or necessary as a result of the information presented in the NUREG-0630 draf t.
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References:
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1.
Letter, NRC (D. G. Eisenhut) to All Operating Light Water 3
Reactors, dated November 9,1979.
2.
Letter, B&W (J. H. Taylor) to NRC (D. G. Eisenhut), dated November 2, 1979.
3.
Letter, B&W (J. H. Taylor) to NRC (D. G. Eisenhut), on B&W Cladding Rupture Model for LOCA Analyses, dated November 9, 1979.
i 4.
Letter, B&W (J. H. Taylor) to NRC (D. G. Eisenhut), on same I
subject, dated November 20, 1979.
l S.
Letter, B&W (J. H. Taylor) to NRC (R. P. Denise), dated December 10, 1979.
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