ML20085N579
| ML20085N579 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/04/1983 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8311110118 | |
| Download: ML20085N579 (4) | |
Text
{{#Wiki_filter:. BALTIM O RE GAS AND ELECTRIC CHARLES CENTER.P. O. BOX 1475 BALTIMORE, MARYLAND 21M3 ARTHUR F.. LUNDVALL. JR, v.cc Pacs ocm SuPPLv November 4,1983 Office of Nuclear Reactor Regulation Attn: Mr. J. R. Miller, Chief Operating Reactors Branch #3 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C. 20555
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit 1 Docket No. 50-317 Seventh Cycle License Application Answers to Question Set 2
REFERENCE:
(A) A. E. Lundvall, Jr. to J. R. Miller letter dated September 1, 1983, Supplement 1 to Seventh Cycle License Application (B) A. E. Lundvall, Jr. to J. R. Miller lettet dated October 14, 1983, Refinements to Zircaloy Growth Correlation for Unit 1 Cycle 7 Gentlemen: The enclosure to this letter provides our response to your second set of questions concerning the reload submitial for Unit 1 Cycle 7 (Reference (A)). This question was verbally received by Baltimore Gas & Electric in a teleconference between Joe Mihaleik dnd Dave Jaffe on October 28,1983. In Reference (B) you were provided a new Zircaloy Growth Correlation. Recent data indicates that release of the correlation was premature. With this letter we are cancelling our Reference (B) submittal and requesting you withdraw it from the Calvert Cliffs Unit 1 Docket No. 50-317. Yours very truly, BALTIMORE GAS & ELE RIC COMPANY w J'94C Enclosure (20 copies) 8311110118 831104 4 yDRADOCK 05000317 PDR Y I 1
O November 4,1983 Mr. J. R. Miller, Chief ec: J. A. Biddison, Esq. (w/o encl) G. F. Trowbridge, Esq. (w/o encl) Mr. D. H. Jaffe, NRC Mr. R. E. Architzel, NRC Mr. R. R. Mills, CE Mr. R. E. Corcoran, DHMH l l-r l i _--m--._m.-._- .__m___ _a u_-__
t NRC QUESTION / RESPONSE Question _ Why is the current fuel modification at Calvert Cliffs Unit 1 necessary?
Response
Prior to their discharge at the end of Cycle 7, the Calvert Cliffs Unit 1 Batch F and G fuel assemblies will accumulate fluences beyond their original design bad's. Although application of the original design correlations for fuel rod and guide tube growth predicted dimension changes at these fluences in excess of what could be accommodated by the assembly design, extensive data collected at Calvert Cliffs on growth behavior (including data at advanced fluences) indicated that margin existed to justify continued use of the Batch F and G fuel assemblies to the expected fluences. It was therefore planned to utilize this more recent Zircaloy length change data to refine the growth correlations and demonstrate ncceptable performance. In addition, measurements were planned to confirm the applicability of the refined cor-relations to the fuel batches expected to receive the highest Cycle 7 ex-posures. As a contingency measure, plans were also made to have parts and equipment available to modify assemblies during the Cycle 6 shutdown in the event of unexpected adverse measurement results. A large number of measurements have now been made on two-cycle Batch G and Batch F fuel, and on three-cycle Batch F fuel. The measurements confirm that the refined guide tube length change correlation accurately predicts the per-formance of the fuel assembly structure. However, the measurements do not confirm that the three-cycle Batch F shoulder gap change is accurately pre-dicted by the use of the revised correlations. .]
\\. The higher shoulder gap change ob erved for the three-cycle Batch F fuel cannot be discounted at this time as being applicable to third-cycle fuel to be used in Cycle 7. These fuel assemblies will receive an exposure higher than that of the three-cycle Batch F assemblies and higher than their design basis. There-fore, it is considered prudent to modify the two-cycle Batch F assemblies and those Batch G assemblies whose gap measurements indicate a potential for gap closure in the third cycle. The assembly modi fication provides additional shoulder gap clearance and is very similar to that performed on ANO-2 Batch C assemblies prior to Cycle 3 operation. As at ANO-2, certain assemblies will not be modified if the combi-nation of observed behavior through two-cycles and the incremental thi rd-cycle fluence produces high confidence of adequate clearance during Cycle 7. JFC:djb F55117-3 i 9 - - -e ek*e dw+m?h e e euw se e w-eeW+= 9 g 4-s:.w w me w
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