ML19339B411
| ML19339B411 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 12/12/1977 |
| From: | Heider L YANKEE ATOMIC ELECTRIC CO. |
| To: | Stello V Office of Nuclear Reactor Regulation |
| References | |
| WYC-77-3, NUDOCS 8011060859 | |
| Download: ML19339B411 (2) | |
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Victor Stello, Jr., Director
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Dear Sir:
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Subject:
Yankee Topical Power Spike Model As discussed with your staff at a November 16, 1977 meeting, Yankee Atomic Electric Company's Nuclear Services Division requests that the NRC review the subject document which is enclosed. An additional 59 copies are being transmitted under separate cover.
The purpose of the power spike model is to evaluate the magnitude of local power peaking which arises because of the increasing neutron flux due to the decrease of neutron absorption, resulting from the for-mation of gaps due to fuel densification. Since the power peaking in a given rod at a given axial interval is a function of the size. and number of gaps in the surrounding fuel rods, the power spike model employs a statistical approach to determine the gap distribution.
Based on this gap distribution and a conservative set of percent contributions to the power peaking due to a single gap, the augmented power distribution is determined. The ratio of the worst augmented power to the worst nominal power is the power spike. The program recomputes the power spike of each axial interval a few thousand times to develop a good statistical sample. Finally, utilizing the power census, the power spike for each axial interval, is determined with 95% confidence that no more than one fuel rod will exceed the power spike.
We would appreciate the expeditious review and approval of this model.
Upon approval we intend to im=ediately request that this model be amended to one of our operating plant dockets.
Very truly yours, YANKEE ATOXIC ELECTRIC COMPANY L
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v L. H. Heider Assistant Vice President REG /kg
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To:
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CATE OF DOCUMENT Yankee Atomic Electric Company 12/12/77 Mr. Victor Stello, Jr.
Westborough, Mass.
cATE RECEivEo L. H. Heider 12/19/77 METTE R 2NOTonIZEO PRCP INPUT FC AM NUMBER CF COPIES RECEIVED R orilGiNAL ZN C LASSIFI E D CCOPY 3 St bM l
- E SC th PTIO N ENCLOSURE Consists of report entitled " Yankee Power Spike Model"- by P. T. Antomopoulos, K. J.
Heider and C. L. Watkins - Nuclear Engineer-ing & Development Dept. - November 1977.....
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