ML20004C567
| ML20004C567 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 05/29/1981 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| References | |
| NUDOCS 8106040284 | |
| Download: ML20004C567 (4) | |
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UEITED STATES
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WASHINGTON. D. C. 20558
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Docket No. 50-368 Mr. William Cavanaugh, III Senior Vice President Energy Supply Department Arkansas Power & Light Company P. O. Box 551 Little Rock, Arkansas 72203
Dear Mr. Cavanaugh:
The Thermal Hydraulics Section of the Core Performance Branch has conducted further review of your ANO-2 Cycle 2' Reload Report and supporting documents and has developed requests for additional information numbered
- 492.72 through 492.77 as set forth in the enclosure.
Please contact us if you have questions regarding the items noted in the enclosure.
Sincerely, obert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
Enclosure:
As stated cc: See next page g.,
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L 8106040284 F
e Arkansas Power & Light Company CC Mr. David C. Trimble Director Criteria and Standards Division Manager, Licensing Office of Radiation Progrart (ANR-460)
Arkansas Power & Light Company U.S. Environmental Protection Agency P. O. Box 551 Washington, D. C.
20460 Little Rock, Arkansas 72203 U.S. Environmental Protection Agency Mr. James P. O'Hanlon Region VI Office General Manager ATTN: EIS COORDINATOR Arkansas Nuclear,ae 1201 Elm Street P. O. Box 608 First International Building Russellville, Arkansas 72801 Dallas, Texas 75270 Mr. Robert B. Borsum Babcock & Wilcox
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Nuclear Power Generation Division Su.ite 420 7735 Old Georgetown Road Director, Bureau of Environmental Bethesda, Maryland 20014 Health Services 4815 West Markham Street
' Nick' Reynol ds Little Rock, Arkansas 72201 c/o DeBevoise & Liberman -
1200 Seventeenth Street, N.W.
Washington, D. C.
20036 Ar'<ansas Polytechnic College Russellville, Arkansas 72801 Honorable Ermil Grant Acting County Judge of Pope County Pope County Courthouse Russellville, Arkansas 72801 Mr. Charles B. Brinkman
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Manager - Washington Nuclear Operations C-E Power Systems 4853 Cc' dell Avenue, Suite A-1 r
Bethesda, Maryland 20014 4
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a Enclosure i
492.72 In response to the question 492.62, the initial conditions for both of the events (loss of flow a should include the initial power levelnd CEA withdrawal) radial and axial peaking factors and peak linear heat rate of the hot pin.
Please provide this information for ANO-2 Cycle 1 and Cycle 2.
Briefly describe the changes in values.
Is the sJ acted case representative of worst case operating conditions for core life? If so, describe how this case was chosen; if not, why not?
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492.73 There is a discrepancy between the CPC algorithm and the CETOP-D topical in the two-phase friction factor multiplier.
For pressure below 1850 psia, f2 (P. G) is used for the multiplier with mass velocity G > 0.7 x 105 lb/hr-ft2 as described in the CETOP-D topical 7 whereas f3 (P. G) is used in the CPC algorithm.
Please clarify the discrepancy.
492.74 For single-phase friction factor, the CPC uses Blasius correlation, F = 0.184 Re 0*2, which seems to assume smooth '.
surface. What is the value of surface roughness for the ANO-9 2 fuel cladding? How mch difference in friction factor is it compared to tile Moody friction factor, using the correct relative surface roughness?
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492.75 In your response to question 492.3, the pressure transport coefficient, Np, is 2.3 for CETOP-2. However, the CEN-143 report indicates the transport coefficient CN, defined as CN = (No. of gaps)/Np, equal to'O.15.
Please explain as to how many. channel gaps and how they are obtained in the CPC
, four-channel modeling. How does the CDC modeling differ from the CETOP-D core thermal design modeling?
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492.76 The response to question 492.62 indicates that, using the COSM0/W-3 methodology for the ANO-2 Cycle 2 core, the esti-mated minimum DNBR for loss of flow and CEA withdrawai transients with initial power level of 103 percent rated power are 1.115 and 1.121, respectively.
These values are well below the allowable DNBR limit of 1.3 for the W-3 correlation and infer that Cycle 2 and later power distri-butions were not fully considered in the FSAR analyses of these events.
Explain and justify the ad metnods for selection of bounding cases. gquacy of your Are the Cycle 2 analyses representative of Cycle 2 only? If so, is there any assurance that this reactor can operate at the licensed power level without excessive DNB trips throughout future cycles without further revisions to design methodology in order to achieve more thermal margin?
492.77 Your response to question 492.60 is not complete. As indi-cated, there are chances when minimum DNBR might occur on channels other than a guide-tube channel.
In these cases, the question is not only whether CETCP is more conservative than TORC. Rather, the concern is whether it is legitimate to use guide-tube channel mot Mng to represent other types of channels.
If the guide-tt.be channel is to be used entirely, then it is necessary to prov9 that minimum DNBR never occurs ir. other types of channel throughout the core life. Otherwise, it must be shown that the guide-tube channel modeling using CETOP always predicts the same or lower DNBR than is predictd for the other chandeli~u~ sing TORC.
Please be specific and quantitative on your proof.
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MAY 2 61081
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