ML20236K448
| ML20236K448 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 07/06/1998 |
| From: | Michael Webb NRC (Affiliation Not Assigned) |
| To: | Meisner M Maine Yankee |
| References | |
| TAC-MA0659, TAC-MA0660, TAC-MA659, TAC-MA660, NUDOCS 9807090321 | |
| Download: ML20236K448 (7) | |
Text
Mr. Michael J. Maisn:r, President July 6, 1998 Mains Yankt,e Atomic Power Company P.O. Box 408 Wiscasset, Maine 04578
SUBJECT:
THIRD REQUEST FOR ADDITIONAL INFORMATION FOR EXEMPTION FROM FINANCIAL PROTECTION REQUIREMENT LIMITS (TAC NOS. MA0659 AND MA0660)
Dear Mr. Meisner:
We are continuing our review of your proposed exemptions to certain insurance coverage and financial protection requirement limits of 10 CFR 50.54(w) and 10 CFR 140.11, as detailed in your letter to us dated January 20,1998, as supplemented on June 18, and June 25,1998. However, in order for us to complete our evaluation of the spent fuel heatup analysis that you conducted to determine the time at which the Maine Yankee fuel would not exceed 565"C should the spent fuel pool be drained of all water, we require additionalinformation as specified in the enclosed enclosure. This request affects nine or fewer respondents and therefore, is not subject to Office of Management and budget review under P.L.96-511.
If you have any questions regarding this requeet, please contact me et (301) 415-1347.
Sincerely, ORIGINAL SIGNED BY:
Michael K. Webb, Project Manager Non-Power Reactors and Decommissioning Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No. 50-309
Enclosure:
As stated cc w/ enclosure: See next page k
DISTRIBUTION:
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UNITED STATES J
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NUCLEAR REGULATORY COMMISSION
'f WASHINGTON. D.C. 20556-0001
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July 6, 1998 l
Mr. Michael J. Meisner, President Maine Yankee Atomic Power Company P.O. Box 408 Wiscasset, Maine 04578
SUBJECT:
THIRD REQUEST FOR ADDITIONAL INFORMATION FOR EXEMPTION FROM FINANCIAL PROTECTION REQUIREMENT LIMITS (TAC NOS. MA0659 AND MA0660)
Dear Mr. Meisner:
We are continuing our review of your proposed exemptions to certain insurance coverage and financial protection requirement limits of 10 CFR 50.54(w) and 10 CFR 140.11, as detailed in your letter to us dated January 20,1998, as supplemented on June 18, and June 25,1998. However, in order for us to complete our evaluation of the spent fuel heatup analysis that you conducted to determine the time at which the Maine Yankee fuel would not exceed 565*C should the spent fuel pool be drained of all water, we require additionalinformation as specified in the enclosed enclosure. This request affects nine or I
fewer respondents and therefore, is not subject to Office of Management and budget review under P.L.96-511.
1 If you have any questions regarding this request, please contact me at (301) 415-1347.
Sincerely, 1
? %L~f W b] O l
Michael K. Webb, Project Manager Non-Power Reactors and Decommissioning l
Project Directorate l
Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No. 50-309 Enclosure..As stated I
cc w/ enclosure: See next page
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' Maine Yankee Atomic Power Station Docket No. 50-309 cc:
Mr. Charles B. Brinkman Friends of the Coast Manager - Washington Nuclear P.O. Box 98
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Operations Edgecomb, ME 04556 j.
' ABB Combustion Engineering i
12300 Twinbrook Parkway, Suite 330 Mr. William O' Dell Rockville, MD 20852 Operations Director
' Maine Yankee Atomic Power Company
-Thomas G. Dignan, Jr.' Esquire P.O. Box 408 Ropes & Gray-Wiscasset, ME 04578
)
L One International Place Boston, MA- 02110-2624 Mr. George Zinke, Director Nuclear Safety and Regulatory Affairs j
Mr. Uldis Vanags Maine Yankee Atomic Power Company
' State Nuclear Safety Advisor P.O. Box 408 State Planning Office
- Wiscasset, ME 04578-State House Station #38 Augusta, ME 04333 Mr. Jonathan M. Block Attorney at Law Mr. P. L. Anderson, Project Manager
- P.O. Box 566 Yankee Atomic Electric Company Putney, VT 05346-0566 580 Main Street l'
' Bolton, MA- 01740-1398
- Mr. Michael J. Meisner, President Main Yankee Atomic Power Company Regional Administrator,' Region i P.O. Box 408 U.S. Nuclear Regulatory Commission Wiscasset, ME 04578 475 Allendale Road King of Prussia, PA 19406 Mr. Robert Fraser, Director l
Engineering First Selectman of Wiscasset
. Maine Yankee Atomic Power Company l
Municipal Building P.O. Box 408 U.S. Route 1 Wiscasset, ME 04578 Wiscasset, ME 04578 Mr. Patrick J. Dostie l
Mr. Richard Rasmussen State of Maine Nuclear Safety
' Senior Resident inspector inspector Maine Yankee Atomic Power Company Maine Yankee Atomic Power Company U.S. Nuclear Regulatory Commission-P.O. Box 408 P.O. Box E Wiscasset, ME 04578
. Wiscasset,' ME 04578 Mr. Mark Ferri
- Mary Ann Lynch, Esquire Decommissioning Director
. P.O. Box 408 P.O. Box 408 Wiscasset, ME 04578 Wiscasset, ME 04578
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ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION 1
l BY THE OFFICE OF NUCLEAR REACTOR REGULATION ASSESSMENT OF THE LOSS OF WATER FROM THE SPENT FUEL POOL AT MAINE YANKEE ATOMIC POWER STATION I
On May 15,1998, Maine Yankee Atomic Power Company (MY) submitted an analysis performed by their contractor, Scientech Inc., to determine the time at which the fuel cladding temperature would not exceed 565'C following a complete loss of water in the spent fuel pool. MY and Scientech also met with the NRC staff on June 9,1998, to l
discuss their submittal. Following the meeting, in a letter dated June 15,1998, the NRC staff issued a request for additionalinformation (RAl) to support the conclusions of the submittal. MY responded to this RAI by letter dated June 18,1998. MY subsequently provided additional information to the staff by letter dated June 25,1998. This RAI l
identifies the specific initial NRC requests, the revised NRC request, and a discussion of the basis for the staff's RAI to complete its evaluation of the original requested information.
- 1. Initial NRC request: The information submitted by MY does not contain sufficient information about the building temperature during the scenario being analyzed. Provide your building temperature analysis.
Revised NRC request: Provide a revised building heat transfer calculation that includes the total building thermal renstance and the convective heat removal by the ventilation system.
Basis for the revised request: MY provided a building temperature analysis performed by Scientech in Attachment A of their June 18,1998, submittal. The information submitted in Attachment A does not contain an adequate building temperature analysis for the case of an empty spent fuel pool. MY provided a Scientech MELCOR calculation in responding to this request. The MELCOR analysis is an evaluation of the building temperature with water in the spent fuel pool, and therefore, is not applicable to the case with any water in the pool. In a telephone call of June 23,1998, the staff indicated that MY needed to provide a building temperature calculation with no water in the spent fuel pool.
In response to the June 23,1998, discussion, MY submitted a new building temperature calculation dated June 25, entitled, "Simolified Assessment of Fuel Buildino Environment Temperatures Followina Total Loss of Water in the Soent Fuel Pool." This calculation contains several errors. The specific errors in the heat and mass balance equations from pages 3 and 4 of 8 are described in the following paragraphs. Equations 1 through 5 refers to the numbered equations on pages 3 and 4 of the MY submittal.
t Equation 1: Based on the definitions for equations 4 and 5 the heat balance equation is incorrect.
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1 Equation 2: The decay heat based on your SFP measurements is not acceptable, See the discussions below on the decay heat measurements.
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Equation 3: The heat transfer coefficient is incorrect. MY must account for the entire thermal resistance which includes the inside convective heat transfer, the j
conduction heat transfer, and the external convective heat transfer. Based on earlier information provided by MY it appears that the thermal resistance is dominated by the conduction through the insulation. The composite convective heat transfer coefficient calculated in Attachment A on page 6 of 8 is also incorrect based on the vertical and horizontal heat transfer coefficients listed for the I
calculated building temperature. The composite heat transfer coefficient can never i
be greater than the maximum of the two heat transfer coefficients for the parallel
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paths. The MY Biot number analysis on page 7 of 8 is not relevant to steady state energy balances. It only pertains to the use of lumped parameter analysis in transient heat transfer calculations.
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Equations 4 and 5: The right-hand side of equation 4 and the first term on the right-hand side of the equation 5 constitute a double accounting of the energy I
needed to heat the air from outside to the building temperature, in second and third terms on the right-hand side of the equation 5 you are treating the water in the air as liquid instead of water vapor. The water in the air is already vapor, and therefore, you cannot account for the energy it takes to heat the water up to 212 'F and the heat of vaporization. You can take credit for the higher heat i
capacity of water vapor compared with air similar to the treatment of the air in i
equation 4.
L The values for the density in the Property Table on page 4 of the calculation appear to be incorrect. Based on the values in the table, it appears that MY may have used temperature values in Fahrenheit instead of Rankine (absolute temperature) in an ideal gas calculation.
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- 2. !nitial NRC request: The information submitted by MY does not contain sufficient j
information about the basis for the decay heat used in your analysis. Provide the i
supporag information for your decay heat values. This should include detailed information abor your' experimental measurements and the method used to reduce the data. Compare i
the aecay heat used by MY to the current ANS decay heat standard and describe your treatment of uncertainties.
l Revised NRC request: Provide further justifications that demonstrate that decay heat values are calculated using a method that gives conservative decay powers for the fue!
l operating history and decay times for both the overall pool power and the hot bundia i
power.
Basis for the revised request: The MY response does not provide adequate justification for use of the experimentally determincd decay heat. MY did not analyze the measurement and data reduction uncertainties for their spent fuel pool decay heat measurements. The temperature measurements alone have an uncertainty that is larger than the pool l
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temperature difference that was used to calculate the decay power. Other sources of uncertainty must also be considered in an overall uncertainty analysis, it is also apparent from the MY analysis that the power in the high power bundle used by Scientech is decaying at much faster rate than the total pool power. Therefore, a measurement of the overall pool power is not representative of the high power bundle.
- 3. Initial NRC request: The information submitted by MY does not contain sufficient information about the adequacy of TRAC for the analysis. Provide information that demonstrates that the models contained in TRAC (including heat transfer and wall drag correlations) are adequate for the geometry and conditions that are being analyzed. include any information about code assessment applicable to the conditions for which MY is using the code.
Revised NRC request: Provide information showing that the heat transfer coefficients predicted by TRAC are appropriate for the flow and temperature conditions in the calculation.
Basis for revised request: The information provided by MY does not demonstrate that TRAC is adequate to perform the analysis. TRAC is being used to perform an analysis that is untypical of the wide assessment basis that has been quoted for TRAC. The burden is on the user to demonstrate that individual models are applicable for the specific situation (scenario, conditions, and geometry) they are modeling. None of the code assessment cited is applicable to the MY use of TRAC. Citing the number of control volumes used as being equal to the number used in one assessment problem gives erroneous conclusions since the test bundle was only one-third the length of an actual fuel bundle. The o.nly relevant information provided is the absolute value of the heat transfer coefficient and the approximate gas velocity. These values also have little meaning unless presented in terms of parameters that affect heat transfer such as Reynolds number, Nusselt number, Prandtl D
number, and Grashof number and compared to relevant experimental data or assessed l
literature correlations. The hand calculation of average cladding temperature does not account for the rise in gas temperature as it moves up the bundle and greatly underestimates the average cladding temperature. The value quoted for the TRAC average cladding temperature appears to be the peak temperature based on the plots from the Scientech analysis presented and submitted to the NRC.
- 4. Initial NRC request: The information submitted by MY does not contain sufficient information about the adequacy of the modeling approach used in the analysis. Provide information showing that the additive forrn loss coefficients used in the analysis are appropriate for the geometry and flow conditions present in the analysis. Also provide information showing that the single hot channel modeling results are conservative compared to an approach that would include parallel flow paths through lower powered bundles.
Revised NRC request: Provide information to show that the loss coefficients are applicable or conservative for the geometry and Reynolds numbers applicable to the MY analysis.
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4 Basis for additional request: Contrary to the MY response that loss coefficients depend only on geometry, form loss coefficients do depend on Reynolds number in addition to l
geometry. The effect can be significant at low values of the Reynolds number which are representative of the flow conditions in this problem. This dependence can be found for a wide range of geometries in the book " Handbook of Hydraulic Resistance," by I. E. Idelchik and M.O. Steinberg.
- 5. Initial NRC request: Provide a discussion of the available margin determined by the analysis and an estimate of the calculation uncertainties.
' Revised NRC request: Provide a revised discussion of the available margin determined by l-the analysis and an estimate of the calculation uncertainties. Uncertainties and l
conservatism should be quantified.
Basis for additional request: Some of the stated conservatism is incorrect. In particular the building atmosphere assumption of 200*F will probably be shown to be nonconservative and the decay heat in the limiting bundle is nonconservative compared to ANS decay heat l
standards. Since the bundle power was not measured, this is a nonconservative assumption. There was no accounting for experimental uncertainty in the SFP decay heat measurements.
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