ML20058P203
| ML20058P203 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 12/16/1993 |
| From: | De Agazio A Office of Nuclear Reactor Regulation |
| To: | Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| References | |
| TAC-M86958, NUDOCS 9312230141 | |
| Download: ML20058P203 (7) | |
Text
1 I
December 16, 1993 Docket No. 50-443 i
Serial No. SEA-93-031 Mr. Ted C. Feigenbaum i
Senior Vice President and Chief Nuclear Officer i
North Atlantic Energy Service Corporation Post Office Box 300 l
Seabrook, New Hampshire 03874
Dear Mr. Feigenbaum:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (TAC M86958)
We have performed a partial review of Yankee Atomic Electric Company < Topical i
Report YAEC-1849P, Thermal Hydraulic Analysis Methodology Using VIPRE-01 for i
PWR Applications. The methodology is based upon use of the COBRA code which has been approved by the NRC. However, to complete our review, we require f urther information and clarifications as identified in the enclosure-to this letter. To avoid impacting the review schedule, you should submit your respanse no later than January 5, 1993.
The requirements of this letter affect fewer than 10 respondents, and therefore, are not subject to Office of Management and Budget review under P.L.96-511.
Sincerely, e
Original signed by:
Albert W. De Agazio, Sr. Project Manager Project Directorate I-4 Division of Reactor Projects - I/II Otfice of Nuclear Reactor Regulation
Enclosure:
As stated cc w/ enclosure:
See next page i
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DISTRIBUTION:
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\\j Document Name: G\\DEAGAZIO\\86958.RAI l-
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December 16, 1993 i
Docket No. 50-443 j
Serial No. SEA-93-031 i
Mr. Ted C. Feigenbaum j
Senior Vice President and Chief-Nuclear Officer North Atlantic Energy Service Corporation Post Office Box 300 Seabrook, New Hampshire 03874 j
Dear Mr. Feigenbaum:
j
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (TAC M86958) e We have performed a partial review of Yankes Atcmic Electric Company Topical Report YAEC-1849P, Thermal Hydraulic Analysis Methodology Using VIPRE-01 for PWR Applications. The methodology is based upon use of the COBRA code which has.been approved by the NRC. However, to complete our review, we require l
further information and clarifications as identified in the enclosure to this letter. To avoid impacting the review schedule, you should submit your_
j response no later than January 5, 1993.
The requirements of this letter affect fewer than 10 respondents, and therefore, are not subject to Office of Management and Budget review under P.L.96-511.
.i Sincerely, j
Original signed by:
a Albert W. De Agazio, Sr. Project Manager Project Directorate I-4 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation j
Enclosure:
1 As stated _
cc w/ enclosure:
See next page
=
l DISTRIBUTION:
t Docket File JCalvo OGC RJones j
NRC & Local PDRs SNorris ACRS (10)
Llois.
SYarga ADe Agazio JRogge, RGI MCaruso j
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December 16, 1993 Docket No. 50-443 Serial No. SEA-93-031
-l i
Mr. Ted C. Feigenbaum Senior Vice President and Chief Nuclear Officer North Atlantic Energy Service Corporation Post Office Box 300 M
.Seabrook,_New Hampshire 03874
Dear Mr. Feigenbaum:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (TAC M86958)
We have performed ~ a partial review of Yankee Atomic Electric Company Topical, Report YAEC-1849P, Thermal Hydraulic Analysis Methodology Using VIPRE-01 for-
~
PWR Applications. The methodology is based upon use of the COBRA code which has been approved by the NRC. However, to complete our_ review, we' require' l
further information and clarifications as identified in the enclosure to this-t
-letter. To avoid impacting the review schedule,' you should' submit your-response no later than January 5,1993.
The requirements of this letter affect fewer than 10 respondents, and' a
therefore, are not subject to Office of Management and Budget review under P.L.96-511.
i Sincerely, l
/
.i Albert W. De Agazio, Sr.
r ject Manager-Project Directorate I.;
Division of Reactor Projects - I/II Office of Nuclear Reactor. Regulation h
- ~
Enclosure:
As, stated t
o cc w/ enclosure:
-See next page
.)
t i
t l
i
Mr. Ted C. Feigenbaum Seabrook Station-CC*
i
' Thomas Dignan, Esq.
Mr. George L. Iverson, Director
.i
. John.A. Ritsher, Esq.
New Hampshire Office of Emergency Ropes and. Gray' Management One International Place State Office Park South Boston, Massachusetts 02110-2624 107 Pleasant Street-Concord, New Hampshire 03301 i
Mr. Peter Brann Assistant Attorney General Regional Administrator, Region I State House, Station #6 U.S. Nuclear Regulatory Commmission Augusta, Maine 04333 475 Allendale Road King of Prussia, Pennsylvania 19406 Resident Inspector U.S. Nuclear. Regulatory Commission Office of the Attorney General Seabrook Nuclear Power Station One Ashburton Place Post Office Box 1149 20th Floor I
Seabrook, New Hampshire-03874 Boston, Massachusetts 02108.
Jane Spector Board.of Selectmen Federal Energy Regulatory Commission Town of Amesbury 825 North Capital Street, N.E.
Town Hall Room 8105 Amesbury, Massachusetts 01913 Washington, DC 20426 Mr.- Jack Dolan i
Federal' Emergency Management Agency.
Mr. T. L. Harpster -
Region I North Atlantic Energy Service J.W. McCormack Post Office &-
Corporation Courthouse Building, Room 442.
i Post Office Box 300 Boston,-Massachusetts 02109.
Seabrook, New Hampshire 03874 Mr. David Rodham, Director Massachusetts Civil Defense Agency Town of Exeter 400 Worcester Road 10 Front Street Post Office Box 1496 Exeter, New Hampshire 03823 Framingham, Massachusetts 01701-0317..
ATTN: James Muckerheide l
Gerald Garfield, Esq.
Day, Berry and Howard Jeffrey Howard, Attorney General i
L City Place G. Dana Bisbee, Deputy Attorney-Hartford, Connecticut 06103-3499 General-i Attorney General's Office Mr. R. M. Kacich 25 Capitol Street
- Nor,theast Utilities Service Company Concord, New Hampshire 03301 Post Office Box 270 1
Hartford, Connecticut 06141-0270 Mr. Robert Sweeney.
Bethesda Licensing Office Suite 610 3 Metro Center Bethesda, Maryland 20814 4
ATTACHMENT Request for Additional Information Review of YAEC-1849P Although COBRA and VIPRE are similar codes, there are differences and the codes therefore do not produce identical results.
While the methodology developed with COBRA may provide useful guidance for development _ of an analytical methodology using VIPRE, YAEC should not assume that the approved methodology can be directly-transferred to VIPRE without qualification.
In-general, qualification of models and demonstration of conservative approaches should be provided for the methodology using VIPRE in response to the VIPRE SER requirements.
VIPRE Methodology:
1.
The SERs on YAEC-1296P and VIPRE-01 require that YAEC must demonstrate that the same DNB correlation limit is applicable with VIPRE for Maine Yankee by demonstrating that the YAEC-1/VIPRE combination yields more conservative results as YAEC-1/ COBRA-IIIC.
2 The range of applicability for the RCS pressure with YAEC-1 and W-3 does not cover the lower range of system pressure such as experienced during a steam line break-event.
Discuss those CHF correlations which YAEC intends to use for that pressure range and the corresponding DNBR safety limit.
3.
The use of the direct solution method is not applicable in certain situations described in the VIPRE manuals.
Provide assurances that these situations are not encountered in any of the transient analyses for which YAEC intends to use VIPRE.
4.
Has YAEC modified (besides adding CHF correlations) VIPRE-01 for use to analyze Yankee, Maine Yankee and Seabrook?
If so, describe and-qualify each modification.
Demonstration Analyses:
5.
In the comparative cases for Main Yankee, the limiting CHF location predicted by VIPRE occurred in the channel next to an unheated CEA guide tube in three of _ thirty cases, differing from. COBRA predictions. Discuss the sources of this result and-justify it.
6.
Provide the power shapes and peaking factors used in cases 5 through 30.
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7.
In the Seabrook comparative cases, YAEC presented two transient cases for the same loss of flow transient.
Comparing the results from these two cases, Cases 3 and-4, when the transient core power, flow and pressure were used as forced functions, the VIP _RE predicted MDNBR was less than 1.3, the correlation limit (Case 4) whereas when the heat flux and flow were used as forcing functio., the VIPRE -
predicted MDNBR was above 1.3.
How do VIPRE results compare against THINC-IV results?
8.
All comparisons provided in Chapter 4 of the Topical Report were performed in a steady-state mode except for one case for Seabrook.
Provide transient calculations for Chapter 15-type transients and
- compare, analyze and justify the predictions vis-a-vis the corresponding FSAR results for each plant.
DNBR Limits for Seabrook:
9.
Provide the comparable M/P data for THINC/WRB-1 shown on Table C.I.2.
10.
The combination of correlations selected on Table 3.3.1 is different from that normally selected by other users.
Justify that this combination results in conservative prediction by providing results from sensitivity studies in which other correlations are used.
11.
Justify the use of the turbulent mixing models for all three plants.
(see also Appendix B) 12.
Justify the size of core channel model used.
Plant Specific VIPRE Model Description 13.
Describe and justify the DNB methodology for analysis of steam line break events.
This should include the core nodalization, peaking factors used, and expected system parameter trends.
14.
Justify the use of the gap conductance indicated on Table B.I.3.
Revised Thermal Design Procedure Application for Seabrook s
, 15.
Explain and justify how the RTDP is determined for Seabrook with the old methodology and how the proposed new limit differs.
Is the methodology described in the topical report the same as that used to generate the current value and only the code is different?
16.
Explain why the uncertainty associated with the effective flow fraction is assumed to be uniformly distributed rather. than in a accordance with a normal distribution function.
2
t l
17.
Identify the version of VIPRE used.
If the earlier version of VIPRE-01 was used, YAEC should quantify the impact of errors in the code to compute thermal conductivity of zircaloy.
Then YAEC should justify'the uncertainties used for computer codes.
18.
Discuss thoroughly how "the maximum change.in the VIPRE-01 calculated MDNBR (was determined) for a' 1% change within the intended applicability range".
Provide a table with the final 1%
changes for the RTDP parameters which resulted in the maximum change in the VIPRE-01 calculated MDNBR.
Explain thoroughly how YAEC's method to compute sensitivity factors is different from either ITDP and RTDP.
19.
Explain what is meant by <2.0 for the lower range limit for the heat generation rate factor.
In addition, justify the low limit for the coolant flow and the core outlet pressure.
20.
How is the RTDP determined for Seabrook under the current methodology and how is the proposed limit differ from the current value.
21.
Discuss the additional cycle-dependant penalties (description and values) to be added to the computed RTDP DNBR limit for use in the safety analysis and the resulting final safety analysis DNBR limits.
22.
Explain how the cases on Table C.2.4 were selected.
In addition, i
explain the reasons (and significance of) the fact that the actual VIPRE-01 ratios are all very close to each other while the ratios obtained using the sensitivity factors are different.
23.
Explain clearly.how Table C.2.5 was generated and how this shows the linearity assumption.
I p
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