ML20212H183
| ML20212H183 | |
| Person / Time | |
|---|---|
| Issue date: | 09/28/1999 |
| From: | Kalyanam N NRC (Affiliation Not Assigned) |
| To: | Mallay J SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER |
| References | |
| PROJECT-702 TAC-MA4593, NUDOCS 9909300236 | |
| Download: ML20212H183 (6) | |
Text
.... -..:
September 28, 1999 Mr. James F. Mallay -
Director, Nuclear Regulatory Affairs -
Siemens Power Corporation 2101 Horn Rapids Road Richland, WA 99352'
SUBJECT:
' REQUEST FOR ' ADDITIONAL INFORMATION - SIEMENS TOPICAL REPORT, EMF-92-081 REVISION 1, " STATISTICAL SETPOINT/ TRANSIENT METHODOLOGY FOR WESTINGHOUSE REACTORS" (TAC NO. MA4593)
Dear Mr. Mallay:
By let'.ar dated December 21,1998, the Siemens Power Corporation submitted Topical Report EMF-92-081, " Statistical Setpoint/ Transient Methodology for Westinghouse Reactors" for staff review. The staff is reviewing the Topical Report and additional information, as discussed in the enclosure is requested, in order for the staff to complete its review.
The enclosed request was discussed with your staff on September 22,1999. A mutually agreeable target date of within 30 days of the date of this letter for your response was
' established. If circumstances result in the need to revise the target date, please call me at the
- earliest opportunity at 301-415-1480.
Sincerely, ORIG. SIGNED BY N. Kalyanam, Project Manager, Section 2 Project Directorate IV & Decommissioning 6!PA FiU" RRd@,,1q h Fce o"f Nuclear Reactor Regulation
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t WASHINGTON, D.c. 20555 4001 49.....,o September 28, 1999 Mr. James F. Mallay Director, Nuclear Regulatory Affairs Siemens Power Corporation 2101 Horn Rapids Road Richland, WA 99352
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - SIEMENS TOPICAL REPORT, EMF-92 081 REVISION 1, " STATISTICAL SETPOINT/ TRANSIENT METHODOLOGY FOR WESTINGHOUSE REACTORS" (TAC NO. MA4593)
Dear Mr. Mallay:
By letter dated December 21,1998, the Siemens Power Corporation submitted Topical Report EMF-92-081, " Statistical Setpoint/ Transient Methodology for Westinghouse Reactors" for staff review. The staff is reviewing the Topical Report and additional information, as discussed in the enclosure, is requested in order for the staff to complete its review.
The enclosed request was discussed with your staff on September 22,1999. A mutually agreeable target date of within 30 days of the date of this letter for your response was established. If circumstances result in the need to revise the target date, please call me at the earliest opportunity at 301-415-1480.
Sincerely, ce l
N. Kalyanam, Pr ect Manager, Section 2 l
Project Directorate IV & Decommissioning Division of Licensing Project Management Office of Nuclear Reactor Regulation Project No. 702 l
Enclosure:
Request for Additional Information l
i t
GENERAL QUESTIONS PERTAINING TO BOTH THE WESTINGHOUSE AND COMBUSTION ENGINEERING STATISTICAL SETPOINT/ TRANSIENT METHODOLOGY 1.
Please provide flowcharts of overall methodology for arriving at the statistical setpoint/ transient analysis.
2.
Please confirm the use of textbook statistical methods throughout.
3.
Please explain if the applied methodology is in accordance with the methodology described in GSUAM.
4.
Please provide details on why the methodologies for the two reactor types differs.
l Enclosure i
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STATISTICAL SETPOINT/ TRANSIENT METHODOLOGY FOR l
WESTINGHOUSE TYPE REACTORS l
REQUEST FOR ADDITIONAL INFORMATION 1.
Paae 2-3. eauation it is stated that K, becomes the adjustment for the nonlinear relationship between power and delta T. Please describe how K. provides the adjustment for nonlinear relationship and explain if the coefficient is calculated at each state point or if one value of the coefficient is determined.
2.
Paae 2-5. first paraaraoh Please define the parameters which feed into the peaking measurement uncertainty and engineering tolerance factors.
3.
Paae 2-7. Section 2.4 l
Please describe the situation where the design value for the peaking can be exceeded l
and explain why the design value can be exceeded.
l 4.
Paae 2-9. last caracraoh Please provide additional details on how the probability density for delta measurement is converted into a probability density in the reset function.
5.
Paae 2-10. Section 2.5 It is stated that the dynamic compensation term is confirmed by transient analysis.
Please describe the transient analysis performed to confirm the compensation term.
l 6.
Paae 2-11. fourth oaraaraoh it is stated that in the confirmation of the OPAT, a scan is performed tc locate the
(
minimum margin. Please describe how the scan is performed and if a raatrix of the parameters used in the scan is generated, please provide it.
i
' 7.
Paae 2-12. Section 2.6.2 Please explain (provide technical justification) how the scaling of the fuel centerline melt power is performed. Additionally, please explain how the peaking and engineering uncertainties were evaluated.
r
. 8.
Paae 2-13. first caraaraoh Please provide details on how the trip channel uncertainty was obtained.
9.
Paae 2-14. last paraaraoh -
Two methods of including the delta i uncertainty are described. Please provide details on which method is used in this analysis. Also, please provide details on what the bounding approximation is when it is used in calculations.
10.
Paae 3-1. last paraaraoh The last sentence on the page references XCOBRA-lllC. Please provide a reference for this approval and details of the uses this code was approved to perform.
- 11.
Paae 3-7. third oaraaraoh it is stated that a less conservative approach may be used if the conservatism resulting from the most sensitive point is unacceptably large. Please provide the definition of unacceptably large. Also, please quantify the frequency of the most sensitive point resulting in an unacceptably large conservatism.
12.
Paae 3-9. fourth oaraaraoh it is stated that in some cases the' deterministic adjustment can be used instead of the statistical adjustment. Please provide additional details on the necessary criteria for using the deterministic method and quantify how frequently the deterministic adjustment is used. Since the statistical adjustment is the bounding adjustment, demonstrate how SPC ensures that using the deterministic adjustment will not violate the 95/95 confidence limit for avoiding DNB.
13.
Pace 3-18. fourth paraaraoh
- it is stated that the hot leg saturation is no analog to the response surface uncertainties.
Piease explain what this statement means.
14.
Pace 4-3/4-4. last caraaraoh continuina onto the next oaoe it is stated that the 95/95 confidence uncertainty-adjusted trip is determined from the probability distribution described in the preceding paragraphs or taken from the Monte Carlo run. Please provide additional details or demonstrate when each method is used.
F1:
. 15.
Pace 4-4. last paraaraoh Please present both methods of calculating the response surface; the method presented on page 4-4 and the more conservative (stated as unnecessary conservative assumption) method mentioned. 'Also, please explain how the more conservative method is unnecessary.
16.
Paae 4-5. second oaraaraoh It is stated that a set of nominal trips is selected for evaluation of the probability density based on each trip. Please explain how the set of nominal trips is selected.
i 17.
Paae 4-5. fourth oaraaraoh it is stated that to confirm the margin to DNB, the experimental design can vary the system parameters, trips, and LCOs. Please provide additional details.
18.
Pace 4-13. third paraaraoh It is stated that the probability of having no margin to DNB is about 1.86 percent and therefore, no fuel failure by DNB is predicted. Please explain or demonstrate the J
calculation for this probability.
I 19.
Paae B-19. Fiaure B.8 Please explain the method used to generate this figure.
1 i
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