ML20205J331
| ML20205J331 | |
| Person / Time | |
|---|---|
| Issue date: | 04/05/1999 |
| From: | Wang E NRC (Affiliation Not Assigned) |
| To: | Mallay J SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER |
| References | |
| PROJECT-702 TAC-MA3457, NUDOCS 9904090315 | |
| Download: ML20205J331 (4) | |
Text
.
patco ft UNITED STATES ye 2
)*'
E NUCLEAR REGULATORY COMMISSION
-f WASHINGTON, D.C. 20555-0001
/
April 5, 1999 Mr. James Mallay, Director I
Regulatory Affairs Siemens Power Corporation 2101 Horn Rapids Road Richland, WA 99352-0130
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) TO THE TOPICAL REPORT EMF-2087(P), REVISION 0, "SEM/PWR-93: ECCS l
EVALUATION MODEL FOR PWR LBLOCA APPLICAT(ONS" (TAC NO. MA3457)
REFERENCE:
Topical Report, EMF-2087, Revision 0, "SEM/PWR-08 ECCS Evaluation Model For PWR LBLOCA Applications"(SPC), August 1998
Dear Mr. Ma? lay:
The U.S. Nuclear Regulatory Commission (NRC) Reactor Sy,tems Branch (SRXB) staff has determined that it needs additionalinformation in order to complete its review of the Siemens Topical Report, EMF-7087, Revision 0, "SEM/PWR-98: ECCS Evaluation Model For PWR LBLOCA Applications" The staff has reviewed the topical report and prepared the attached request for adcitionalinformation for clarification of the approaches used.
l During a telephone conversatien with your staff, Jerry L. Holm, on April 1,1999, we discussed i
the questions contained in this RAI and agreed that your response to this RAI will be provided to the NRC staff on or before April 16,1999.
You have request.ed that portions of the information, EMF-2087, Revision 0, "SEM/PWR-98:
ECCG Evaluation Model For PWR LBLOCA Applications," submitted in August,1998 be exempt from mandatory public disclosure. While the staff has not completed its review of your request in accordance with the requirements of 10 CFR 2.790, that portion of the submitted information is being withheld from public disclosure pending the staff's final determination. The staff concludes that these questions and comments do not contain those portions of the information for which exemption is sought. However, the staff will withhold this letter from public disclosure for 30 calendar days from the date of this letter to allow Siemens the opportunity to verify the staff's conclusions. If, after that time, you do not request that all or portions of the inform 3 tion in the encicsures be withheld from public disclosure in accordance with 10 CFR 2.790, this letter will be placed in the NRC Public Document Room.
j I
Db g4gog gg C
~
- 'e
'b Mr. '. Mallay J These questions affect nine or fewer respondents, and therefore are not subject to review by the Office of Management and Budget under P.L.96-511.
l l
l Should you need to change the schedule in responding this RAI or if you have any questions j
regarding this matter, please contact me at (301) 415-1076.
J i
1 Sincerely, i
" Original Signed By" t
Egan Y. Wang, Reactor Eng:neer Generic Issue and Regulatory improvements Section Generic issue and Environmental Projects Branch Division of Regulatory improvement Prograrns Office of Nuclear Reactor Regulation l
Enclosure:
as stated Project No. 702 i
i DISTRIBUTION:
- Enclosure to be held for 30 days E*Pbblic37 PGEB R/F FAkstulewicz CCarpenter EWang JStaudenmeier RLandry JWermiel RCaruso DMatthews SLWu LOCUMENT NAME: 990401. emf-2087.rai To receive a copy of this document, indicate in the box:
"C" = Copy without attachnent/ enclosure "E" = Copy with attachn >:.denclosure "N" = No copy
,Il OFFICE PGEB
/7, T C:S @ pr SC:PGEB
- C:PGEB NAME EWang F JWdiEbl FAkstulewiczWkCarpente(P l
. DATE 04/01 /99 04/of/99 04/05/99 P* 04/ 5 /99 OFFICIAL RECORD COPY
(
h
t SEM/PWR-98: ECCS EVALUATION MODEL FOR PWR LBLOCA APPLICATIONS, EMF-2087(P), REVISION 0 (TAC NO. MA3457)
REQUESTS FOR ADDITIONAL INFORMATION 1.a Please provide a description of the methodology for calculating maximum peak cladding temperatures (PCTs) basec' ori stored energy versus exposure. Also, provide a plot of stored energy versus timelburnup up to the point of maximum PCTs using the new version of the creep modelin RODEX2 and a plot of the same calculational results using the same input with the earlier version of the creep modelire RODEX2. For both of these calculations, provide the time /burnup level at which maximum PCT was calculated by each code version. If maximum PCT is calculated to vary with burnup for different cores, please provide example calculations that cover the barnup range calculated for each code version.
1.b Please provide the predicteo primary creep (also secondary creep if calculated to be significant, but provide both values separately) versus time /burnup (at the axial location) up to which maximum PCT is calculated using the new creep model in RODEX2 (i.e.,
from the calculational results from Question 1.a). This may include more than one example if PCTs versus burnup differ for different cores. Also, provide the primary (and secondary if significant) creep prediction for at least 20 days beyond the time of calculated maximum PCT. Provide the range of input parameters (temperature and stres:,) used by the code at full power for calculating these creep predictions. Also, provide predicted creep versus time using the earlier creep model (MTYPE=0) for tM different time periods from the calculational results from Quettion 1.a (i.e., the time periods from the two creep models and different cores) and provide the range of input parameters (temperature and stress) for these examples.
2.
Please provide a better description of how the coefficients to the creep model are derived from the RODEX2 parameters provided in Table 3.9 and also define the columns of Table 3.10. What is the reason for the decrease in the average deviation of the gas release prediction with the new creep model provided in Table 3127 Is the reason because the new creep model predicts greater total (primary plus secondary) cladding creep than the earlier (MTYPE= 0) creep model?
3.
The submittal implies that the new version of RODEX2 (with the new primary creep model) will be applied only to PWR large break LOCAs. Also. based on past experience for PWRs, it is anticipated that peak stored energy will be calculated early in the first cycle cf operation for PWR large break LOCA initialization. Therefore, comparisons of the new version of RODEX2 code temperature predictions are only relevant to measured temperature data at low burnup levels and at relatively high temperatures that are representative of the initial stored energy for large break LOCA calculations. Please provide code predictions to centerline temperature data, similar to those provided in Figures 3-2 and 3-3 and the statistics from predictions in Tables 3.10 and 3.11, that have measured temperatures greater than 2750 degrees F and within the time period provided in response to Question 1 at wnich maximum PCT is calculated (i.e., exclude high burnup measured temperature data).
I
h g
l 4,
' The new creep model only appears to be compared to-- a) in-reactor creep data (from post-irradiation examination) from a couple of moderately high burnup rods (Figure 3.6) that are not applicable to primary creep (for PWR LOCAs), and b) out-of-reacter plastic deformation data of the cladding from these same rods (Table 3.8) taken at high stress values that are significantly greater than experienced in a PWR rod at low burnup levels.
l The moderately high burnup red creep data is totally dominated by secondary creep and I
is not a good measure of the accuracy (orconservatism) of the primary creep model which is the dominate model for large break LOCA stored energy. Also, the
= out-of-reactor data has stress values a factor of four higher than anticipated for a low burnup PWR rod. Therefore, the d.:t3 cornpared to the creep modelin the submittal are 1
not applicable to the low burnup application..ided for the new primary creep model.
Please provde comparisons of the new oreep model predictions to creep data from rods l
with low burnup that w I have a o%ter contribution due to primary creep rad a better measure of the conservatism in the primary creep model. Also, provide (!i available) l
- out-of-reactor primary creep data from irradiated cladding with lower stresses.
l Enclosure l.
l l
l i
f
]