ML20028A153
| ML20028A153 | |
| Person / Time | |
|---|---|
| Issue date: | 10/20/1982 |
| From: | Thomas C Office of Nuclear Reactor Regulation |
| To: | Sherwood G GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 8211160506 | |
| Download: ML20028A153 (3) | |
Text
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OCT 2 0 B02 General Electric Company ATTN: Dr. G. G. Sherwood, Manager Safety and Licensing 175 Curtner Avenue San Jose, California 95114
Dear Dr. Sherwood:
Subject:
Request Number 2 for Additional Information on NEDE-23785-1(P)
We are currently reviewing the General Electric Company licensing topical report NEDE-23785-1(P) entitled "The GESTRA-LOCA and SAFER Models for the Evaluation of the Loss of Coolant Accident."
The continuing review of Volume 1 entitled "GESTRA-LOCA, a Model for the Protection of Fuel Rod Thernal Perfonnance" reveals the need for additional information as identified in the enclosure.
This additional information is necessary to continue the review - its expeditious submittal will, therefore, be to General Electric's advantage. Please advise us of your intended submittal date, so that we may schedule the continuing review.
Sincerely, j
Cecil 0. Thomas, Acting Chief Standardization and Special Projects Branch Division of Licensing
Enclosure:
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OCT 151982 OVESTI0flS Oft flEDE-23785-1-P (GESTR) 1.
For IFA-432 rods 1,'S and 6, please provide the end of life calculated
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fission gas release fraction. Also, for IFA-432 rods 1, 2, 3, 5, and.6, please provide the calculated temperatures at the thermocouple location versus linear heat generation rate for one early and one late life ramp i
in power.
2.
Please explain why GESTR-LOCA does no.t predict fuel temperatures for IFA-21 rods HCA and HCD and IFA-432 rod 4 as well as for other fuel rods.
3.
The gas release model has been calibrated and verified against a large volume of data that extends to high burnups.
How well characterized are those data above 40,000 tilld/liTM? Do they have well defined power histories, and if they do, what were the rod (time) averaged powers for these high burnup rods and at what burnup did the peak powers occur?
4.
The heat transfer resistances due to crud and oxide buildup on the cladding are mentioned in Section 3.1.1 of t1EDE-23785-1-P; however, the method of calculating these resistances is not presented.
Please give a description of how these cladding values are calculated.
5.
The irradiation data used to justify the irradiation swelling model extends only to a low burnup value. Have additional data been obtained at higher burnups and if so, please present them to justify the recommended swelling rate. Ilhat effect would doubling the fuel swelling rate for unrestrained fuel have on fuel temperature and end-of-life rod pressure?
6.
In Section 4.1 of f1EDE-23785-1-P it is implied that a thermocouple decalibration factor has been applied to all thernocouple data. A burnup-to-fluence conversion is given and it is implied that this conversion was used in the decalibration correction.
Has this burnup-to-fluence conversion factor been us'ed on all themocouple data?
If not, which data have it been app 1'ied to?
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7.
In Section 3.2.2.5 of NEDE-23785-1-P a term Gni, referred to as the
" nominal gap at start of time increment," is given.
Is this term a
" hot" or " cold" nominal gap?
8.
How does the GESTR-LOCA model correct pellet stiffness for pellet cracking? What effect would be seen on the thermal calculations and end-of-life rod pressures if the pellet stiffness due to pellet cracking in the current model was altered to assume greater pellet canpliance?
9.
What data have been used to develop the cladding axial irradiation growth model in GESTR?
10.
What is the uncertainty in the GESTR prediction of LOCA initial conditions, how is it derived, and how will it be applied in the overall LOCA analysis?
11.
Please provide GESTR predictions of fuel peak centerline tenperature, fuel peak volume-averaged temperature, peak pellet-to-cladding gap conductance, fuel rod internal pressure and rod-averaged fission gas release as a function of burnup for proposed 14.4 kW/ft LOCA conditions.
Please describe the input assumptions in sufficient detail to pennit a staff audit calculation.
12.
What is the sensitivity of the fission gas release fraction predicted by GESTR for the NRC PWR benchnark case cited in Reference 1 to final fuel density (94-98% T.D.) assumed in the calculation?
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REFERENCE 1.
J. F. Quirk (GE) letter to C. H. Berlinger (NRC), January 21, 1982.
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