ML17194B624
| ML17194B624 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 07/07/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17194B623 | List: |
| References | |
| NUDOCS 8307080311 | |
| Download: ML17194B624 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. c. 2psss SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REALTOR REGULATION DRESDEN NUCLEAR POWER STATION, UNIT NO. 3
- DOCKET NO. 50-249 CONFIRMATORY CALCULATIONS REQUIRED BY THE DRESDEN UNIT 3 CYCLE 8 RELOAD SER The Dresden-3 Cycle-8 SER issued on April 29, 1982 stated that the licensee must confirm the adequacy of the present calculations or submit additional calculations of design strain, external corrosion, rod pressure, fuel centerline temperature, and transient strain for PCI with acceptable methods prior to reaching 10,000 MWd/MTU.
By letter dated April 25, 1983, the licensee submitted additional calculations of rod pressure and fuel melting temperature using the older GAPEXX code, which has NRC approval but is more conservative than desired.
The results showed that rod pressure and fuel centerline temperature will not exceed the system pressure and melting temperature, respectively, fcir assembly average burnups up to 15,000 MWd/MTU.
The licensee went further to demonstrate that variations of design strain, external corrosion, and PCI strain were insignificant in the burnup range of 10,000 to 15,000 MWd/MTU.
Thus, the lkensee requests an extension of the deadline from 10,000 MWd/MTU to 15,000 MWd/MTU or to the startup of next cycle, whichever occurs first, for the confirmatory calculations of design strain, external corrosion, and PCI strain with acceptable methods.
The licensee also performed PCT and cladding oxidation calculations by extending the MAPLHGR limit of 13 kW/ft from 10,000 to 15,000 MWd/MTU (assembly average).
The results showed that the PCT and cladding oxidation limits specified in 10 CFR 50.46 were met for burnups up to 15,000 MWd/MTU with the MAPLHGR limit of 13 kW/ft.
Inasmuch as (1) two important calculations, namely rod pressure and fuel melting temperature, were performed by using the approved GAPEXX code up to 15,000 MWd/MTU, (2) the variations of design strain, external corrosion and PCI strain are small from 10,000 to 15,000 MWd/MTU, (3) PCT and cladding oxidation continue to comply with requirements of 10 CFR 50.46 at the MAPLHGR limit of 13 kW/ft, and *(4) the licensee has. a commitment to perform those three calculations with fully acceptable methods prior to reaching 15,000 MWd/MTU or Cycle-9 startup, the staff concluded that the
~: '
licensee's request to extend the deadline for Cycle-8 confirmatory calculations is acceptable with no safety impact to the remaining operation of Cycle 8.
S. L. Wu prepared this evaluation.
Dated:
July 7, 1983