ML18044A893
| ML18044A893 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 05/14/1980 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML18044A892 | List: |
| References | |
| NUDOCS 8005160420 | |
| Download: ML18044A893 (4) | |
Text
CONSUMERS POWER COMPANY Docket 50-255 Request f.or. Change to the Techriical Specifications License DPR-20 For the reasons hereinafter set forth, it is requested that the Technical Specifications contained in the Provisional Operating License DPR-20, Docket 50-255, issued to Consumers Power Company on October 16, 1972, for the Palisades Plant be changed as described in Section I below:
I.
Changes A.
Change Section 3.10.3(g) to read:
"g.
The calculated value of FA shall be limited to < 1.45 (1.0 +
- r.
0.5 (1 - P)), the calculated value of FT* shall be limited to r
< 1. 77 (L 0 + 0. 5 (1 - P)), and the cal~ual ted value of F t.H shall r
be limited to~ *1.66 (1.0 + 0.5 (1 - P)}, where P is the core thermal power in fraction of core rated thermal power (2530.MWt)."
T
(*For the duration of Cycle-4 for H-fuel only, Fr for rods adjacent to the wide water gap shall be limited to < 1.90 (1.0 + 0.5 (1 -
P)).)
B.
Change Secti6n 3.11.g to read:
II g.
FA, FT and F* t.H shall be determined whenever the core power r
r r
distribution is evaluated.
If either FA, FT or F t.H is found to r
r r
be in excess of the limit specified in Section 3.10.3(g), within six hours thermal power shall be reduced to less than that required.to assure compliance with Section 3.10.3(g)."
2 II.
Discussion The above proposed* Technical Specifications changes are requested such that the total radial peaking.factor (FrT) limit will be changed to allow full power operation for Cycl~~4 H-fuel.
The Palisades Plant Cycle-4 core loading was design~d by Exxon Nuclear Company (ENC) using their PDQ computer code.
This particular code uses 2 energy groups and mixed number density (MND) thermal cross sections.
Consumers Power Company (CP Co) was requested by the NRC, letter dat~d July 11, 1979, to submit information which would provide assurance that water hole peaking was appropriately considered in the flux distribution calculations..
ENC compared their PDQ-2 energy group and PDQ-4 energy group results with the MONTE CARLO (XMC) results for a Palisades Plant fuel assembly.
The results showed that the PDQ-4 energy group model was in closer agreement with the MONTE CARLO model than the previously used PDQ-2 energy group model.
ENC was requested by CP Co to use the PDQ-4 energy group model to avoid further problems concerning calculational uncertainty factors caused by a significant underprediction of peaking factors.
ENC reanalyzed the Palisades Plant Cycle-4 using the PDQ-4 energy group MND model.
This resulted in a 5-6% higher peaking than what was previously analyzed.
At full power operation, the present Technical Specifications for the total radial peaking factor would be exceeded.
j The limiting location in the core is.the corner pin, adjacent to the control rod wide water gaps, in an H-assembly.
An analysis was performed by ENC to justify a higher FT (total radial r
peaking factor) along the wide water gap for H-fuel, while maintaining 3
the same limit cin total p~aking factor (Tech Spec Section 3.. 10.3(a5).
A report covering this.analysis (XN-NF-80-18, "ECCS and Thermal Hydraulic Analysis for Palisades Reload H Design,... April 1980) is attached.
The report concludes that for the duration of Cycle-4 for H-fuel only, an T
F along the wide water gap of 1.90 at full power is acceptable from r
both a LOCA and a DNB thermal margin point of view.
These Technical Specifications changes are needed only for Palisades Plant Cycle-4 for the following reasons:
A.
The enrichment for the corner pins in future batches will be reduced which will result in lower total radial peaking factors.
B.
Future cores will be designed. with the 4 group MND model which should help obtain loading patterns with an F T less than the r
previous~ 1.77 (1.0 + 0.5 (1 - P)) limit.
These requested Technical Specifications changes will allow the Palisades Plant to operate at full power for the total fuel cycle, whereas operation UIJ.der the present Technical Specifications will result in plant operation derated by about 12% power for part of this cycle.
III.
Conclusion Based on the foregoing, both the Palisades Plant Review Committee and the Safety and Audit Review Board have concluded that these changes are acceptable.
CONSUMERS POWER COMPANY B~~,fUJLZT R B DeWitt, Vice President Nuclear Operations Sworn and subscribed to before me this 14th day of May 1980.
- ~zt'.~
- -,-*'i!la:KCarStens, Notary Public
- *-: *, *Jackson_ County, Michigan
_,
- M)'. commission expires June 10, 1981.
..t' _,
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