ML20002C423
| ML20002C423 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 03/27/1972 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Morris P, Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8101100284 | |
| Download: ML20002C423 (6) | |
Text
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MAR 2 81972 *[0 March 27, 1972
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DOCKET CLERK f
s-Dr. Peter A. Morris, Director Re: Docket No 50-155 Division of Reactor Licensing License No DPR-6 United States Atomic Energy Commission Washington, DC 20545
Dear Dr. Morris:
Att:
Mr. D. J. Skovholt We are currently in the second week of a five-week refueling outage for the Big Rock Point Plant. The fuel sipping results have indicated the need to reuse % o Reload EG fuel bundles (EG-55 and -70) that were classified to be failed during the 1970 refueling outage.
Following the 1970 refueling outage, the failed rods in each fuel bundle (two per bundle) were removed and nuclear and thermal hydraulic analyses were performed to determine their suitability for reinsertion in the reactor.
Both EG-55 and EG-70 were in the reactor one cycle. Their exposures in mwd /t at the end ~of that cycle were 4441 and 3850, respec-tively. Visual examination of the failed fbel rods indicated that the failures were most likely due to hydriding of the cladding.
The repairs to EG-55 included the removal of the two failed fuel rods, A-4 and H-5, and the replacement of the two EEI mixed oxide rods with two fresh 2 5 w/o U-235 rods. One of the two vacancies in the fuel bundle is in a tie rod location. Engineering analysis per-formed on this bundle indicates the mechanical integrity is not affected by this vacancy. The lifting strength supplied by the seven existing tie rods is more than adequat,e for any normal anticipated lift require-ment on the bundles.
The two rods removed from EG-70 were B-7 and H-5 The reactivity of the repaired fuel bundles was calculated, assuming a bundle average exposure of 4,500 mwd /t, and is compared with a nonrepaired Reload EG bundle at the same exposure.
Bundle K.,
Reload EG 1.1352 E-55 1.1488 E-70 1.lh66 1Gd2 81 oi 1soA 8 Ly Y
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Dr. Peter A. Morris 2
Docket No 50-155 March 27,1(172 Nuclear calculations were performed on :hese two bundles and compared to peaking calculations on a Reload EG 1.undle at 5,000 mwd /t. The ratio of the rod power in a repaired bundle to the rod power in a nonrepaired bundle, assuming the same peynr is being produced in each bundle, is presented in Figures 1 and 2 (attached). Under the assumed conditions, the maximum increase in individual rod power is 19 4%. Because of the increase in rod power of some rods, assuning equivalent bundle powers, we are planning to insert these two bundles in core locations where their bundle power will not exceed the core average bundle power. The steady state and overpower condition heat flux limits specified by Section 5 2.1 of the Technical Specifications will, of course, be observed.
Because the two fuel bundles h tve a sligntly different con-figuration with two rods removed as comp tred with a normal fuel bundle, they were analyzed for possible adverse.termal hydraulic effects. This was done with a three-dimensional subchainel analysis in order to in-vestimte the effect on flow and CHFR (critical heat flux ratio) of re-moving the two rods. The results from tre three-dimensional analyses using the multired best-fit CHF correlation were compared with the results from normal one-aimensional analysis usirg the Hench-Levy CHF correlation.
This comparison shows that the one-dimensLonal calculation is conservative and tiit the additional flow areas create 1 by removing the fuel rods present no flow problem. Therefore, it has been concluded that normal one-dimensional calculations for CHFR can be applied to these two fuel bundles.
Based on the analyses presented above, we have concluded that these two fuel bundles are suitable for re 1se in the Big Rock Point Plant reactor. We have further concluded that the operating limits contained in the Technical Specifications are conservative. In our opinion, the removal of two fuel rods from each of thesa two fuel bundles does not constitute a sufficient change in this fuel to require a change in the Technical Specifications.
During the 15T(1 refueling outage, nine (9) EG bundles were classified as failed. Following the 1971 refueling outage, detailed nuclear calculations were perfomed to establish possible rod trades that would not affect fuel bundle nuclear characteristics.
During January 1(172, three good fuel bundles were formed by trading rods based on the nuclear calculations. Two more good fuel bundles were formed by trading rods that fell slightly outside of the criteria es-tablished by the aforementioned calculations. Further nuclear calcula-tions were perfomed on these two fuel bundlas. These calculations showed that the mui== change in local peaking fac tors was 0.6%. The resultant peaking factor for rods that increased in po ter was still less than the maximum rod peaking factor in the fuel bundles. Based on these calculations, i
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Dr. Peter I. Morris 3
Docket No 50-155 March 27, 1JT2 we have concluded that these five reconstituted EG fuel bundles are equivalent to the original EG fuel bundles. We plan to reinsert these fuel bundles in the Big Rock Point reactor during the present refuel-ing outage.
Yours very truly, i
RBS/ map Ralph B. Sewell Nuclear Licensing Administrator CC: Boyce H. Grier, USAEC i
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3-2 7 7 k EG-55 Relative Power Generation per Rod A
B c
D E
F G
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1 co 1.026 1.012 1.002 0 995 1.002 1.017 1.027 co 2
1.065 1.035 1.009 o.990 0.892 o.993 1.012 1.016 1.036 3
1.194 1.084 1.022 0 994 0 986 1.001 1.025 1.045 1.048 4
1.132 1.030 1.000 0 999 1.002 1.079 1.134 1.082 5
1.151 0 966 1.012 o.998 1.002 1.033 1.145 1.125 6
1.058 1.022 0 999 0 991 09% 1.018 1.076 1.131 1.080 7
1.031 1.011 0 994 0 984 0 981 0 997 1.018 1.034 1.039 8
1.023 0 999 o.998 o.984 o.890 0 988 1.001 1.011 1.024 9
co 1.016 1.008 o.996 0 992 0 999 1.007 1.015 co Relative Rod Power = New Local Peaking Factor 77 old Local Peaking Factor
- 75 (Assumes Equal Bundle Powers)
Figure 1
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EG-70 Relative Power Generation per Rod A
B c
D E
F G
H I
1 co 0 989 o.987 o.987 0 987 o.992 o.996 o.998 co 2
0 989 o.984 0 984 0 983 o.943 o.991 1.000 1.019 1.008 3
o.992 0 987 0 988 0 989 0 992 1.005 1.025 1.034 1.029 4
0 998 o.993 o.995 0 995 1.002 1.027 1.085 1.135 1.073 5
1.016 0 972 1.013 1.005 1.011 1.o40 1.156 1.120 6
1.058 1.103 1.063 1.021 1.010 1.029 1.087 1.135 1.073 7
1.100 1.108 1.027 1.004 1.010 1.027 1.035 1.o30 8
1.053 1.111 1.053 1.013 o.953 o.996 1.002 1.006 1.011 9
co 1.025 1.018 1.007 o.997 o.997 1.000 1.001 co 1
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ea ng Factor xH Relative Rod Power ~ old Local Peaking Factor 75 (Assumes Equal Bundle Powers)
Figure 2
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.1 F ROnt DATE OF DOCUMENT:
DATE RECEIVED NO; consumera Power my 3-27-72 3-28-72
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3g DESCRIP f EON ( M u REFERRED TO DATE l
RECErvED sv DATE of two Belosd EG fusil bundies (EG-55 &
w/9 cys for ACTION R}-70) during refueling outage at Big Rock Fotot w/attacbed Figures 1 & 2...
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