ML20030A481
| ML20030A481 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 10/24/1974 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML20030A480 | List: |
| References | |
| NUDOCS 8101090664 | |
| Download: ML20030A481 (17) | |
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CONSUMERS POWER COMPANY Big Rock Point Plant Special Report 1.
Cycle 12 Fuel Performance Report 4
2.
Cycle 13 Start-Up Report 3
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Prepared by: Consumers Power Company October 24, 197h
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I.
CYCLE 12 FUEL PERFORMANCE (MAY 1974 - JUNE 1974)
A. - Introduction-The Cycle 12 fuel inspection was conducted during the June-July 1974 refueling outage. The fuel inspection was not extensive
.due.to the shoet duration of operation since the previous re-fueling outage (29 days). Personnel from General Electric Company, Exxon Nuclear Company and Consumers Power Company participated in the fuel inspection activities.
~B.
_ Work Scope _
1.
Consumers Power Company Consumers Power Company personael dry sipped all the fuel
- bundles in the core with the exception of thirtcan (13) "F" bundles initially inserted into the reactor in April 1974.
2.
General Electric Company Seven (T) failed standard "F" reload bundles were a.
visually examined by General Electric. Five (5) of
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these were three-cycle failures and two (2) were four-cycle failures. Selected photographs were taken of peripheral rod.s in the areas where rod failures 1
were suspected.
b.
Bundle CF-15 was converted to a standard "F" reload
. bundle by removing two EEI mixed oxide rods (DY-0019 and -0020) and replacing them with Urania fuel rods (WN-0011 and -0073) from Bundle CF lk.
3 Exxon Nuclear Company Exxon Nuclear-visually inspected the six (6) bundles a.
they built for Big Rock Point that had been irradiated daring Cycle 12.
i b.
Fuel rod length measurements were performed. Data was obtained on eight (8) rods,
/. total of thirty-four (34) fuel rods was gamma scanned.
c.
Six (6) of these were mixed oxide rods.
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End of Cycle 12 - Fuel Inspectior Resnits 1.
Consumers Power Company Dry sipping tests by Consumers Power indicated that fifteen (15) "F" fuel bundles had failed. Seven (T) of these were three-cycle failures with an average exposure of approxi-mately 8900 Wd/T. The other eight (8) were four-cycle failures with an average exposure of appvoximately 13,600 Wd/T. No other failures were found. The thirteen (13)
"F" bundles inserted into the reactor in April 197h were not sipped during this outage. The average exposure on these bundles was h37 Wd/T vith a peak exposure of 507 Wd/T.
2.
General Electric Company General Electric's visual inspection observations were characterized by significant crud deposition on the fuel rods and localized areas of crud spall.~ng.
There were instances of accelerated corrosion being visible where crud spalling had occurred. Significant crud spalling was ob-served below the bottom spacer grid on each of the seven (T) bundles inspected.
3 Exxon Nuclear Company Exxon's visual examination did not reveal any evidence of bundle degradation. There was no evidence of crud spalling on any of the six (6) Exxon bundles, not was there evidence of any corrosion product formation.
h.
Mixed,0xide Fuel Wrformance Ten (10) EEI m'.xed oxide fuel rods contained in "E" and "F" carrier bundles were irradiated during Cycle 12.
These ten (10) rods were icLtially inserted into the reactor at the beginning of Cycle 7 and have accumulated an average exposure of 18,570 Wa/T through Cycle 12..The Cycle 12 core aise contained eight (8) plutonium recycle fuel bundles (DA-01,
-02, -03 and -Oh, D-TP and -73, G01 and G02). All eight (8) h bundles were determined to be sound and have been reinserted into the core for Cycle 13.
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5.
Crud Deposition Based on previous experience no measurable increase in crud deposition was expected for Cycle 12 because of its short duration. For this reason, no fuel rod profilometry measure-ments were made during this outage.
Visual observations indicate that the amount of crud deposited during operation is decreasing with every cycle. The latest crud deposits may be characterized as fluffy and nontenacious.
D.
Summary Fifteen (15) failed fuel bundles were found during the outage after Cycle 12 as compared to nine (9) failures after Cycle 11.
Visual examination of seven (7) of the-failed bundles revealed moderate to severe crud spalling near.the bottom of the bundles.
EEI mixed oxide fuel rods and the plutonium recycle fuel bundles performed well during Cycle 12 with no resulting failures, f'
II.
CYCLE 13 START-UP REPORT A.
Introduction The 13th cycle at Big Rock Point was designed for operation between 230 and 240 MWg (ra ed power) for a period of approximately d
nine months. Included in this core loading are the following fuel types:
Fuel Type No of Assemblies General Electric Reload EG 2
General Electric Reload F Sh Exxon Nuclear J-l 2
Exxon Nuclear J-2 2
Exxon Nuclear Reload G 20 Nuclear Fuel Service Demonstration - Assemblies 4
Each of the Reload G, NFS-DA, and J-2 assemblies are plutenium i
recycle, mixed oxide designs.
In addition, Assembly E-65-contains
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two experimental EEI mixed oxide rods which have been in irradia-(
-tion since Cycle 7 The eighteen (18) fresh assemblies inserted in this cycle were all Reload G assemblies.
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B.
Experiments-Modifications were made to seventeen (17) assemblies during the 12th refueling outage for experimental purposes. These experi-ments include:
Experiment Modified Assemblies 1.
Exxon Densification and D-72, G01, G02 Cladding Ductility Studies 2.
General Electric Corner-F05, F08, F15, Flo, Rod Experiment F17, F20, F22, F30, F31, F37, F38, Fhl, Fh8, Fh9 The following is a brief description of these modifications:
1.
Exxon Densification and Cladding Ductility Studies The Exxon densification study was described in the Start-Up Report for Cycle 12 included in Special Report No 18 dated August 2, 1974. During the 12th refueling outage, the four (b) experimenta: fuel rods carried in Assembly D-72 were removed and replaced by the fuel rods present in the assembly prior to the experiment, restoring the assembly to its orir inal condition. The five (5) experimental rods in G02 were removed and replaced by three (3) of the five (5) fueled rods originally located in the assembly and two (2) inert rods. The two (2) original rods not reinserted in the as-sembly as well as one (1) fuel rod removed from Assembly G01 are to be returned to Exxon for cladding ductility studies.
The rod removed from G01 was also replaced by an inert rod.
The effect of these modifications on core operation was described in detail in a letter to the Directorate of Licensing dated July 9, 197h.
2.
GE Corner Rod Experiment This experiment was expanded from the two (2) Cycle 12 assemblies (eight rods) to twelve (12) assemblies in Cycle 13 (forty-eight rods). A description of this experiment and its effects on core operation can be found in a letter to the i
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Directorate of Licensing dated March 26, 197h.
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1 C.
Reactor Start-Up Upon completion of core reconstitution, core shutdown margin verification was successfully performed by the complete with-drawal of the strongest blade plus an additional six notches from an adjacent blade. Computer calculations indicated a total shutdown margin in excess of 3% Ak/k with the highest worth blade (3.8% Ak/k) withdrawn from the core.
The Cycle 13 BOC cold critical control rod pattern differed from computer predictions by seven notches (approximately 0.5% Ak/k).
Diagrams of the predicted and actual critical rod patterns are shown in Figure 1.
The moderator temperature coefficient test was conducted as required by Technical Specifications Section 5.2.4.
Results of the test indicated a maximum addition of reactivity of 9.6d from ambient (%70 F) to 122 F, well within the Technical Specifications limit of one dollar. Figures 2 and 3 are plots
. of p vs temperature and the temperature coefficient ( Ap/AT) va temperature.
Initial power escalation was very slow occurring over a period of one month. The slow stset-up is related to the General Electric concept of fuel preconditioning. Fluxvire measurements were taken at power levels of 147.1, 163.0, 176.8 and 198.1 MW.
g Soon after the first fluxvire run it became apparent that computer calculations and actual fluxvire measurements were not in good agreement. While the measured axial flux shapes were peaked at the top of the core, computer calculations predicted much flatter shapes peaked slightly toward the bottom. During the investiga-tion of this anomoly, it was found the flat power shape predicted by the computer analysis was very sensitive to changes in the vertical albedos input to the program. Because earlier cycles have been considerably more peaked than Cycle 13, the axial power shapes were relatively insensitive to changes in the albedos.
Although the computer codes have historically been less accurate k
in predicting the top peaked case, the problem had not previously i
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occurred to the exte.nt observed this time. It is felt that the particular rod pattern chosen this time to help limit the rate of power increase seen by certain fuel rods may have further contributed to the problem.- To justify their use in the calcu-
' lational model, the i;ew vertical albedos were used in a reanalysis of the previous three cycles (Cycles 10,11 :ind 12). In general, agreement between measured and calculated flax shapes was as good or even slightly iaproved over previous calculations.
Figures _ h through 11 are comparisons of the actual and calculated flux shapes for a recent Cycle 13 fluxvire measurement. The
- computer code (GROK) made use o'f the new vertical albedos for this comparison. Generally good agreement is indicated.
Once the mismatch between actual and calculated flux shapes vas resolved, the physics start-up was uneventful. All predicted and measured values were in good agreement and well within Technical Specifications.
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FIGURE 1 ACTUAL VS PREDICTED BOC 13 COLD CRITICAL ROD POSITIONS (23:OUT)
A B
C D
E F
1 6
7 6
7 2
7 0
0 0
0 6
3 6
0 0
0 0
7 4
7 0
0 0
0 6
5 6
0 0
0 0
7 6
7 6
7 6
PREDICTED CRITICAL A
B C
D E
F 1
5 7
5 7
2 7
0 0
0 0
5 3
5 0
0 0
0 7
4 7
0 0
0 0
5 5
5 0
0 0
0 7
6 7
6 7
5 ACTUAL CRITICAL
FIGURE 2 BIG. ROCK POINT PLANT TEMPERATURE COEFFICIENT TEST-JULY 1974 BOC -13 10.0 l* = 0.293605 E-04 SEC
[eff = 0.00611287 8.0 f
N x
6.0 4.0 2.0 -
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i 70 80 90 100 11 0 120 130 140 150 160
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BIG ROCK POINT PLANT REACTIVITY COEFFICIENT VS TEMPERATURE BOC 13
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1 80 100 120 140 160 180 200 TEMPERATURE OF I
FIGURE 4 NORMALIZED AXIAL PROFILE BIG ROCK POINT FLUXWIRE O
FLUXWIRE DATA OF 8-27-74 GROK A
LOCATION NO 1
- 1. 8
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-80 100 120 140 160 180 FLUXWIRE UNITS (1/2 INCH)
l FIGURE 5 NORMALIZED AXIAL PROFILE BIG ROCK POINT FLUXWlRE O
FLUXWIRE DATA OF 8-27-74 LOCATION NO 2 l
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40 60
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P FIGURE 6 NORMALIZED AXIAL PROFILE BIG ROCK POINT FLUXWlRE O
FLUXWIRE DATA
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LOCATION NO 3 1.8 1.6 1.4 OO 66$aa 0
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, P00,R ORIGINAL 40 60 80 100 120 140 160 180 FLUXWlRE UNITS ( 1/2 INCH )
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FIGURE 7 NORMAllZED AXIAL PROFILE BIG ROCK. POINT FLUXWIRE O
FLUXWIRE DATA GROK A
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A FIGURE 8 NORMALIZED AXIAL PROFILE BIG ROCK POINT FLUXWIRE O FLUXWIRE DATA GROK A
OF 8-27-74 LOCATION NO 5
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0 0.2 P00R ORIGINAL 40 60
, 80 100 120 140 160 180 FLUXWIRE UNITS ( 1/2 INCH )
FIGURE 9 NORMAllZED AXIAL PROFILE BIG ROCK POINT FLUXWIRE O
FLUXWlRE DATA OF 8-27-74 LOCATION NO.6 1.8 1.6 1.4 s
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I 40 60 80 10 0 120 14 0 16 0 180 FLUXWlRE UNITS (1/2 INCH)
P00R ORIGINAL
L FIGURE 10 i
NORMALIZED AXIAL PROFILE BIG ROCK POINT FLUXWIRE O
FLUXWIRE DATA O F 8-27-74 GROK d
LOCATION NO.7 1.8 1.6 1.4 O
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0.2 P00R ORIGINAL 40 60 80 100 120 14 0 16 0 18 0 FLUXWIRE UNITS (1/2 INCH)
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FIGURE 11
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NORMALIZED AXIAL PROFILE BIG ROCK POINT FLUXWIRE O
FLUXWIRE DATA OF 8-27-74 GROK d
LOCATION NO 8 1.8 1.6 1.4 x
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P00R ORIGINAL 40 60 80 10 0 12 0 14 0 16 0 180 FLUXWIRE UNITS (1/2 INCH)