ML20215H675
| ML20215H675 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 10/17/1986 |
| From: | ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| To: | |
| Shared Package | |
| ML19292G104 | List: |
| References | |
| CEN-345(B)-NP, NUDOCS 8610240084 | |
| Download: ML20215H675 (20) | |
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CEN-345(B)-NP j je T
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i RESPONSES TO NRC QUESTIONS ON FATES 3B i
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l October 17, 1986 4
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COMBUSTION ENGINEERING, INC.
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8610240084 861021 PDR ADOCK 05000317 F
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LEGAL NOTICE TH18 REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY COM8USTION ENGINEERING, INC. NEITHER COM8USTION ENGINEERING NOR ANY PERSON ACTING ON ITS BEHALF:
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MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPUED INCLUDING THE WARRANTIES OF FITNESS FOR A PARTICULAR l
PURPOSE OR MERCHANTA81UTY, WITH RESPECT TO THE ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATION CONTAINED IN THIS REPORT, OR THAT THE USE OF ANY INFORMATION, APPARATUS, METHOD, OR PROCESS DISCLOSED IN THIS REPORT MAY NOT INFRINGE PRIVATELY OWNED RIGHTS;OR
- 8. ASSUMES ANY UA81UTIES WITH RESPECT TO THE USE OF,OR FOR DAMAGES RESULTING FROM THE USE OF, ANY INFORMATION, APPARATUS, METHOD OR PROCESS DISCLOSED IN THIS REPORT.
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QUESTION 1 Will the FATES 3B code replace FATES 3A code for all licensing applications? If not, please explain which codes will be used for which licensing application.
Also, will the inputs described in CEN-193(B), Supplement 2-P (dated March 21, 1982) for FATES 3 licensing applications remain the same for FATES 3B licensing applications. The conservative input used in FATES 3B for calculating LOCA initialization provides a conservative bias to this thermal calculation in addition to the~ inherent bias in the code. Please provide an estimate of the conservative bias in centerline temperature that is introduced in FATES 3B by the conservative LOCA input. Also, please provide a representative licensing calculation each for LOCA initialization and end-of-life rod pressure as an l
example of these applications.
RESPONSE 1 It is intended that the FATES 3B code replace FATES 3A for all Baltimore Gas and Electric licensing applications. All licensing applications for FATES 3B remain the same as given for FATES 3 in CEN-193(B), Supplement 2-P (dated March 21,1982).
l The input data for the FATES 3B licensing applications remain the same as that for FATES 3 described in CEN-193(B), Supplement 2-P, except for normal cy-cle-to-cycle variations. The procedure for introducing conservatism into the stored' energy for the LOCA analysis is described in detail in CEN-193(B),
Supplement 2-P.
This LOCA initialization licensing methodology is not expect-l ed to change when using FATES 3B. The bias in centerline temperature that is j
introduced in FATES 3B by the conservative LOCA input is essentially the same as that calculated for FATES 3.
This calculation of introduced conservatism is documented in CEN-220(B)-P (dated October 5, 1982). The introduced conserva-tism on volumetric average fuel temperature is still on th'e order of[
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The licensing calculation performed using FATE 53B for Calvert Cliffs Unit 1 Cycle 9 LOCA initialization is also used for the maximum end-of-life operating pressure. A set of values for FATES 3B mechanical design and thennal-hydraulic data are provided in Table 1-1.
The power history data are presented in~
Figures 1-1 and 1-2.
The[
] for the Calvert Cliffs Unit 1 Cycle 9 analysis is plotted in Figure 1-1.
Figure 1-2isaplotofthe{
]asafunctionofrod position, for the Calvert Cliffs Unit 1 Cycle 9 analysis.
Predicted temperatures and rod pressure for the aforementioned Calvert Cliffs Unit 1 Cycle 9 analysis are provided in Figures 1-3 and 1-4.
Figure 1-3 is a plot of the fuel centerline and fuel average temperatures as a function of rod average burnup. Thesetemperaturesarecalculatedbasedonthe[
]
peak power level.
Figure 1-4 is'a plot of the rod internal pressure pre-diction as a function of rod average burnup.
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1-2
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Table 1-1 FATES 3B Input Parameter Data Parameter Value pellet diameter, in, active fuel length, in.
pellet length, in.
fuel grain size, microns nominal fuel density, % TD tolerance on initial density, % TD densification, % TD pellet surface roughness, in, fuel enrichment, wt%
clad outer diameter, in, clad inner diameter, in, clad length, in.
3 end plenum void volume, in 3
total fuel rod void volume, in air partial pressure, psi fill gas partial pressure, psi helium in fill gas, fraction nitrogen in fill gas, fraction clad surface roughness, in.
-I heat transfer area per foot of rod per unit flow area, ft convective heat transfer coefficient, Btu /hr-ft
- F 2
maximum gap conductance, 8tu/hr-ft
- F 2
minimum gap conductance, Btu /hr-f't
- F coolant pressure, psia 2
coolant mass velocity, 1bm/hr-ft coolant inlet enthalphy, Btu /lbm core average LHGR, kw/ft 2
core average fast flux (> 1.0 MEV),/n/cm -sec 1-3
I Figure 1-1 CALVERT CLIFFS 1, CYCLE 9 W
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ROD AVERAGE BURNUP,GWD/WTU b
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Figure 1-2 CALVERT CLIFFS 1, CYCLE 9 BOL POWER VS AX1AL HOGHT t
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Figure 1-3 CALVERT CLIFFS 1, CYCLE 9
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FUEL TEMPERATURE VERSUS BURNUP O
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ROD AVERAGE BURNUP GWD/MTU O
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Figure 1-4 CALVERT CLIFFS 1, CYCLE 9 PRESSURE VERSUS BURNUP 5
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t ROD AVERAGE BURNUP.GWD/MTU e
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QUESTION 2
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RESPONSE 2 FATES 3B was developed to give improved predictions of fission gas _ release, with particular emphasis on improving the fission gas release predictions at high burnup. As part of the FATES 3B development process, C-E compiled and reviewed PWR high burnup, high temperature fission gas release data available from the open literature as well as from C-E programs. The development of the FATES 3B fission gas release model was based on the data utilized in CEN-161(B)-P, the RISO data discussed in CEN-193(B)-P,'and the following high burnup, high temperature data sets:
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Super-Ramp (Studsvik) Program, 2.
DOE High Burnup Ramp Program, i
3.
Zorita Research Development Program, and 4.
Westinghouse Research Program in BR-3.
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The five unpressurized BWR RISO rods were previously analyzed with FATES 3 at the request of the NRC to provide additional verification of the FATES 3 gas release model. This is documented in Reference 2-1.
These rods were rean-alyzed with FATES 3B. The measured fission gas release values for Rods PA29-4 and M2-2C from Test 022 are well predicted by FATES 38. As was the case in Reference 2-1, the measured gas release values for Rods M20-1B, M2-28, and T9-3B from Test 013 are considerably greater than the FATES 3B predictions for these rods. The FATES 3B temperature predictions for the Test 013 rods are lower than for the Test 022 rods, which is consistent with the differences in the reported irradiation histories of the two sets of rods. However, the post-. irradiation metallographic examination of the fuel pellets do not indi-cate any significant difference in operating temperatures between rods-of the two different test series, which is consistent with the observed gas release.
The higher-than-expected-fission gas release in the Test 013 series, based on reported test conditions, is unexplainable, and these three data points remain as outlyers.
It is C-E's position that althougn attempts to predict these rods are of interest, they carry no weight in assessing the quality of the fission gas release model.
The DOE High Burnup Ramp and Petten Ramp data should also be evaluated but must be used cautiously due-to the well-known effect of the position of the test rig in the Petten Reactor on the test results. This effect is discussed in Reference 2-2.
A core-distance parameter has been shown to affect fission gas release and PCI performance among PWR rods ramped at the Petten reactor.
l At Petten, ramp tests are performed in test capsules that reside outside the core. Rod powers are increased by moving the test capsule closer to the core.
The required movement is relatively small (see Reference 2.2) and the rod is subjected to important power gradients across the rod. Various factors i
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influence the radial position relative to the core periphery that must be attained by a given rod to achieve a predesignated peak ramp power. A corre-lation has beer:s determined, for example, showing that rods requiring the least distance from the core released significantly more fission gas and had less PCI resistance tha'n sister rods reported to be at the same power level, but at "l
a greater distance from the core. The core-distance effect is likely to be most pronounced for higher burnup fuel, which as a group, require the least i
distance from the core to attain higher ramp powers. This is an important consideration for the DOE High Burnup Ramp data. PWR fuel similar to that ramp tested at Petten was also' ramp tested at the R2 reactor as.part of the'-
Over-RampandSuper-Rampprograms.[
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Figure 2-1 of this response is a plot of the predicted versus measured gas releaseforthe[
]datapoints. The RISO Test 013 rods, DOE High Burnup Ramp rods, and Petten Ramp rods are identified with a separate symbol. The subset of reliable data created by removing the suspect RISO Test 013, DOE High Burnup Ramp rods, and the Petten Ramp rods fromthesetofrods[
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} Figure 2-1 shows that predicted versus measured gas release for the reliable subset of rods are well predicted on a best-estimate basis, especial-ly considering the limited number of reliable data points available in the high release regime. Figure 2-2 provides the entire FATES 3B fission gas release data base with these suspect rods identified.
For the[
], predicted-minus-measured gas release percent does not appear to be either burnup or tempera-ture dependent. Figure 2-3 is a plot of the predicted-minus-measured gas
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release as a function of rod average burnup for the high measured gas release
.i 2-3
rods. Likewise, Figure 2-4 is a plot of predicted-minus-measured gas release as a function of peak linear heat rate. Peak linear heat rate can reasonably be considered to correlate with the peak fuel temperatures.
In each of these plots, the RISO Test 013, DOE High Burnup Ramp, and Petten Ramp rods are again identified with a separate symbol. Whether or not the RISO Test 013, DOE High Burnup Ramp, and Petten Ramp data points are included, the FATES 3B predict-ed-minus-measured gas release percent appears to be quite independent of burnup or power level.
Considering (1) how well the high fission gas release is credicted when the questionable data is removed (see Figure 2-1), and (2) that the predict-ed-minus-measured gas release (error) is independent of burnup and power level (ortemperature)[
],itcan be concluded that the FATES 3B gas release model is adequate for predicting fission gas release. Becauseofonlyaslightbias(
]theimpacton licensing calculations is negligible.
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REFERENCES for RESPONSE 2 2-1 Combustion Engin'eering, Inc., " Partial Response to NRC Questions on CEN-161(6), Improvements to Fuel Evaluation Model", CEN-193(B) Supplement
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2-P, March 21,1982 (Proprietary).
2-2 J. C. LaVake and M. Gaertner, "High Burnup PWR Ramp Test Program, Topical Report Background Ramp Test Results", DOE-ET/34030-4, CEN-402, December 1982.
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Figure 2-1 FISSION GAS RELEASE PREDICTED VS WEASURED FGR him h
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FISSION GAS RELEASE PREDICTED FGR VS MEASURED FGR F
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MEASURED GAS RELEASE,%
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Figure 2-4 FISSION GAS RELEASE
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PREDICTED-MEASURED VS PLNR
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PEAK UNEAR HEAT RATE,KW/FT 2-9
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QUESTION 3 Are the fission gas release and thermal expansion models the only, differences between FATES 3A and FATES 3B codes.
RESPONSE 3 The only differences between FATES?A and FATES 3B codes are the models related to fission gas release and the thermal expansion model as described in CEN-161(B)P, Supplement 1-P.
Although C-E' changed the grain growth'model as described, grain growth is considered to be part of the fission gas release model. However, it should be noted that FATES 3A is considered to be the FATES 3 code (CEN-161(B)-P) with the NRC imposed restriction on the grain size used in the fission gas release calculations. The grain size restriction is not part of FATES 3B. The descriptions in Supplem'ent 1-P for FATES 3B only include the FATES 3B differences from the original FATES 3 code described in CEN-161 (B)-P.
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QUESTION 5 Are the thermocouple data points used for FATES 3B comparisons in Table 3-13 and Figures 3-3 through 3-5 the same data as used for the FATES 3 comparisons in CEN-220(B) (dated October 5, 1982).
If data were added or deleted please explain why each data group was added or deleted. Also please provide a copy
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ofCEN-220(B).
RESPONSE 5
-The data groups (rods) used to examine the FATES 3B bias and uncertainty in predicting fuel temperatures are the same as those used for the FATES 3 compar-isonsinCEN-220(B). Specifically, measured versus predicted temperatures were p' resented for the following test rods: (
)However,theFATES3Bmodelingofthe[
] rods was improved,resultingin[
] data points for these[ ] test rods.
~Thenumberofdatapointsforthesame[]rodspresentedinCEN-220(B)was b
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