ML18026A478

Rev 1 to Application of Anfb to ATRIUM-10 for Susquehanna Reloads.

ML18026A478
Person / Time
Site:	Susquehanna
Issue date:	03/28/1997
From:	Ingham J, Keheley T SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER
To:
References
EMF-97-010(NP), EMF-97-010(NP)-R01, EMF-97-10(NP), EMF-97-10(NP)-R1, NUDOCS 9704280180
Download: ML18026A478 (76)

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EMF-97-01 0(NP)

Revision 1 Application of ANFB to ATRIUM -10 for Susquehanna Reloads

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CkgA'arch 1997 9704280i80 970328 PDR ADQCK 05000387 P PDR Siemens Power Corporation Nuclear Division IIIIIII IIIIIIIIIIIIIIIIIIIIIIII IIIIIII

Siemens Power Corporation - Nuclear Division

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EMF-97-010(NP)

Revision 1 Issue Date: 3/28/97 Application of ANFB to ATRIUM'-10 for Susquehanna Reloads Prepared: ~

T. H. Keheley, taff gineer

~ ~ Date Safety Analysis Methods r.

Prepared:

. Ing I, Staff ngineer Date BWR Safety Analysis Major Contributor:

R. B. Macduff

Customer Disclaimer Important Notice Regarding Contents and Use of This Document Please Read Carefu/ly Siemens Power Corporation's warranties and representations concerning the subject matter of this document are those set forth in the agreement between Siemens Power Corporation and the Customer pursuant to which this document is issued.

Accordingly, except as otherwise expressly provided in such agreement, neither Siemens Power Corporation nor any person acting on its behalf:

makes any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this document, or that the use of any information, apparatus, method, or process disclosed in this document will not infringe privately owned rights; or

b. assumes any liabilities with respect to the use of, or for damages resulting from the use of, any information, apparatus, method, or process disclosed in this document.

The information contained herein is for the sole use of the Customer.

In order to avoid impairment of rights of Siemens Power Corporation in patents or inventions which may be included in the information contained in this document, the recipient, by its acceptance of this document, agrees not to publish or make public use (in the patent use of the term) of such information until so authorized in writing by Siemens Power Corporation or until after six (6) months following termination or expiration of the aforesaid Agreement and any extension thereof, unless expressly provided in the Agreement. No rights or licenses in or to any patents are implied by the furnishing of this document.

EMF-97-010(NP)

Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page i Nature of Changes Paragraph Item 1 ~ All,

~or Pa a s Dascri tion and Justification This is a major revision to the report to show new methodology.

E MF-97-01 0(NP1 Application of ANFB to ATRIUM -10 -

Revision 1 for Susquehanna Reloads Page ii I

E Contents

1. Introduction and Summary .... .1 1.1 Development of Conservative Additive Constants for the ATRIUM-10.......,. ..1 ~

1.2 Additive Constant Uncertainty for High Local Peaking Factors.......................2 1.3 'ethodology for Determining Flow Dependent MCPR Safety Limit.. ~.........~...2 ~

1.4 Methodology to Address AOOs . ................ ...... 2 ~

2. Application of ANFB Methodology to Part Length Rod Arrays...... ~ ..7 2.1 ANFB Base Correlation....... ,........................... ~.......... ..7 ~

2 2~ FEFF Definition .'............... ~ ~................... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 07 2.3 Additive Constant Determination ...~....... ~......... ~...........~......~.........8 ~ ~ ~

2. Sample Calculation. ~.............. .~................................. . ..

~ ~ ~ ~ .8 2A.1 FEFFbt Determination ................................. ........ .... 9 ~

2.4.2 Additive Constant Determination for a Full Length Rod..... .,..~..........9 ~

2.4.3 Additive Constant Determination With a Part Length Rod or Water Rod.................. ~...,..... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~ 1 0

3. ATRIUM-10 Cosine Dry Out Tests ...................... ~ .~ ..~............~........~.......14

4. ATRIUM-10 Downskew and Upskew Dry Out 4 1

~ Downskew Axial Power Tests ................ ..,.....~..................~....~......~...

Tests...........

~ ~

20 20 42~ Upskew Axial Power Test.~........... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ i ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~~~ ~ ~~ ~ ~~ ~ ~~o 20

5. Revision of the ATRIUM-10 Additive Constants... ....... . ... ..... 24

~ ~ ~ ~

5.1 Revised STS-17 FEFFbt's ........... .~........ ~..................... . ..~.......... ~...... ..24

~ ~ ~ ~ ~

5.2 STS-28.1 With Revised FEFFbt's .........~.............................~...~......25 5.3 STS-29.1 With Revised FEFFbt's ..~...........~.................... ~............~...........25 ~

6. Application of ANFB to ATRIUM-10 Fuel for Susquehanna....................... ~~ 58 6 1

~ Local Peaking Factor ....... .,................ . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ..58 6.2 Flow Dependence in ANFB for ATRIUM-10 Fuel ................~...... 59 6.3 Core Flow Dependent MCPR Safety Limit .... ~............ ~ ~ ~ ~ ~~ ~ ~ ~~ ~ ~~ ~ 60 6,4 Treatment of Flow Dependence for AOOs...........,...........~...,..60 6.5 MCPR Operating Limits. . ~........ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~ ~ ~ 61 6 .6 LOCA ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 61 6.7 Single Loop Pump Seizure Accident........~.............. .~........ ~

7 References ........ ~................................

~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~~~~~~~~~~ ~ ~ ~ ~ ~ ~~ ~~ ~ ~ 67

EMF-97-010(NP)

Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page iii Tables Table 1.1 Physical Characteristics of the ATRIUM'-10Test Assembly..........................4 Table 1.2 ATRIUM -10 Upper Lattice Additive Constants .. ~ . ......... 5 Table 1.3 ATRIUM 10 Lower Lattice Additive Constants... ~,..... ..,.

~ ~ ~ . .6 Table 2.1 FEFF Determination for STS-17.1 12 Table 2.2 FEFFbt Determination for STS-17.1 .... '.........~........~........~.....13 Table 3.1 Dry Out Test Matrix .... ~......

~ ~ ~ ~~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 1 5 Table 3.2 Original FEFFbt's Determined for the STS-17 Series of Tests ..........~............15 Table 3.3 STS-17 Critical Power Statistics With Original FEFFbt's.~...... ~....~......... ~,.. 16

~ ~ ~ ~

Table 5.1 Prediction of Low Flow Data for STS-17.4 With Original FEFFbt's ........,.......26 Table 5.2 Prediction of Low Flow Data for STS-17.4 With Revised FEFFbt's ............~...27 Table 5.3 STS-17 Critical Power Statistics With Revised FEFFbt's .....,... 28 Table 5A STS-17.1 Dry Out Test Summary ............,....................................... 29 Table 5.5 STS-17.2 Dry Out Test Summary .......,...........,...............................,.....,.30 Table 5.6 STS-17.3 Dry Out Test Summary .~........

~ ... ... .......... ..,..... .. 3 1

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Table 5.7 STS-17.4 Dry Out Test Summary ...........~..............~....... ~................... .32

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Table 5.8 STS-17.5 Dry Out Test Summary ...... ~.......................~........~...~....~..........34

~,......

~

Table 5.9 STS-17.6 Dry Out Test Summary ......... ......,...................... ~........35

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Table 5.10 STS-17.7 Dry Out Test Summary ... .,.........'.......

~ ~ 37 Table 5.11 STS-17.8 Dry Out Test Summary ....~............~...................,.. ~,............,.38 Table 5.12 STS-17.9 Dry Out Test Summary................~...........41 Table 5.13 STS-17.10 Dry Out Test Summary ............... ...............,.....42 Table 5.14 Table 5.15 Table 5.16 STS-17.12 Dry Out Test Summary STS-28.1 Dry Out Test Summary With Revised FEFFbt's .

.........44 STS-17.11 Dry Out Test Summary ............................~...,...,.~............ ~ ..43

.46 Table 5.17 STS-29.1 Dry'Out Test Summary With Revised FEFFbt's .................... .~.....48 ~

Table 6.1 Effect of Local Peaking on Additive Constants for Part Length Fuel Rods......,63 Table 6.2 Flow Trend for Upskew Axial Power Profile..., ~...,.......... ..~.... ~...........,.....63

~ ~ ~

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Application of ANFB to ATRIUM'-10 Revision 1.

for Susquehanna Reloads Page iv Figures Figure 3.1 Comparison of Flow and CPR for STS-17 With Original FEFFbt's ....~.............17 Figure 3.2 Comparison of Subcooling and CPR for STS-17 With Original FEFFbt's .~.......17 Figure 3.3 Comparison of Pressure and CPR for STS-17 With Original FEFFbt's .......... ..18 ~

Figure 3 4 Comparison of Measured Power and CPR for STS-17 With Original FEFFbt's .18 Figure 3.5 Predicted to Measured Critical Power for STS-17 With Original FEFFbt's .......19 Figure 4.1 Preliminary Comparison of Predicted to Measured Critical Power for the Downskew Axial Power Tests ......~......... .~......~... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~ ~ ~0 21 Figure 4.2 Preliminary Comparison of Predicted to Measured Critical Power for the Upskew Axial Power Tests ... ~....,....... ~ ......... ....... 22~

Figure 4.3 Data Comparison of Upskew, Cosine, and Downskew Axial Power Profile Dry Out Tests. 23 Figure 5.1 ANFB Comparisons for STS-17.4 With Original Additive Constants...............50 Figure 5.2 Comparison of Flow and Critical Power Ratio for STS-17 With Revised I+~ s F EFFbt ~ ~ ~ ~ ~ ~ ~~~ ~~~~ ~ ~ ~ ~ ~ ~ ~~~~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~ ~ ~ ~ 51 Figure 5.3 Comparison of Inlet Subcooling and Critical Power Ratio for STS-17 With R evised FEFFbt W+~

s ..... ~,......~....,.......

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 51 Figure 5A Comparison of System Pressure and Critical Power Ratio for STS-17 With R ewsed FFFFbt s ~ .... ~~~~~~~~~~~ ~... . .~ ~ ~~ ~~~~~~~~~~ . .

~ ~ ~ ~ ~ ~ ~ ~ ~ . ~~ ~~~ ~ ~ ~ ~~ ~~ ~ ~ ~~ ~ ~ ~ ~~~~ 52 Figure 5.5 Comparison of Measured Power and Critical Power Ratio for STS-17 With Revised FEFFbt's ...... ~......... ~ ~ ~ ~ ~ ~ ~ ~ ~ 52 Figure 5.6 Comparison of Predicted to Measured Critical Power for STS-17 With I +~

R evised FEFFbt s ~ ~ ~~~~~~~~~~ ~ ~ ~ ~ ~ ~ ~~~~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~~ ~ ~ ~ ~ ~~~~ ~~~ ~~ ~ ~ ~ ~ ~~ .53 Figure 5.7 Comparison of Flow and Critical Power Ratio for STS-28.1 With Revised F EFFbt s ~~~~ ~ ~ ~ ~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~ ~~ ~ ~ ~ ~ ~ ~~ ~ ~~~ ~ ~ ~ ~ ~~~ 54 Figure 5.8 Comparison of Inlet Subcooling and Critical Power Ratio for STS-28.1 With R evised FEFFbt s ...................................... ~ . ~ ~ ~ ~ ~..........~...... ....54 Figure 5.9 Comparison of Measured Power and Critical Power Ratio for STS-28.1 With R evised FEFFbt s ......................~.......... ..,............ ~ ~ ~ ~ . ..~....~.......

~ 55 Figure 5.10 Comparison of Flow and Critical Power Ratio for STS-29.1 With Revised F EFFbt s ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~ ~ ~ 55 Figure 5.11 Comparison of Inlet Subcooling and Critical Power Ratio for STS-29.1 With R evised FEFFbt s ........ .. . . ~... .~........,..., ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o'56 Figure 5.12 Comparison of Measured Power and Critical Power Ratio for STS-29.1 W'th Revised FEFFbt s..................~...... ~ ~ ~ ~....... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 56 Figure 5.13 Predicted to Measured Power for all ATRIUM -10 Dry Out Tests With Revised FEFFbt's...................... .. .~............~........ ~ ~ ~ ~ ~ .57 Figure 6.1 Susquehanna Unit 2 Cycle 9 ATRIUM'-10Lattice Local Peaking at 70/o Jold ....................". """ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~ ~~~ ~ ~ ~ ~ 64 Figure 6.2 ECPR vs. Flow and Axial Power Shape . ~...~...................................65 ~ ~ ~

Figure 6.3 Illustration of hCPR Adjustment to Account for ANFB Flow Dependence .......66

EMF-97-01 0(NP)

Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page v Distribution Controlled Distribution Richland K. V. Walters, 38 (15)

Document Control

EMF-97-010(NP)

Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 1 0 1. Introduction and Summary The purpose of this report is to describe methodology changes in the application of the ANFB critical power correlation to ATRIUM'-10 fuel at Susquehanna Steam Electric Station. This methodology will be used on an interim basis for the Susquehanna units with reloads of ATRIUM-10 fuel. [

The revised methodology involves changes in four areas:

~ Methodology for developing conservative Additive Constants for the ATRIUM-10 fuel,

~ Methodology to account for the potential increase in Additive Constant uncertainty for rods with a local peaking factor [ )

~ Methodology for determining a flow dependent MCPR Safety Limit to account for the observed flow dependence in ANFB predicted critical power.

~ Methodology for determining the change in Critical Power Ratio (bCPR) during Anticipated Operational Occurrences (AOOs) to account for the observed flow dependence in ANFB predicted critical power, 1.1 Development of Conservative Additive Constants for the ATRIUM-10 The ANFB Critical Power Correlation (Reference 1) has been successfully applied to full length rod arrays of Sx8, 9x9, and 10x10 assemblies. These assemblies included water rods and internal water channels. The Susquehanna reloads are the first reload application where ANFB is being applied to a fuel assembly with part length fuel rods.'he data base used to develop the ANFB correlation contains [ ] data points from tests

[

The U.S. NRC approved the correlation for use in March of 1990.

In the fall of 1992, Siemens conducted an extensive series of dry out tests on the ATRIUM-10 assembly [

EMF-97-010(NP)

Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 2 In the spring of 1994, a presentation by General Electric (Reference 2) at a technical conference suggested that their dry out correlation did not adequately predict dry out on upskew axial power profiles when part length rods were present. As a result, Siemens instituted a test program to confirm ANFB performance with upskew and downskew axial power profiles and plfr's. [

The results of the additional test program demonstrated that ANFB underpredicted critical power for downskew axial power profiles and overpredicted critical power for upskew axial power profiles for the ATRIUM-10. Therefore, the Additive Constants determined for ANFB from the 1992 testing were conservatively revised [

Sections 2, 3, 4, and 5 provide details on the ANFB-correlation and describe the generation of the ATRIUM-10 Additive Constants for use at Susquehanna Steam Electric Station.

An examination of the ATRIUM-10 data shows that, for rods experiencing boiling transition adjacent to part length fuel rods, there is a flow dependent trend in the critical power prediction. Although the overall mean of the ATRIUM-10 data is conservative, the flow trend indicates that additional conservatism should be added at low flows.

1.2 Additive Constant Uncertainty for High Local Peaking Factors During a recent inspection of SPC, the NRC expressed concern over a lack of sufficient dry out test data for bundle local peaking factors greater [ ]. SPC will address this concern by increasing the Additive Constant uncertainty used in the MCPR Safety Limit analysis for rods with a local peaking factor greater [ ] ~

1.3 Methodology for Determining Flow Dependent MCPR Safety Limit The revised MCPR Safety Limit methodology addresses an observed flow dependence in the accuracy of ANFB critical power predictions for ATRIUM-10 fuel. The relation of bundle flow to predicted critical power and flow dependent Additive Constant uncertainties is derived directly from ATRIUM-10 dry out test data. Safety limit calculations that account for the flow dependence in ANFB are performed at various core flows to generate a core flow dependent MCPR Safety Limit.

1.4 Methodology to Address AOOs The impact on AOOs of the ANFB flow dependence in critical power prediction, discussed above, is also addressed. For events that exhibit a decrease in bundle flow, the b,CPR is

EMF-97-010(NP)

Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 3

~

adjusted to account for the flow dependence using the assembly flow calculated during the AOO. ~

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l Table 1.1 Physical Characteristics of the ATRIUM'-10Test Assembly

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 5 Table 1.2 ATRIUM"-10 Upper Lattice Additive Constants

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 6 Table 1.3 ATRIUIVI'-10Lower Lattice Additive Constants

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 7

2. Application of ANFB Methodology to Part Length Rod Arrays The ANFB correlation uses assembly [

The correlation is described in detail in Reference 1.

2.1 ANFB Base Correlation The ANFB correlation has the form:

For a more detailed description of the ANFB base correlation, see Reference 1, Section 2.1.

2.2 FEFF Definition

[

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 8 2.3 Additive Constant Determination Additive Constants are derived from critical power tests performed for specific local peaking patterns, The procedure for determining the Additive Constant is as follows:

[

2.4 Sample Calculstion To demonstrate the determination of Additive Constants, a sample calculation follows. The sample used for the determination [ ] is test STS-17.1, Table 2.1.

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 9 2.'4.1 FEFFbt Determination It should be noted that the determination of the FEFFbt is not directly influenced by the presence or absence of part length fuel rods. [

This is presented in Table 2.1.

2.4.2 Additive Constant Determination for a Full Len th Rod

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 11 It should be noted that this example is for illustrative purposes only. As is seen from the previous definitions and examples, [

Experience has shown that a rod adjacent to a part length rod will experience a [

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 12 Table 2.1 FEFF Determination for STS-17.1

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 13 Table 2.2 FEFFbt Determination for STS-17.1

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 14 0 3. ATRIUM-10 Cosine Dry Out Tests In the Fall of 1992, Siemens undertook an extensive series of dry out tests to determine the critical power performance of the ATRIUM-10 bundle. The test series (STS-17) had [

]. The standard deviations were within those presented in Reference 1 for the ANFB data base.

Figure 3,1 compares the flow versus the critical power ratio (

] There were no obvious trends from the total data set.

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Application of ANFB to ATRIUM'-,10 Revision 1 for Susquehanna Reloads Page 15 Table 3.1 Dry Out Test Matrix Table 3.2 Original FEFFbt's Determined for the STS-17 Series of Tests

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 16 Table 3.3 STS-17 Critical Power Statistics With Original FEFFbt's 0

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Figure 3.1 Comparison of Flow and CPR for STS-17 With Original FEFFbt's Figure 3.2 Comparison of Subcooling and CPR for STS-17 With Original FEFFbt's

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 18 Figure 3.3 Comparison of Pressure and CPR for STS-17 With Original FEFFbt's Figure 3.4 Comparison of Measured Power and CPR for STS-17 With Original FEFFbt's

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 19 Figure 3.5 Predicted to Measured Critical Power for STS-'i7 With Original FEFFbt's

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4. ATRIUM-10 Downskew and Upskew Dry Out Tests In the Spring of 1994, a presentation by General Electric at a technical conference suggested that their dry out correlation did not adequately predict dry out for bundles with upskew axial power profiles if part length rods were present (Reference 2). Therefore, Siemens instituted a dry out program to confirm the performance of ANFB with downskew and upskew axial power profiles with part length rods present, The axial power shape of the heater rods was chosen [ ]

This peaking was chosen because it was as close as possible to the limit for heater rod design that still ensured no rod failures caused by heater wall thickness. [

Two downskew tests were performed, STS-28.1 and STS-28.2. The first test represented the radial power distribution of STS-17 4 (STS-28.1) and the second test represented the radial power distribution of STS-17.7 (STS-28.2). [

]. Figure 4.1 is a scatter plot of the predicted to measured critical power for the two tests.

4.2 Upskew Axial Power Test Preliminary analysis of the upskew axial power dry out test, STS-29.1, indicated that the original Additive Constants derived from the cosine tests overpredicted critical power, [

]. Figure 4.2 is a scatter plot of the predicted to measured critical power for this test using the original Additive Constants.

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 21 Figure 4.1 Preliminary Comparison of Predicted to Measured Critical Power for the Downskew Axial Power Tests

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Application of ANFB to ATRIUM"-10 Revision 1 for Susquehanna Reloads Page 22 Figure 4.2 Preliminary Comparison of Predicted to Measured Critical Power for the Upskew Axial Power Tests

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 23 Figure 4.3 Data Comparison of Upskew, Cosine, and Downskew Axial Power Profile Dry Out Tests

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5. Revision of the ATRIUM-10 Additive Constants The results of the upskew axial power tests show that the Additive Constants derived from the cosine tests need to be revised while maintaining the approved ANFB correlation. To account for the upskew test results, the Additive Constants were adjusted. [

5.1 Revised STS-17 FEFFbt's

]. Figure 5.1 is a plot of the STS-17.4 ANFB predicted critical power compared to the test data.

The solid line is the ANFB prediction. [

When the remainder of the STS-17 data is reviewed, [

J. These tests are STS-17.9, STS-17.10, and STS-17.11. [

For example, STS-17.7 shows no trends [ ]. STS-28.2 is a downskew test repeating STS-17.7; it shows no trends [

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 25 Selecting test STS-17.4 challenged [

5.2 STS-2S. 1 With Revised FEFFbt's The original FEFFbt's resulted in a conservative estimation of the downskew test data.

[

5.3 STS-29. 1 With Revised FEFFbt's The revised FEFFbt's are used to evaluate STS-29.1 and verify the ability of ANFB to predict the upskew data [

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 26 0 Table 5.1 Prediction of Low Flow Data for STS-17.4 With Original FEFFbt's

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 27 Table 5.2 Prediction of Low Flow Data for STS-17.4 With Revised FEFFbt's

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 28 Table 5.3 STS-17 Critical Power Statistics With Revised FEFFbt's

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 29 Table 5.4 STS-17.1 Dry Out Test Summary 0

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 30 Table 5.5 STS-17.2 Dry Out Test Summary

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 31 Table 6.6 STS-17.3 Dry Out Test Summary 0

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 32 Table 5.7 STS-17.4 Dry Out Test Summary

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 34 e Table 5.8 STS-17.5 Dry Out Test Summary

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 36 Table 6.9 STS-17.6 Dry Out Test Summary

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 37 Table 5.10 STS-17.7 Dry Out Test Summary 0

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 38 Table 5.11 STS-17.8 Dry Out Test Summary

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 41 Table 5.12 STS-17.9 Dry Out Test Summary

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 42 Table 5.13 STS-17.10 Dry Out Test Summary

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 43 Table 5.14 STS-17.11 Dry Out Test Summary

)

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 44 Table 5.15 STS-17.12 Dry Out Test Summary P

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 46 Table 5.16 STS-28.1 Dry Out Test Summary With Revised FEFFbt's

~ ~

~ ~

' ~ . ~ ~ ' ~

~ ~ ~ e

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 48 Table 5.17 STS-29.1 Dry Out Test Summary With Revised FEFFbt's

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 49

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 50 Figure 5.1 ANFB Comparisons for STS-17.4 With Original Additive Constants

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Application of ANFB to ATRIUM'-10 Revision for Susquehanna Reloads 1'age 51 Figure 5.2 Comparison of Flow and Critical Power Ratio for STS-17 With Revised FEFFbt's Figure 5.3 Comparison of Inlet Subcooling and Critical Power Ratio for STS-17 With Revised FEFFbt's

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 52 Figure 5.4 Comparison of System Pressure and Critical Power Ratio for STS-17 With Revised FEFFbt's Figure 5.5 Comparison of Measured Power and Critical Power Ratio for STS-17 With Revised FEFFbt's

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Figure 5.6 Comparison of Predicted to Measured Critical Power for STS-17 With Revised FEFFbt's

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 54 Figure 5.7 Comparison of Flow and Critical Power Ratio for STS-28.1 With Revised FEFFbt's Figure 5.8 Comparison of Inlet Subcooling and Critical Power Ratio for STS-28.1 With Revised FEFFbt's

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 55 0

Figure 5.9 Comparison of Measured Power and Critical Power Ratio for STS-28.1 With Revised FEFFbt's Figure 5.10 Comparison of Flow and Critical Power Ratio for STS-29.1 With Revised FEFFbt's

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 56 Figure 5.11 Comparison of Inlet Subcooling and Critical Power Ratio for STS-29.1 With Revised FEFFbt's Figure 5.12 Comparison of Measured Power and Critical Power Ratio for STS-29.1 With Revised FEFFbt's

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 57 0

Figure 5.13 Predicted to Measured Power for all ATRIUM'-10 Dry Out Tests With Revised FEFFbt's

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 58 0 6. Application of ANFB to ATRIUM-10 Fuel for Susquehanna This section addresses the application of ANFB to ATRIUM-10 licensing calculation for the Susquehanna Steam Electric Station. During discussions with SPC, the NRC staff identified several issues that SPC needed to resolve prior to operation of ATRIUM-10 fuel at Susquehanna. The two primary concerns are (1) the application of ANFB to ATRIUM-10 fuel when bundle local peaking factors exceed a local peaking factor [ ] (2) the flow dependence observed in the ANFB prediction of, critical power for some local peaking patterns. The proposed methodology to resolve these issues involves changes in four major areas:

~ Methodology for developing conservative Additive Constants for the ATRIUM-10 fuel ~

~ Methodology to account for the potential increase in additive constant uncertainty for rods with a local peaking factor greater [ j.

~ Methodology for determining a flow dependent MCPR Safety Limit to account for the observed flow dependence in ANFB predicted critical power.

~ Methodology for determining the change in BCPR during AOOs to account for the observed flow dependence in ANFB predicted critical power.

The development of the ATRIUM-10 Additive Constants for Susquehanna is discussed in Sections 2 through 5. The revised Additive Constants for ATRIUM-10 fuel shown in Tables 1.2 and 1,3 will be used in all licensing calculations and core monitoring for both Susquehanna units. The other three proposed methodology changes are discussed in the following sections.

6.1 Local Peaking Factor The maximum local peaking factor for the ATRIUM-10 lattice designs that will be used in Susquehanna Unit 2 Cycle 9 are presented in Figure 6.1 as a function of exposure. The local peaking factors are presented [

The IVlCPR Safety Limit analysis accounts for the effect of channel bow on local peaking.

Local peaking factors that include the effect of channel bow ("bowed" local peaking factors) may be higher than the nominal local peaking factors; [

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 59 During the dry out testing of ATRIUM-10 fuel, a pair of tests was performed that addressed the difference in Additive Constants [

6.2 Flow Dependence in ANFB for A TRIUM-10 Fuel

• Critical power data can be represented by the ECPR. ECPR is the ratio of the critical power predicted by ANFB for the test conditions to the critical power measured in the test. Figure 6.2 shows the ECPR as a function of bundle flow for ATRIUM-10 with the same local peaking pattern and different axial power profiles. This figure shows that, for ATRIUM-10 fuel with this local peaking pattern, [

The mean ECPR and the Additive Constant uncertainty have been determined from the upskew dry out test (STS-29.1) and are shown in Table 6.2 [

When the data for STS-29.1 was 'binned'ased on flow [ ] and the ECPR for each flow rate was determined, the Additive Constant variation with flow was removed. Therefore, if the standard deviation of each bin is examined, [

For bundle flows below [ ],an evaluation based on available ATRIUM-10 critical power data was performed to determine the ECPR and additive constant uncertainty. [

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Application of ANFB to ATRIUM"-10 Revision 1 for Susquehanna Reloads Page 60 The flow dependent mean ECPR and Additive Constant uncertainty shown in Table 6.2 will be used to calculate the core flow dependent MCPR Safety Limits, as discussed in Section 6.3.

6.3 Core Flow Dependent MCPR Safety Limit

]. This approach includes a method to calculate a core flow dependent MCPR Safety Limit that conservatively accounts for the ANFB flow dependence described in Section 6.2.

The NRC approved MCPR Safety Limit methodology is described in Reference 4. The safety limit evaluation is performed for each plant on a cycle specific basis. The methodology includes input parameters for both the Additive Constants and the Additive Constant uncertainty for each fuel design. The model addresses all bundles in the core and distinguishes among the bundles as to fuel design so that the Additive Constants and their uncertainty, local peaking, and number of rods are correctly characterized for each bundle.

II The SPC MCPR Safety Limit methodology will be used to calculate a core flow dependent MCPR Safety Limit. Safety limit calculations will be performed as a function of core flow using the revised Additive Constants for ATRIUM-10 fuel shown in Tables 1.2 and 1.3.

The flow dependent ECPRs and the corresponding Additive Constant uncertainty (see Section 6.2) will be used in the MCPR Safety Limit calculations as a function of bundle flow to determine the number of rods in boiling transition in each bundle. [

The calculated MCPR Safety Limits will be submitted by PPSL to the NRC for formal review and approval as part of the proposed cycle specific license amendment.

6.4 Treatment of Flow Dependence for AOOs The primary purpose of an AOO analysis is to calculate the d,CPR during the event. The d,CPR for the limiting transients are added to the MCPR Safety Limit to establish MCPR

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 61 Operating Limits as a function of core power and flow., As discussed in previous sections, ANFB has a flow dependence in its ability to predict critical power for some local peaking patterns. The flow dependence, represented by the calculated ECPR versus flow, was 0

conservatively derived from the ATRIUM-10 upskew power tests and is shown Table 6.2.

Because transient events can exhibit changes in bundle flow, an adjustment to the calculated hCPR is made to account for the ANFB flow dependence in the predicted critical power.

The following approach is used to adjust the calculated ATRIUM-10 dCPR to account for the effect of a flow change during an AOO. [

The impact of the flow dependence of ANFB on calculated B,CPR is illustrated in Figure 6.3.

As shown in the figure, a decrease in hot bundle flow during the event results in an increase in the calculated b,CPR.

6.5 MCPR Opereting Limits The adjusted bCPRs (Section 6.4) that account for the transient effect of the ANFB flow dependence are combined with the flow dependent MCPR Safety Limits (Section 6.3) to produce the cycle specific MCPR Operating Limits. The. resulting MCPR Operating Limits assure that 99.9'lo of the fuel rods are not expected to experience boiling transition during AOOs or normal operation.

6.6 LOCA The ANFB correlation is not used to assess dry out during LOCA calculations. This is consistent with SER limitation 3.3.(4), Reference 1. LOCA calculations are performed using an initial hot bundle power which is higher than that allowed by the MCPR Operating Limit. Therefore, ANFB is used to establish a conservatively high initial power for the hot channel LOCA analysis.

Application of the flow dependence and the revised Additive Constants (Tables 1.2 and 1.3) results in a reduction in the predicted critical power performance for ATRIUM-10 fuel.

The initial power for the hot channel in the ATRIUM-10 LOCA analysis was established using the original Additive Constants. Therefore, the hot channel power used in SPC ATRIUM-10 LOCA calculations is conservatively higher than the bundle power that can be reached while being monitored with the revised Additive Constants. Therefore, the results of SPC ATRIUM-10 LOCA calculations are conservative and applicable for ATRIUIVI-10fuel monitored using ANFB with the revised Additive Constants.

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 62

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6.7

~ Single Loop Pump Seizure Accident The acceptance criteria for the single loop pump seizure accident are that the calculated doses do not exceed a small fraction (10 /0) of the 10 CFR 100 guidelines. The MCPR Safety Limit methodology is used to calculate the number of rods which fail during this event as a function of the minimum CPR. The revised MCPR Safety Limit methodology described in Section 6.3 (with flow dependent ECPR and applicable Additive Constant uncertainty) will be used to calculate the number of rods that fail as a function of the CPR. The methodology described in Section 6.4 will be used to determine the 'inimum d,CPR during the accident. The adjusted bCPR will be used to determine the minimum CPR that occurs during the accident. Using this approach, the effect of the flow dependence observed in the upskew dry out tests will be conservatively accounted for in calculating the dose consequences for the single loop pump seizure accident.

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 63 Table 6.1 Effect of Local Peaking on Additive Constants for Part Length Fuel Rods Table 6.2 Flow Trend for Upskew Axial Power Profile

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 64 Figure 6.1 Susquehanna Unit 2 Cycle 9 ATRIUM'-10Lattice Locai Peaking at 70% Void

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 65 Figure 6.2 ECPR vs. Flow and Axial Power Shape

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Application of ANFB to ATRIUM -10 Revision 1 for Susquehanna Reloads Page 66 Figure 6.3 illustration of bCPR Adjustment to Account for ANFB Flow Dependence

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Application of ANFB to ATRIUM'-10 Revision 1 for Susquehanna Reloads Page 67

7. References ANFB Critical Power Correlation, ANF-1125(P)(A), and Supplement 1 and Supplement 2, Siemens Power Corporation - Nuclear Division, April 19, 1990.

2. B. Matzner, et al., "Improving BWR Fuel Critical Power without Increasing Bundle Pressure Drop, The 4th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety," April 1994, Taipei, Taiwan.

3. XCOBRA Code User's Manual, EMF-CC-043(P), Revision 3, Siemens Power Corporation - Nuclear Division, January 1996.

4. Advanced Nuclear Fuels Corporation Critical Power Methodology for Boiling Water Reactors, ANF-524(P)(A), Revision 2, Siemens Power Corporation - Nuclear Division, April 19, 1989.

5. Generic Mechanical Design Criteria for BWR Fuel Designs, ANF-89-98(P)(A),

Siemens Power Corporation - Nuclear Division, May 1995.