ML22277A789

From kanterella
Jump to navigation Jump to search

E-61285, Enclosure 4, 013f1 Appendix 2.5-6, Document No. FFDC00561 E2, Rev. 4, Safety-Criticality Study Fresh UO2 Fuel Transportation Casks, Determining the Uncertainties to Apply to the Criticality Studies Performed Using Cristal (FCC-3/FC
ML22277A789
Person / Time
Site: 07103097
Issue date: 08/03/2022
From: Boyle R, Shaw D
TN Americas LLC
To:
Division of Fuel Management
Garcia-Santos N
Shared Package
ML22277A716 List: ... further results
References
A33010, L-2022-DOT-0008
Download: ML22277A789 (15)
v • d • e


Text

IDENTIFICATION REVISION I

FFDC00561 E2 11 4.0 I

AREVA NP A AREVA Fuel BU TOTAL NUMBER OF PAGES: 15 Safety-Criticality Study Fresh UO2 fuel transportation casks Determining the uncertainties to apply to the criticality studies performed using CRISTAL ADDITIONAL INFORMATION:

Criticality - Uncertainties - Shipping cask PROJECT DISTRIBUTION TO PURPOSE OF DISTRIBUTION HANDLING Public For application I I For action CATEGORY STR - Study Report For information STATUS BPE ROLES This text shall NAMESno be visible - Adjust frames over to ensure signature DATES ORGANIZATIONSblock will completely cover this text SIGNATURES AUTHOR REVIEWER APPROVER I

I I I I I I This text shall no be visible - Adjust frames over to ensure signature block will completely cover this text Classification Export AL: 0E001 ECCN: N RELEASE DATA: Les marchandises portant la désignation "AL inégal N" sont soumises la réglementation européenne ou allemande en matire de contrle des exportations au sein ou hors de l'UE. Les marchandises portant la désignation "ECCN inégal N" sont soumises la réglementation américaine. Les marchandises portant les désignations "AL:N" ou "ECCN:N" peuvent, selon la destination ou l'utilisation finales du produit, également tre soumises autorisation.

Export classification AL: 0E001 ECCN: N Goods labeled with AL not equal to N are subject to European or German export authorization when being exported within or out of the EU. Goods labeled with ECCN not equal to N are subject to US reexport authorization. Even without a label, or with label AL: N or ECCN: N, authorization may be required due to the final whereabouts and purpose for which the goods are to be used.

Exportkennzeichnung AL: 0E001 ECCN: N CHANGE CONTROL RECORDS: France: Y Die mit "AL ungleich N" gekennzeichneten Güter unterliegen bei der Ausfuhr aus der EU bzw.

This document, when revised, must be USA: N innergemeinschaftlichen Verbringung der europischen bzw. deutschen Ausfuhrgenehmigungspflicht. Die mit "ECCN ungleich N" gekennzeichneten Güter unterliegen der US-Reexportgenehmigungspflicht. Auch ohne reviewed or approved by following regions: Germany: N Kennzeichen, bzw. bei Kennzeichen "AL: N" oder "ECCN: N", kann sich eine Genehmigungspflicht, unter anderem durch den Endverbleib und Verwendungszweck der Güter, ergeben.

Non-proprietary document CW01 Rev. 4.5 - 08/03/17

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 2/15 AREVA REVISIONS DATE INDEX OBSERVATIONS 19/03/2004 B Additional information (Translation of French version to English).

13/05/2013 C Update for reference to CRISTAL V1.1 (synchronisation with the French version of Revision C)

See first 4.0 Update of the template of the document page Numerical revision number Addition of the new statistical uncertainty calculated with I I (§4.2.2.2,

§4.2.3 and §5) (synchronisation with the French version of Revision 4.0)

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 3/15 AREVA CONTENTS

1. INTRODUCTION ...................................................................................................................................................... 7
2. REGULATIONS ........................................................................................................................................................ 7
3. THE CRISTAL V1 PACKAGE ....................................................................................................................................... 8 3.1 CIGALES ..................................................................................................................................................................... 8 3.2 APOLLO2 .................................................................................................................................................................... 8 3.3 MORET4..................................................................................................................................................................... 8
4. DETERMINING CALCULATION UNCERTAINTIES ........................................................................................................ 9 4.1 PRELIMINARIES ............................................................................................................................................................... 9 4.2 APPLICATION OF UNCERTAINTIES TO THE CALCULATION RESULTS .............................................................................................. 9 4.2.1 Systematic uncertainty.......................................................................................................................................... 9 4.2.2 Statistical uncertainty ......................................................................................................................................... 10 4.2.3 Combined overall uncertainty ............................................................................................................................. 10
5. CONCLUSION ........................................................................................................................................................ 12 Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 4/15 AREVA LIST OF TABLES Table 1 : APOLLO2-MORET4 results for UO2 rod arrays in transportation configurations.................... 13 LIST OF FIGURES Figure 1 : Flow diagram explaining the CRISTAL package ................................................................... 14 Figure 2 : Calculation/measurement comparisons of the various calculation codes used..................... 15 Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 5/15 AREVA REFERENCES

[1] TS-R IAEA Safety Standards Series -

Regulations for the Safe Transport of Radioactive Material - 1996 Edition (As Amended 2003)

[2] TS-G-1.1 (ST2) - IAEA Safety Standards Series Advisory Material for the IAEA Regulations for the Safe Transport of Radioactive Material

[3] Framatome-ANP France Criticality Calculation Route - Qualification and Safety Margin Determination - M. Doucet and al - ICNC'2003 - Tokai Mura - Japan - October 20-24 2003

[4] NEA/NSC DOC(95)03 - September 2002 Edition International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP)

[5] DSU/SEC/T/2007 Indice A Contribution la qualification de la voie standard APOLLO2-MORET4 du formulaire de criticité CRISTAL Synthse des résultats de calcul obtenu avec la version V1.1 du formulaire CRISTAL.

[6] DSMR/96-393 - Eléments nécessaires l'expertise des études de criticité des emballages chargés de matires fissiles.

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 6/15 AREVA

SUMMARY

The purpose of this document is to determine the uncertainties to apply to the criticality studies performed using CRISTAL for casks used to transport fresh UO2 fuel assemblies or rods. The method used is based on IAEA regulations, and is generally valid for all Safety Authorities that apply IAEA regulations for the transportation of fissile material.

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 7/15 AREVA

1. INTRODUCTION Since 2002, a safety analysis report must be submitted for casks transporting fuel material, and must meet all regulations [1]. While no changes have been made regarding statutory mechanical and heat tests, justification of the results of criticality studies is, however, now formally required, as explained in

[2]. This justification must be based on comparisons between calculations and measurements that are representative of the configurations under study, in order to establish a reactivity bias, which is then included in the unrefined results.

This document describes the method used and the uncertainties obtained on the basis of [2], illustrated in [3] and applied in the CRISTAL package.

2. REGULATIONS Appendix VII of [2] entitled "Criticality Safety Assessments" gives a detailed description of the procedure for determining this uncertainty. The method used is briefly described below. The Upper Safety Limit (USL) is defined as follows:

USL = 1.00 - km - ku /1/

Where km is the "administrative" safety margin and cannot be compressed. In typical practice this is 5% k, And where ku is the reactivity bias from the calculations/measurements comparison for experiments close to the configurations to be evaluated by the criticality code package. This uncertainty depends on the calculation sequence used. One of the aims of this document is to describe the approach used for the CRISTAL package.

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 8/15 AREVA

3. THE CRISTAL V1 PACKAGE The CRISTAL package is made up of three main codes: CIGALES, APOLLO2 and MORET4.

A flow diagram explaining CRISTAL is shown in Figure 1.

3.1 CIGALES CIGALES is a code for processing physical data (fissile material, geometric shape, density, concentration, etc.) and which prepares datasets for APOLLO2. Its main functionalities are:

calculation of atomic concentrations for fissile environments, based on theoretical or experimental dilution laws, calculation of atomic concentrations for non-fissile environments and/or use of a predefined materials database (steel, concrete, etc.),

automated preparation of the APOLLO2 datasets, to perform:

o calculations based on collision probabilities (Pij), which produce neutron parameters such as k, B²m, etc., and homogenous and self-shielded macroscopic cross-sections for 3D MORET4 code, o reactivity calculations using the Sn method with 1D geometry, used mainly for criticality standards calculations.

3.2 APOLLO2 APOLLO2 is a cell / fuel assembly deterministic code for spectral calculations. It can use a variety of flow calculation types, such as the collision probability method (Pij) and the Sn method. The Pij solver approximates currents at the interfaces, making an exact 2D geometry. The Sn solver uses a diamond system. APOLLO2 uses an explicit self-shielding processing method, based on equivalence theories. It is also capable of providing self-shielded multigroup cross-sections for resonating isotopes. The version of APOLLO2 built into the CRISTAL V1.1 package uses sets of microscopic cross-sections from the JEF2.2 evaluation. The energy mesh used comprises 172 groups, making it possible to process correctly the neutron spectrum from 0 to 10 MeV. The homogenized and self-shielded macroscopic cross-sections featuring 172 energy groups are then sent to the MORET4 3D Monte Carlo code.

3.3 MORET4 MORET4 is a 3D calculation code that uses the Monte Carlo method to calculate the reactivity (Keff) in configurations of varying degrees of complexity, and the reaction rates in the different volumes that make up the configuration. Thanks to the aforementioned APOLLO2 calculations, MORET4 is well suited to the safety/criticality studies needed to justify fuel installations and the transportation of fissile material.

MORET4 uses the three conventional estimators (track length, collision and absorption) to determine Keff. These three estimators are combined with each sampling result, and a more general combination is used at the end of the calculation.

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 9/15 AREVA

4. DETERMINING CALCULATION UNCERTAINTIES 4.1 PRELIMINARIES Calculation uncertainties reflect the quality of the code sequence used to calculate the reactivity of a configuration. The codes used by AREVA NP to obtain a transportation authorization for fissile material are part of the CRISTAL V1.1 package, described in the previous section, and were the subject of a qualification file [5]. The qualification file is primarily based on the results of the international work group ICSBEP [4] and is supplemented by experiments performed by Frances CEA-Valduc and CEA-Cadarache. The file covers virtually the whole fuel cycle, from enrichment to reprocessing.

4.2 APPLICATION OF UNCERTAINTIES TO THE CALCULATION RESULTS The overall uncertainty value is obtained using the following formula:

I M Keff bias 2 s2 exp 2 t2 Where:

IM = uncertainty to be added to the calculated value Keff bias = systematic uncertainty derived from calculation/measurement comparisons (ignored if positive value) s = statistical uncertainty derived from the calculation, exp = statistical uncertainty derived from laboratory measurements, t = statistical uncertainty derived from manufacturing tolerances.

4.2.1 SYSTEMATIC UNCERTAINTY Systematic uncertainty is that which is deduced from Keff calculation/measurement comparisons.

Regarding rod arrays in transportation configurations, the qualification file [5] includes calculation/measurement comparisons based on the results of the work group ICSBEP [4]. This is available for consultation for further information on laboratory conditions.

The experimental results used in this analysis concern LEU COMP THERM 010 - 017 - 027 - 040 configurations, which include 25 configurations representing fresh UO2 fuel transportation, including various 235U enrichment levels, neutron-absorbing screens, reflectors and rod arrays.

The APOLLO2 - MORET4 results (from [5]) using these configurations are given in Table 1.

When we look at the results in this table, we see that, with one exception, the CRISTAL package overestimates the reactivity of the configurations under study. The only result that gave an underestimation was also analyzed using the other calculation codes and methods:

KENO IV - 27 energy groups - ENDF/BVI library:

Keff = I I MCNP - continuous energy - ENBF/BV library:

Keff = I I This underestimation would therefore seem to apply in general, and higher uncertainties than the one mentioned in [5]( I I) must be taken into account when interpreting laboratory measurements.

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 10/15 AREVA 4.2.2 STATISTICAL UNCERTAINTY There are three types of statistical uncertainty:

s = statistical uncertainty derived from the calculation, exp = statistical uncertainty derived from laboratory measurements, t = statistical uncertainty of the quadratic combination of the manufacturing tolerances.

4.2.2.1 EXPERIMENTAL UNCERTAINTY (exp)

The four experiment groups chosen for qualification each include a limited number of independent experiments. Statistically, we cannot therefore perform a quadratic combination of the measurement uncertainties. Instead, we use the arithmetic average of the uncertainties of all the experiments. An examination of Figure 2 confirms that the CRISTAL results overestimate the laboratory measurements, including uncertainties.

The average experimental uncertainty is calculated on the basis of the values in Table 1, and is I I.

4.2.2.2 STATISTICAL UNCERTAINTY DERIVED FROM CALCULATIONS (S)

All MORET4 results used in our studies are given with a maximum standard deviation of:

S = I I, for the studies performed before july 2013, S = I I, for the studies performed after july 2013.

4.2.2.3 MANUFACTURING TOLERANCE UNCERTAINTY (T)

This uncertainty is covered by the recommendations in document [6], which in criticality studies are applied to the pellet-gap and cladding dimensions.

When a neutron-absorbing poison is used, manufacturing tolerances are included conservatively in the studies.

In the special case where borated resin (FS69 type) is used for the FCC, the average density of the product is I I. Each resin batch is analyzed to determine the variability of the product in terms of meeting the isotopic specification and actual density per unit volume. This variability is I I. Worth noting in these calculations is the penalizing density of I I 4.2.3 COMBINED OVERALL UNCERTAINTY In section 4.2.1, we saw how there was a systematic positive deviation. This is an average value that must be corrected by the experimental and theoretical values, to verify whether the systematic bias is always positive. The verification is made using the following equation:

Keff bias Keff bias 2 exp 2 cal 2

Where:

Keff bias* = Average C-M, as shown in Table 1 (Em) (I I) exp

= Average experimental standard deviation as shown in Table 1 (I I) cal

= Average theoretical standard deviation as shown in Table 1 (I I)

This leads to a systematic corrected bias (Keff bias) of I Ipcm. This positive value is therefore not taken into account in the combined overall uncertainty.

To support this systematic zero bias, Figure 2 shows how the results of CRISTAL V1.1 rate against the measurements and results of other calculation codes used throughout the world.

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 11/15 AREVA Overall uncertainty IM (as defined in section 4.2), can therefore be defined as follows:

I M 2

  • exp2 s2 t2 Where, in this case :

s represents the standard deviation of industrial MORET4 calculations :

.r I o s = I I pcm, for the studies performed before july 2013, o s = I I pcm, for the studies performed after july 2013, exp = I I pcm t I I pcm.

From this we can deduce an uncertainty of:

I I pcm,. for the studies performed before july 2013 with s = I I pcm, I I pcm,. for the studies performed after july 2013 with s = I I pcm, Here, IM represents kU from equation /1/, with a systematic zero bias, as shown above.

Overall combination from equation /1/ gives us:

USL = 1.00 - km - kU for the studies performed before july 2013 with s = I I pcm:

I o USL = I I o USL = I I for the studies performed after july 2013 with s = I I pcm I

o USL = I I o USL = I I Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 12/15 AREVA

5. CONCLUSION This document demonstrates the safety/criticality approach used by AREVA NP in its application for authorization to transport fresh UO2 fuel with a maximum 235U enrichment of 5%, as a means of complying with IAEA regulations [1] and [2].

The reactivity uncertainty to apply to the CRISTAL results is:

I I pcm, for the studies performed before july 2013 with s = I I pcm, I I pcm, for the studies performed after july 2013 with s = I I pcm, which validates the CRISTAL package for criticality studies with the purpose to transporting fresh UO2 fuel with a maximum 235U enrichment of 5%.

Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 13/15 AREVA Table 1 : APOLLO2-MORET4 results for UO2 rod arrays in transportation configurations Proprietary table Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report AREVA Handling: Restricted AREVA Page 14/15 Figure 1 : Flow diagram explaining the CRISTAL package FORMULAIRE CRISTAL en w

  • W z

CIGALES JEF 2.2 z 0

Donnees 0 LOIS DE DILUTION nucleaires en w

EGM PREAPOL 0

1-Windows NT z w

PROCEDURES APROC THEMIS/NJOY THEMIS/NJOY ~

w I-1k'.

I-CESAR4 DARWIN CEA93 Sections Sections Ponctuellell llllultigroupe* Format

...J pendf

~

~

1-w TRIPOLI 4 0 Monte-Carlo z Energie continue 0

~

I-en K .11 (3D)

Taux de reactions VOIE DE REFERENCE Formulaire CRISTAL - CRISTAL package PC utilisateur - User PC Lois de dilution - Dilution laws Procédures APROC - APROC procedures Données nucléaires - Nuclear data Traitement des données - Data processing Station de travail - Workstation Méthode Pij - Pij method Sections multigroupes - Multigroup cross-sections Sections ponctuelles format pendf - Regular Pendf-format cross-sections

Énergie continue - Continuous energy Taux de reactions - Reaction rates Dimensions Keff données - Given Keff dimensions Flux-Curants - Flux-Current Voie standard - Standard route Voie de reference - Reference channel Non-proprietary document

A N° FFDC00561 E2 Rev. 4.0 STR - Study Report Handling: Restricted AREVA Page 15/15 AREVA Figure 2 : Calculation/measurement comparisons of the various calculation codes used C-M Comparison with Uncertainties Proprietary drawing Non-proprietary document

Retrieved from "https://kanterella.com/w/index.php?title=ML22277A789&oldid=3619082"