Design of MA-loaded Core Experiments using J-PARC
Takanori SUGAWARA*1, Kazuteru SUGINO2 and Toshinobu SASA1
1Nuclear Transmutation Technology Group, Japan Atomic Energy Agency,
Shirakata Shirane 2-4, Tokai-mura, Naka-gun, Ibaraki, Japan

2Reactor Physics Analysis and Evaluation Group, Japan Atomic Energy Agency,
Narita-machi 4002, Oarai, Ibaraki, Japan* E-mail: sugawara.takanori@jaea.go.jp

Uncertainties of the current minor actinide (MA) nuclear data are larger than those of other major
nuclides. Therefore, analyzed neutronic properties of MA-loaded fast reactor (FR) and accelerator driven
system (ADS) have much larger design margins in comparison with those of conventional FR. To improve
the reliability, safety and economical efficiency of these systems, it is required to increase the accuracy ofthe nuclear data of MA by the experimental data taken by adequate experimental conditions.
In this study, error analyses were performed to estimate “How much would the error caused by the MA
nuclear data decrease if the MA-loaded core experiments were performed”. TEF-P (Transmutation Physics
Experimental Facility), which is being planned to carry out basic experiments for MA-loaded systems inJAEA, was employed to simulate hypothetical MA-loaded core experiments. For the estimation, the crosssection adjustment procedure was employed.
These analysis results showed that the errors caused by the nuclear data were improved by considering
existing 233 integral data and 7 hypothetical results simulating TEF-P experiments. As a typical result, theerrors (the confidence level is 1σ) for the coolant void reactivity were improved from 2.4% to 1.4% for
MA-loaded FR and from 5.8% to 3.0% for ADS designed by JAEA.

1. Introduction
Research and development (R&D) for minor actinide (MA) transmutation technologies by using Fast
Reactor (FR) and Accelerator Driven System (ADS) have been performed at Japan Atomic Energy Agency(JAEA). Improvement on the neutronic design accuracy of the MA-loaded core is one of the mostimportant issues in the MA transmutation technology. Uncertainties of the current MA nuclear data arelarger than those of other major nuclides. Therefore, analyzed neutronic properties of MA-loaded FR andADS have much larger design margins in comparison with those of conventional FR. To improve thereliability, safety and economical efficiency of these systems, it is required to increase the accuracy of thenuclear data of MA by the experimental data taken by adequate experimental conditions.
JAEA plans a construction of “TEF-P” (Transmutation Physics Experimental Facility) in the second

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SND2006-V.10-1phase of the “J-PARC” (Japan Proton Accelerator Research Complex) project. TEF-P is a plate-type
fuelled critical assembly which is able to accept a proton beam (400MeV, 10W) delivered from a LINAC
of J-PARC. Various experiments are available in a critical condition or a sub-critical state driven byspallation neutrons. Furthermore, the experiments using pin-type MA fuel, which must be handled withremote devices, are planned to simulate the MA-loaded systems.
In this study, error analyses were performed to estimate “How much would the error caused by theMA nuclear data decrease if the MA-loaded core experiments at TEF-P were performed”. In this estimation,
the cross-section adjustment procedure was employed.

2. Procedure to estimate Errors caused by Nuclear Data
The error analyses were performed by the cross-section adjustment procedure [1]. This procedureadjusts the nuclear data to reduce the errors caused by the nuclear data and makes it possible to estimate theerrors quantitatively. Figure 1 shows a simplified schematic of this procedure (details are described in thereference [1]). Existing nuclear data (cross section T and covariance data M) such as JENDL-3.3 areadjusted by the Bayesian theorem by using sensitivity G, analytical modeling error Vm and experimental
error Ve for 233 integral data [1]. The adjusted nuclear data T’ and M’ are calculated as an output.
In this theory, the errors caused by the nuclear data are defined as GMGt (t means a transpose). So, it isavailable to compare the errors before the adjustment (GMGt) and after the adjustment by the 233 integral
data (GM’Gt). This procedure also enables to assess the effect of hypothetical experiments. In this study,
seven hypothetical MA experiment data at TEF-P were added to the 233 integral data to estimate “Howmuch would the error caused by the MA nuclear data decrease”. New adjusted nuclear data T’’ and M’’
were calculated and the error caused by the new data (GM’’Gt) was estimated.

3. Calculation Conditions(1) Hypothetical MA experiments
To simulate hypothetical MA experiments, the FCA XVII-1 core [2] which was a mock-up of a MOX
fueled fast reactor was referred. Figure 2 shows the RZ calculation model of the TEF-P core. The
characteristic and difference against the FCA core of the TEF-P are that it is available to treat the pin-type
MA fuel. The MA fuel pin was loaded in the TEST region. In this study, a MA-loaded FR and an ADS weretreated for the error analyses. For the FR analysis, U/Pu/MA(=77.4/17.6/5.0 wt%) oxide fuel pin
surrounded by Na was set to the TEST region. Pu/MA(31/69 wt%) nitride fuel surrounded by Pb-Bi was set
to the TEST region for the ADS analysis. The composition of MAs was Np-237/Am-241/Am-243/Cm-244= 11.1/44.4/22.2/22.2 wt% through this study.
In these calculations, the sensitivity was calculated by the SAGEP code [3] with 18 energy groupstructure. Seven calculation cases shown in Table 1 were performed; for a criticality, for a coolant void
reactivity and a Doppler reactivity. The analytical modeling error and the experimental errors weredetermined based on the FCA XVII-1 experiments described in the reference [1].

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(2) Object of estimation
In this study, the errors included in neutronic designs of the MA-loaded FR and the ADS wereestimated. The 1600MWt sodium cooled FR core studied in the feasibility study [4] was employed as atypical FR. Figure 3 shows the RZ calculation model of the FR core. 5 wt% MAs were added to the innerand outer core region. The 800MWt LBE (lead bismuth eutectic) cooled ADS designed by JAEA [5] wasemployed as a typical ADS core (Fig. 4). The sensitivities for the criticality, the coolant void reactivity(coolant volume fraction at the driver region was changed to 0%) and the Doppler reactivity (ΔT=500K atthe driver region) were calculated for both cores by SAGEP code.
(3) Nuclides and reactions for adjustment
In this study, nuclides and reactions whose covariance data were prepared in JENDL-3.3 were treatedfor the adjustment. Table 2 and Table 3 show the nuclides and reactions which were adjusted for the FR andthe ADS, respectively. As shown in these tables, covariance data for elastic and inelastic reactions of MAs
are not prepared in JENDL-3.3. Additionally, many covariance data which are important to analyze theerrors of the ADS are not prepared; such as capture and elastic reactions for Pb isotopes and Bi-209,
capture and inelastic reactions for N-15. In the present study, these nuclides and reactions which were notprepared in JENDL-3.3 were not considered; in other words, errors caused by these nuclides and reactions
were not included in present results.

4. Results and Discussion
The errors caused by the nuclear data are summarized in Table 4 for the FR and Table 5 for the ADS.
Figure 5-10 show the contributions of the nuclides and the reactions to the errors caused by the nuclear datafor each case. For the FR, the effect of the TEF-P experiments was shown as the improvement of the error
for Am-241 and Cm-244 capture reaction mainly though the changes (from 233 to 240) of the total error
were small for all cases.
For the ADS, the total error was decreased by the TEF-P experiments from 0.74% to 0.68% (from 233to 240) for the criticality, from 3.8% to 3.0 for the coolant void reactivity and from 4.0% to 2.8% for theDoppler reactivity. For the criticality, the changes of the errors for Am-241 capture reaction, N-15 elastic
reaction and inelastic reactions of the Pb isotopes and Bi-209 were prominent (Fig. 6). For the coolant void,the changes of the errors for Am-241 and Am-243 capture reactions, N-15 elastic reaction and inelastic
reactions of the Pb isotopes and Bi-209 were significant (Fig. 8). For the Doppler reactivity, the changes ofthe errors for Am-241 and Am-243 capture reactions, N-15 elastic reaction and capture reactions of Fe andZr-40 were impressive (Fig. 10).
However, the results for the ADS are not exact since the covariance data of many nuclides and reactions,such as elastic and inelastic reactions for MAs, capture and elastic reactions for the Pb isotopes and Bi-209
and capture and inelastic reactions for N-15 (Table 3), are not prepared as described above. To perform
more correct estimations, more experiments and estimations for MAs and other nuclides should be carriedout and an expansion of the covariance data is important.

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5. Conclusion
The error analyses were performed to estimate “How much would the error caused by the MA nuclear
data decrease if the MA-loaded core experiments at TEF-P were performed”. In this estimation, thecross-section adjustment procedure was employed for the FR and the ADS. The seven hypothetical TEF-Pexperiments were calculated and the sensitivities were used in the cross-section adjustment procedure.
These results showed that the TEF-P experiments with MA fuel were effective to improve the accuracyof the neutronic design for MA-loaded systems. For the ADS, the errors caused by the nuclear data werechanged from 0.74% to 0.68% for the criticality, from 3.8% to 3.0% for the coolant void reactivity andfrom 4.0% to 2.8% for the Doppler reactivity (from 233 to 240 int. data). On the other hand, these results
were unable to reduce the margins in the neutronic designs for the MA-loaded systems since the covariancedata for elastic and inelastic reactions for MAs were not considered. For the present ADS design, thecovariance data for capture and elastic reactions of Pb isotopes and Bi-209, capture and inelastic reactionsof N-15 and all reactions for Zr isotopes were also required since the quantities of these nuclides were verylarge in the present design. More experiments for MAs and other nuclides are important, and the expansionof the covariance data is also necessary.

References[1] T. Hazama, G. Chiba, K. Numata and W. Sato, Development of the Unified Cross-section Set ADJ2000R
for Fast Reactor Analysis, JNC TN9400 2002-064, Japan Nuclear Cycle Development Institute (JNC),(2002), (In Japanese).
[2] H. Oigawa, S. Iijima, T. Sakurai, et al., “A Proposal of Benchmark Calculation on Reactor Physics forMetallic Fueled and MOX Fueled LMFBR Based upon Mock-up Experiment at FCA”, J. Nucl. Sci. andTechnol., 37[2], 186, (2000).
[3] A. Hara, T. Takeda and Y. Kikuchi, SAGEP: Two-Dimensional Sensitivity Analysis Code Based on
Generalized Perturbation Theory, JAERI-M 84-027, Japan Atomic Energy Research Institute (JAERI),(1984), (In Japanese).
[4] JAEA, Feasibility Study on Commercialized Fast Reactor Cycle Systems - (1) Fast Reactor Plant
Systems –, JAEA-Research 2006-042, Japan Atomic Energy Agency (JAEA), (2006), (In Japanese).
[5] K. Tsujimoto, T. Sasa, K. Nishihara, et al., “Neutronics Design for Lead – Bismuth Cooled
Accelerator-Driven System for Transmutation of Minor Actinide”, J. Nucl. Sci. and Technol., 41[1], 21,(2004).

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Table 1: Calculation cases for hypothetical MA experiments at TEF-PCases

Analytical modelingExperimental error

error V’m[%]V’e[%]

Criticality

0.04

0.2

Void reactivity (1-3z)

1.0

5.0

Void reactivity (1-6z)

2.0

5.0

Void reactivity (1-9z)

3.0

10.0

Doppler reactivity (573K)

3.0

3.5

Doppler reactivity (823K)

3.0

4.0

Doppler reactivity (1073K)

3.0

4.5

Table 2:Nuclides and reactions for adjustment (FR) Table 3: Nuclides and reactions for adjustment (ADS)
Nuclide CaptureFissionνElasticInelasticχ μ-bar

Nuclide CaptureFissionνElasticInelasticχ μ-bar

U-235

○

○ ○ ○

○

○

○

Pu-238

○

○

U-238

○

○ ○ ○

○

○

○

Pu-239

○

○ ○ ○

○

○

○

Pu-238○○

Pu-240

○

○ ○ ○

○

○

○

Pu-239

○

○ ○ ○

○

○

○

Pu-241

○

○ ○ ○

○

Pu-240

○

○ ○ ○

○

○

○

Pu-242○○

Pu-241

○

○ ○ ○

○

○

Np-237○○ ○Pu-242○○

Am-241○○ ○Np-237○○ ○Am-242m○○

Am-241○○ ○Am-243○○ ○Am-243○○ ○Cm-244○○

Cm-244

○

○

N-15

O

○

--○

○

-○

FeFe

○

--

○

○

-○

Cr

○

--

○

○

-

Ni

○

--○

○

Na

○

--

○

○

2006 Symposium on Nuclear Data

○

--

○

○

--

○

○

-○

Cr

○

--

○

○

-○

○

Ni

○

--

○

○

-

○

-

○

Zr-40

○

--

○

--

○

Pb-206--○-

Pb-207--○-

Pb-208--○-Bi-209--○--

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Table 4: Errors caused by nuclear data (FR)BeforeAfter Adjustment by

After Adjustment by

Adjustment

233 int. data

240 (233+TEF-P) int. data

Criticality

1.06

0.30

0.27

Coolant Void Reactivity

2.43

1.57

1.36

Doppler Reactivity

3.76

2.16

1.71

unit [%]

Table 5: Errors caused by nuclear data (ADS)
BeforeAfter Adjustment by

After Adjustment by

Adjustment

233 int. data

240 (233+TEF-P) int. data

Criticality

1.08

0.74

0.68

Coolant Void Reactivity

5.80

3.82

2.98

Doppler Reactivity

4.92

3.99

2.77

unit [%]

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Present condition

Existing 233 Integral Data
Sensitivity：G
Analytical Modeling Error：VmExperimental Error：Ve

Existing Nuclear Data(JENDL-3.3)
Cross Section：T
Covariance：M

Cross-Section Adjustment
Procedure based on
Bayesian theorem

Adjusted Nuclear Data
Cross Section：T’
Covariance：M’This Study
Existing 233 Integral Data
+ 7 hypothetical MA experiments at TEF-P
Sensitivity：G’Analytical Modeling Error：V’m
Experimental Error：V’e

Adjusted Nuclear Data
Cross Section：T’’
Covariance：M’’Fig. 1: Procedure to estimate errors caused by nuclear data

Fig. 2: RZ model of TEF-P core

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Fig. 3: RZ model of FR core

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Fig. 4: RZ model of ADS core

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2006 Symposium on Nuclear Data

TOTALOthers

Bi209 INEL

Pb208 INEL

Pb207 INEL

Pb206 INEL

N15 ELAFe INEL

Cm244 CAP

Am243 NU

Am243 FIS

Am243 CAP

Am241 NU

Am241 FIS

Am241 CAP

Np237 NU

Np237 FIS

Np237 CAP

1Pu241 FIS

1.2

TOTAL

OthersNi CAPFe INEL

O ELA

O CAP

Pu239 CHICm244 CAP

Am243 CAP

Am241 NU

Am241 CAP

Pu240 NU

Pu240 FIS

Pu240 CAP

Pu239 INEL

Pu239 NU

Pu239 FIS

Pu239 CAP

U238 INEL

U238 ELAU238 NU

U238 FIS

U238 CAP

Error caused by nuclear data[%]
1Pu239 NU

Pu239 FIS

Pu239 CAP

Error caused by nuclear data[%]

1.2

Before adjustment
Adjustment (233)
Adjustment (240)

0.8

0.6

0.4

0.2

0-0.2

Fig. 5: Contribution of nuclides and reactions to errors caused by nuclear data (criticality, FR)
Before adjustment
Adjustment (233)
Adjustment (240)0.80.6

0.4

0.2

0-0.2

Fig. 6: Contribution of nuclides and reactions to errors caused by nuclear data (criticality, ADS)

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2006 Symposium on Nuclear DataTOTALOthersBi209 INEL

Pb208 INEL

Pb207 INEL

Pb206 INEL

Zr40 INEL

N15 ELAFe INELFe ELA

Cm244 FIS

Cm244 CAP

Am243 FIS

Am243 CAP

Am241 NU

Am241 FIS

Am241 CAP

Np237 FIS

Np237 CAP

Pu241 FIS

6Pu239 INEL

TOTALOthersNa INELNa ELANa CAPFe INELFe ELA

Fe CAP

O ELA

O CAP

Pu239 CHI

Cm244 CAP

Am243 CAP

Am241 CAP

Pu241 FIS

Pu239 INEL

Pu239 NU

Pu239 FIS

Pu239 CAP

U238 INEL

U238 ELAU238 CAP

Error caused by nuclear data[%]
2.5

Pu239 NU

Pu239 FIS

Pu239 CAP

Error caused by nuclear data[%]3

Before adjustment
Adjustment (233)
Adjustment (240)

21.5

10.5

0-0.5

Fig. 7: Contribution of nuclides and reactions to errors caused by nuclear data (coolant void reactivity, FR)
7

Before adjustment
Adjustment (233)
Adjustment (240)

5432

10-1

Fig. 8: Contribution of nuclides and reactions to errors caused by nuclear data (coolant void reactivity, ADS)

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2006 Symposium on Nuclear DataTOTALOthersBi209 INEL

Pb208 INEL

Pb207 INEL

Pb206 INEL

Zr40 CAP

N15 ELACr ELAFe INELFe CAP

Cm244 FIS

Cm244 CAP

Am243 FIS

Am243 CAP

Am241 NU

Am241 FIS

Am241 CAP

Np237 NU

5

Np237 FIS

6

Np237 CAPTOTALOthersNa ELANa CAP

Cr ELAFe INELFe ELA

Fe CAPO ELA

Pu239 CHI

Cm244 FIS

Cm244 CAP

Am243 CAP

Am241 CAP

Np237 CAP

Pu239 INEL

Pu239 NU

Pu239 FISPu239 CAP

U238 INEL

U238 ELAU238 NU

U238 CAP

Error caused by nuclear data[%]
3.5

Pu241 FIS

Pu239 FIS

Pu239 CAP

Error caused by nuclear data[%]4

Before adjustment
Adjustment (233)
Adjustment (240)

32.5

21.5

10.5

0-0.5

Fig. 9: Contribution of nuclides and reactions to errors caused by nuclear data (Doppler reactivity, FR)
Before adjustment
Adjustment (233)
Adjustment (240)

432

10-1

Fig. 10: Contribution of nuclides and reactions to errors caused by nuclear data (Doppler reactivity, ADS)

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