2. BASIC SPECIFICATION OF THE NEXT GENERATION NCS SYSTEM
3.2 REACTION RATE DISTRIBUTION
Figure 3 represents the plots of C/E value on Pu-239 fission reaction rate distribution in the radial direction for ZPPR-13A. The old JFS-3 NCS systematically underestimated reaction rate in the blanket region, and the application of the new NCS improved to a certain extent. However ERANOS evaluated with high accuracy and it was found that the use of the 1968-group NCS raised the reaction rate in the blanket region by increasing the elastic removal cross sections and decreasing the transport cross sections.
1.10
1.05
0)
?1.00
s
0.95
0.90
Old JFS-3 (JENDL-3.2) New constant set (JENDL-3.2)
•A-- ERANOS (JEF-2.2)
20 40 60 80 100 120 Distance from the core center [cm]
140 160
Fig.3 Summary of results on reaction rate distribution analyses (ZPPR-13A Pu-239 fission reaction rate)
3.3 REACTIVITY
Figure 4 describes the summary of results on reactivity parameters analyses. The use of the NCS improved the exceeding underestimation of Doppler reactivity and systematic overestimation of sodium void reactivity by the old JFS-3, and did not affect the result on the control rod worth. The systematic difference in C/E value of the control rod worth between the JNC and ERANOS systems is due to that of the calculated effective delayed neutron fraction. There still remains the overestimation in the ZPPR-13A sodium void reactivity though ERANOS well-estimated.
1.4 1.3
J.2
a>
I S
1.0 0.9 0.8
-Old JFS-3 (JENDL-3.2)
•New constant set (JENDL-3.2)
•A- ERANOS (JEF-2.2)
Doppler reactivity (Step5)
Pair control rod worth
Sodium void reactivity (Step3)
R=22cm R=110cm
ZPPR-9 ZPPR-9 ZPPR-13A ZPPR-9 ZPPR-9 Assembly
Fig.4 Summary of results on JUPITER reactivity analyses
JAERI-Conf 2001-009
4. CONSIDERATION
The use of the new NCS affected the result of analyses on reaction rate in the blanket region, Doppler reactivity and sodium void reactivity, which are sensitive to the cross sections in several keV. Fig.5 represents the comparison of macroscopic cross section produced between by the old JFS-3 and by the new NCS. Difference in total and elastic cross sections is not systematic. But elastic removal cross sections of the old JFS-3 were systematically underestimated compared with those of the new NCS, and that was considerable in the vicinity of 3keV. It is considered that the underestimation in removal cross sections causes the harder neutron spectrum and reduces the contribution in several keV region.
0.04 0.03
£ 0.02 o, g 0.01
Po> 0.00 it
.2-0.01 1 -0.02
<
-0.03 -0.04
_
Total
Elastic scattering
—^Elastic removal
r-L£^J-j_j_«-|_P"
1E+2 1E+3 1E+4 1E+5 Energy [eV]
1E+6 1E+7
Fig.5 Absolute difference in macroscopic cross sections of homogeneous fuel cell between the old JFS-3 and the new constant sets (Reference: New constant set)
5. CONCLUSION
The next generation NCS system has been incorporated for the feasible preparation of NCS for fast reactor analyses. The tentative new NCS was prepared using the NCS system and applied to the JUPITER analyses. The use of the new NCS improved the results compared with that of the old JFS-3 NCS. In comparison with ERANOS there is a room for improvement of analyses in several parameters. Therefore it is considered that further investigations are required on processing and structure of NCS.
ACKNOWLEDGEMENTS
The author deeply appreciates Mr. Kaneko of Integrated Technical Information Research Organization, Ltd. for the integration of the nuclear constant processing system and many adequate advices.
REFERENCES
[1] Lineberry M. J., Carpenter S. G. et al.: "Experimental Studies of Large Conventional
LMFBR Cores at ZPPR," Proc. of Fast Reactor Physics 1979, Aix-en-Provence, France, IAEA-SM-244/86, Vol.1, P. 187 (1979).
[2] McFarlane H. F., Carpenter S. G. et al.: "Experimental Studies of Radially Heterogeneous Liquid-Metal Fast Breeder Reactor Critical Assemblies at the Zero-Power Plutonium Reactor," Nucl. Sci. Eng., Vol.87, P.204 (1984).
[3] Collins P. J. and Brumbach S. B.: Experiments and Analysis for an Axially Heterogeneous LMR Assembly at ZPPR," Proc. of the 1988 Int. Reactor Physics Conf., Sep.
18-22, Jackson Hole, Wyoming, 1988, Vol.2, P.309 (1988).
[4] Takano H. and Kaneko K.: "Revision of Fast Reactor Group Constant Set JFS-3-J2,"
JAERI-M 89-141 (1989) (in Japanese).
[5] Nakagawa T., Shibata K. et al.: "Japanese Evaluated Nuclear Data Library Version 3 Revision-2: JENDL-3.2", J. Nucl. Sci. Technol., 32, 1259 (1995).
[6] Ishikawa M.: "Consistency Evaluation of JUPITER Experiment and Analysis for Large FBR Cores," Proc. of Int. Conf. on the Physics of Reactors (PHYSOR96), Mito, Japan, Vol.2, P.E-36 (1996).
[7] Nordborg C, Salvatores M.: "Status of the JEF Evaluated Data Library", Proc. of Int.
Conf. on Nuclear Data for Science and Technology, Gatlinburg, Tennessee, May 9-13, 1994, Vol.2, P.680 (1994).
[8] Grimstone M. J., Rimpault G. et al.: "The Geometrical Treatment in the New European Cell Code ECCO," Top. Mtg. on Advances in Nuclear Engineering Computation and Radiation Shielding, Santa Fe, New Mexico (1989).
[9] Doriath J. Y., McCallien C. W. et al.: "ERANOSl: The Advanced European System of Codes for Reactor Physics Calculation," Int. Conf. on Mathematical Methods and Super Computing in Nuclear Applications, Karlsruhe, Germany (1993).
[10] Sugino K. and Rimpault G.: "Analyses of the JUPITER Fast Reactor Experiments Using the ERANOS and JNC Code Systems," ANS Int. Top. Mtg. on Advances in Reactor Physics and Mathematics and Computation into the Next Millennium (PHYSOR 2000), May 7-12, 2000, Pittsburgh, Pennsylvania, X.E.-l (2000).
[11] Tone T. and Katsuragi S.: "PROF GROUCH-G A Processing Code for Group Constants for a Fast Reactor," JAERI 1192 (1970).
[12] Takano H., Ishiguro Y. et al.: "TIMS-1: A Processing Code for Production of Group Constants of Heavy Resonant Nuclei," JAERI 1267 (1980).
[13] Takeno H., Hasegawa A. et al.: "TIMS-PGG: A Code System for Producing Group Constants in Fast Neutron Energy Region," JAERI-M 82-072 (1982) (in Japanese).
[14] MacFarlane R. E. and Muir D. W.: "The NJOY Nuclear Data Processing System Version 91," LA-12740-M Manual UC-413 (1994).
[15] Mori T. and Nakagawa M.: "MVP/GMVP: General Purpose Monte Carlo Codes for Neutron and Photon Transport Calculations based on Continuous Energy and Multigroup Methods," JAERI-Data/Code 94-007 (1994) (in Japanese).
JP0150766
JAERI-Conf 2001-009
5. Covariance Data Processing Code: ERRORJ Kazuaki KOSAKO
Sumitomo Atomic Energy Industries, Ltd.
2-10-14 Ryogoku, Sumida-ku, Tokyo 130-0026 e-mail: [email protected]
The covariance data processing code, ERRORJ, was developed to process the covariance data of JENDL-3.2. ERRORJ has the processing functions of covariance data for cross sections including resonance parameters, angular distribution and energy distribution.
1. Introduction
The evaluation research of covariance data for JENDL-3.2 [1,2] was carried out in Covariance Evaluation Working Group. It will be applied to new covariance data stored in dominant nuclides of latest JENDL-3.3. The nuclides evaluated covariance data are 10, B-11, 0-16, Na-23, Cr, Mn-55, Fe3 Ni, U-233, -235, -238, Pu-239, -240, and -241. U and Pu include the general resolved resonance parameter format (Breit-Wigner or Reigh-Moore) and the unresolved resonance format. The research of reactor constant adjustment method for fast reactor is progressing in JNC. The method needs multigroup covariance data to adjust the reactor constant.
The processing codes for covariance data in the evaluated nuclear data file are NJOY [3] and PUFF-2 [4], in Japan. PUFF-2 corresponds to ENDF-5 format, but the maintenance terminated. NJOY with 94, 97 and 99 versions corresponds to ENDF-5 and -6 format, and the maintenance continues. The result of covariance data agrees between NJOY and PUFF-2.
Although NJOY has the restriction of resonance parameter processing as follows: i) single energy range, 2) compatible resolved resonance with Breit-Wigner formalisms, 3) MT-pairs of 18-18, 18-102 and 102-102 (18 is fission and 102 is radiative capture), NJOY does not process the angular and energy distributions of covariance data.
2. Development of ERRORJ
Main body of the ERRORJ code [5] adopted the ERRORR module in NJOY94.105.
Thus the function of ERRORR is available to use in ERRORJ. ERRORJ produces a COVFIL format file to store multigroup covariance data and it is converted to a COVERX format file by a conversion program NJOYCOVX. A COVERX format as a standard file of multigroup covariance data is proposed in the FORSS system [6]. Utility programs of viewcvx and editcvx were produced as a viewer and an editor of a COVERX format file. The calculation flow of ERRORJ is shown in Fig. 1.
The feature of ERRORJ is as follows:
1) expanded processing for covariance data of general resolved and unresolved resonance parameters,
2) processing for p. (average cosine of elastic scattering angle) and fission spectrum (%; energy distribution),
3) input method of multigroup cross section constant with various forms,
4) output files with various formats by NJOYCOVX (as COVERX format file, correlation
matrix file, and relative error and standard deviation file).
The processing method of compatible resolved resonance covariance developed in PUFF-2 couldn't be applied to the covariance of general resolved and unresolved resonance parameters. Thus, 1% sensitivity method was newly developed to process these covariance.
The sensitivity coefficient of this method is obtained from the variation of resonance cross section when a resonance parameter is changed with 1 %. The point-wise resonance cross section is used, and the sensitivity coefficient is calculated with group-averaged variation.
This method treats a resonance extended over few energy groups, a negative resonance energy, and total and elastic scattering cross sections. But long calculation time is necessary, and current version doesn't include the treatment of long-range covariance contribution and Adler-Adler resolved resonance parameter.
The covariance processing of p. (average cosine of elastic scattering angle; MT=251) was newly added. It uses multigroup constants of elastic scattering cross sections (MT=2) and p, (MT=251), and covariance of Pj component of elastic scattering (MF=34/MT=2). Other angular distribution isn't processed in current ERRORJ.
The covariance processing of fission energy spectrum (%) was newly added. It uses fission energy spectrum (MF=5/MT=18) and covariance of % (MF=35/MT=18). Other energy distribution isn't processed in current ERRORJ.
3. Confirmation of ERRORJ
To confirm the 1% sensitivity method in resonance parameter processing, the relative covariance of U-238 fission cross sections by the old version of resolved resonance parameter with Breit-Wigner form (JENDL-3.2) was compared with the PUFF-2 method. The compared result is shown in Fig. 2 and both agree as same as radiative capture. The difference in energy range from 2.0347 to 4.3074 [keV] occurs because a resonance must be within an energy group including peak energy of resonance in the PUFF-2 method. The 1% sensitivity method can estimate the effect by the number of groups. It is shown in Fig. 3 compared the standard deviation between VITAMIN-J (neutron 175 group) and JNC-19 group, for covariance of U-235 total cross sections. Both covariances have a good agreement in energy range above 500 eV, but energy range below 100 eV is bad because the range of JNC-19 group is averaged in one group. Thus the fine group structure is necessary in order to reproduce the covariance in resonance region. The relative standard deviation of VITAMIN-J in Fig.3 is equivalent to the predictive value by evaluator. Therefore, the 1 % sensitivity method was confirmed.
The relative standard deviations of U-238 cross sections (total, elastic scattering, fission, and radiative capture) processed with JNC-19 group structure by ERRORJ are shown in Fig. 4. The relative standard deviations of fission spectra (U233, 235, 238, Pu239 and -240) processed with JNC-19 group structure by ERRORJ are shown in Fig. 5. The function of ERRORJ was confirmed through investigation of Fig. 2 to 5 and correlation matrices, by comparison with evaluated data.
4. Summary
The ERRORJ code was produced to process the JENDL covariance data. ERRORJ processed all covariance data evaluated for JENDL-3.2. ERRORJ has new functions of the
1 % sensitivity method for processing resonance parameters and the processing of ft and % data.
In future, ERRORJ will be necessary to add the covariance data processing of angular and energy distributions, and to update the resolved resonance parameter processing of Adler-Adler form and long-range covariance contribution.
JAERI-Conf 2001-009
Acknowledgements
This work was supported by the JNC. The author is very grateful to members of the Covariance Evaluation Working Group for useful help and discussions.
References
[1] Nakagawa T , et al.: "Japanese Evaluated Nuclear Data Library Version 3 Revision-2:
JENDL-3.2," J. Nucl. Sci. Technol., 32, 1259 (1995).
[2] Shibata K., et al.: "JENDL-3.2 Covariance File for Fast Reactors," Proc. Int. Conf.
Nuclear Data for Sci. Technol., Trieste, p904 (1997).
[3] MacFarlane R.E. and Muir D.W.: "The NJOY Nuclear Data Processing System Version 91," LA-12740-M (1994).
[4] Smith, III J.D.: "Processing ENDF/B-V Uncertainty Data into Multigroup Covariance Matrices," ORNL/TM-7221 (1980).
[5] Kosako K. and Yamano N.: "Preparation of a Covariance Processing System for the Evaluated Nuclear Data File, JENDL, (III)," JNC TJ9440 99-003 (1999).
[6] Drischler J.D.: "The COVERX Service Module of the FORSS System," ORNL/TM-7181 (ENDF-291) (1980).
JENDL Nuclear data file
user input /
, .dataL /
Multigroup processing
multigroup file supplied
by user
relative error
& std.dev. file
correlation matrix file Fig. 1 Calculation flow of the ERRORJ
10"
1• 1% sensitivity ---PUFF-2 method
Fig. 2 Relative covariance of U-238 fission cross sections by resolved resonance parameter of JENDL-3.2 produced by ERRORJ with JNC-19 group.
c
o
L resolved resonance region
-••. • • .. "•:
Neutron energy [eV]
Fig.3 Comparison of the relative standard deviation by energy group structure in process of ERRORJ for U-235 total cross section (JENDL-3.2).