Physics of plutonium recycling. 6 : a report by the working party on the physics of plutonium recycling of the NEA Nuclear Science Committee : Multiple Pu recycling in advanced PWRs

162 Pages·2002·0.983 MB·English

by  OECD

Nuclear Science
Physics of Plutonium Recycling
Volume VI
Multiple Pu Recycling in Advanced PWRs
NUCLEAR ENERGY AGENCY
ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT
ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT
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economic development; and
− to contribute to the expansion of world trade on a multilateral, non-discriminatory basis in accordance with
international obligations.
The original Member countries of the OECD are Austria, Belgium, Canada, Denmark, France, Germany, Greece,
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Kingdom and the United States. The following countries became Members subsequently through accession at the dates
indicated hereafter: Japan (28th April 1964), Finland (28th January 1969), Australia (7th June 1971), New Zealand (29th
May 1973), Mexico (18th May 1994), the Czech Republic (21st December 1995), Hungary (7th May 1996), Poland (22nd
November 1996), Korea (12th December 1996) and the Slovak Republic (14 December 2000). The Commission of the
European Communities takes part in the work of the OECD (Article 13 of the OECD Convention).
NUCLEAR ENERGY AGENCY
The OECD Nuclear Energy Agency (NEA) was established on 1st February 1958 under the name of the OEEC
European Nuclear Energy Agency. It received its present designation on 20th April 1972, when Japan became its first
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Agency.
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© OECD 2002
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FOREWORD
The OECD/NEA Working Party on the Physics of Plutonium Fuels and Innovative Fuel Cycles
(WPPR) was established in 1993 and reports to the OECD/NEA Nuclear Science Committee. Its main
activity has been to analyse physics code benchmarks for problems related to the physics of plutonium
fuels. Past volumes of published work have examined the physics of plutonium-fuelled pressurised
water reactors (PWRs), as well as the physics of metal- and oxide-fuelled fast reactors.
Some of the questions that the Working Group has attempted to address in the present and
previous volumes include:
• What is the effect on the physics of the degradation in plutonium fissile quality that occurs
with increasing burn-up and age of spent fuel?
• What is the impact on the physics of multiple recycling of plutonium if MOX assemblies
are themselves reprocessed? What are the limitations associated with multiple recycling? Is
there a point beyond which multiple recycling becomes no longer practicable in the present
generation of PWRs?
• Are the present nuclear data libraries and neutronics codes capable of predicting the physics
performance of MOX made from plutonium derived from high burn-up and/or multiple-
recycling scenarios?
• Is thermal MOX recycling ultimately compatible with a fast-reactor fuel cycle? Can fast
reactors be used in a flexible manner to address whatever requirements there might be to
consume plutonium from a thermal MOX programme? Can plutonium-burning fast reactors
be changed to plutonium breeding to maintain self-sufficiency in the longer term?
• How do the nuclear codes compare with real data from experiments?
The “Physics of Plutonium Recycling” series currently comprises the following titles:
• Volume I: Issues and Perspectives (OECD/NEA, 1995);
• Volume II: Plutonium Recycling in Pressurised Water Reactors (OECD/NEA, 1995);
• Volume III: Void Reactivity Effect in Pressurised Water Reactors (OECD/NEA, 1995);
• Volume IV: Fast Plutonium Burner Reactors: Beginning of Life (OECD/NEA, 1995);
• Volume V: Plutonium Recycling in Fast Reactors (OECD/NEA, 1996);
• Volume VI: Multiple Plutonium Recycling in Advanced PWRs (OECD/NEA, 2002).
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Volumes VII and VIII, in preparation, will be devoted to a theoretical benchmark of a boiling
water reactor (BWR) assembly containing mixed-oxide fuel rods, and to plutonium fuel in high-
temperature reactors.
While all of the earlier work consisted of theoretical benchmarks comparing different nuclear
codes and nuclear data libraries, comparisons against experimental measurements were made possible
by SCK-CEN using data from the VENUS-2 reactor. The VENUS-2 data concerned an experimental
mock-up of a PWR core containing UO and mixed-oxide (MOX) assemblies. The results of this
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benchmark were published in Benchmark on the VENUS-2 MOX Core Measurements (OECD/NEA,
2000). The benchmark was carried out under the joint auspices of the WPPR and the Task Force on
Reactor-based Plutonium Disposition (TFRPD). Another benchmark was undertaken for three critical
core configurations of the KRITZ reactor: two with UO fuel and one with MOX fuel. Measurements
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were performed for room temperature as well as elevated temperatures (~245°C). The results are due
to be published soon.
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TABLE OF CONTENTS
FOREWORD................................................................................................................................. 3
CONTRIBUTORS......................................................................................................................... 7
BENCHMARK PARTICIPANTS............................................................................................... 8
EXECUTIVE SUMMARY........................................................................................................... 9
Chapter 1. INTRODUCTION....................................................................................................... 11
Chapter 2. BENCHMARK SPECIFICATION........................................................................... 15
Chapter 3. PARTICIPANTS AND METHODS.......................................................................... 27
Chapter 4. PRESENTATION OF RESULTS............................................................................. 29
Annex to Chapter 4 – Energy per reaction................................................................... 75
Chapter 5. DISCUSSION AND INTERPRETATION OF RESULTS...................................... 79
Chapter 6. RESULTS OF THE SPECIAL BENCHMARK ON PWR MOX PIN CELLS.... 89
Annex 1 to Chapter 6 – Specifications of the new benchmark to compare
MCNP, WIMS, APPOLLO2, CASMO4 and SRAC................. 111
Annex 2 to Chapter 6 – Effect of different state-of-the-art nuclear data libraries
on the PWR MOX pin cells benchmark of Chapter 6............. 113
Chapter 7. CONCLUSIONS......................................................................................................... 115
REFERENCES.............................................................................................................................. 117
APPENDIX A – Phase II – Benchmark specification................................................................... 119
APPENDIX B – List of participants (addresses)........................................................................... 143
APPENDIX C – List of symbols and abbreviations...................................................................... 151
APPENDIX D – Corrigendum for previous volumes.................................................................... 153
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CONTRIBUTORS
CHAIR K. Hesketh BNFL UK
SECRETARY E. Sartori OECD/NEA
PRINICPAL AUTHORS M. Delpech CEA France
K. Hesketh BNFL UK
D. Lutz IKE Germany
E. Sartori OECD/NEA
PROBLEM SPECIFICATION M. Delpech CEA France
SPECIAL CONTRIBUTION G. Schlosser Siemens/KWU Germany
DATA COMPILATION AND ANALYSIS M. Delpech CEA France
I. Champtiaux CEA France
M. Goutefarde CEA France
M. Juanola CEA France
SPECIAL STUDY (CHAPTER 6) S. Cathalau CEA France
D. Lutz IKE Germany
W. Bernnat IKE Germany
M. Mattes IKE Germany
T.T.J. M. Peeters ECN The Netherlands
Y. Peneliau CEA France
A. Puill CEA France
H. Takano JAERI Japan
EDITOR K. Hesketh BNFL UK
TEXT PROCESSING AND LAYOUT A. McWhorter OECD/NEA
H. Déry OECD/NEA
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BENCHMARK PARTICIPANTS
Name Establishment Country
MALDAGUE, Thierry Belgonucléaire Belgium
HOEJERUP C. Frank Risø Denmark
BARBRAULT Patrick EDF-Clamart France
VERGNES Jean EDF-Clamart
DELPECH Marc CEA-Cadarache
COSTE Mireille CEA-Saclay
LEE Yi-Kang CEA-Saclay
PENELIAU Yannick CEA- Saclay
PUILL André CEA- Saclay
ROHART Michelle CEA- Saclay
TSILANIZARA Aimé CEA- Saclay
POINOT-SALANON Christine FRAMATOME
HESSE Ulrich GRS Germany
MOSER Eberhard GRS
LEHMANN Sven U-Braunschweig
BERNNAT Wolfgang U-Stuttgart-IKE
LUTZ Dietrich U- Stuttgart -IKE
MATTES Margerete U- Stuttgart -IKE
SCHWEIZER M. U- Stuttgart -IKE
KANEKO K. ITIRO Japan
AKIE Hiroshi JAERI
TAKANO Hideki JAERI
MISAWA Tsuyoshi U-Nagoya
TAKEDA Toshikazu U-Osaka
YAMAMOTO Toshihisa U-Osaka
FUJIWARA Daisuke U-Tohoku
IWASAKI Tomohiko U-Tohoku
KIM Young-Jin KAERI Republic of Korea
KLOOSTERMAN Jan Leen Petten The Netherlands
TSIBOULIA Anatoli IPPE-Obninsk Russian Federation
PARATTE Jean-Marie PSI Switzerland
CROSSLEY Steve BNFL United Kingdom
HESKETH Kevin BNFL
BLOMQUIST Roger N. ANL USA
GRIMM Karl ANL
HILL Robert N. ANL
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EXECUTIVE SUMMARY
The recycling of plutonium in LWRs has for quite some time been seen as an important interim
step prior to the large scale introduction of fast reactors; several countries have, in fact, been using
MOX fuel in PWRs on a commercial scale for many years. Now that fast reactors are no longer
expected to be introduced for some time, the need to manage existing plutonium stocks puts even
more emphasis on LWR MOX. Even though there is sufficient experience of MOX in PWRs to be
assured of satisfactory performance under existing conditions, the situation is not static and it is very
important to address future requirements.
There are two main trends which need to be accounted for. First, discharge burn-ups are still
increasing steadily. Second, the fissile quality of the plutonium is generally becoming poorer.
The decline in fissile quality is partly a consequence of the higher burn-ups, but another major
consideration is the effect of recycling MOX fuel itself. Multiple recycle scenarios cause a significant
decline in fissile quality in each recycle generation. One consequence is that the initial plutonium
content of MOX fuel is considerably increased in each recycle generation and this poses
a considerable challenge to current nuclear design codes and the associated nuclear data libraries.
The OECD Working Group on the Physics of Plutonium Recycling (WPPR) has considered the
issue of multiple recycle of MOX in PWRs in Volumes I and II of its report published in 1995.
The main effort was directed towards an international benchmark exercise in which participants were
invited to submit solutions to a fully defined problem representative of a multiple recycle scenario in
a PWR. Such benchmark exercises are a valuable first step towards understanding the problems to be
overcome before a future scenario can be realised in practice. They cannot, of course, identify the
correct answer; this must wait until there is experimental or operational experience to learn from.
However they can highlight the areas in which current calculational methods and nuclear data start
to breakdown and thereby provide a rational basis for directing the research effort.
The earlier benchmark work identified major discrepancies between the various nuclear design
codes and nuclear data libraries, specifically differences of up to 4%∆k in reactivities. A portion of
the range of discrepancy was explained because some of the codes did not apply self-shielding to the
resonance treatment of the higher plutonium isotopes; with the large concentration of 242Pu specified
in the benchmark, self-shielding in this nuclide was very important. Nevertheless the remaining
discrepancy was considered sufficiently large that further work would clearly be necessary before the
multiple recycle scenario envisaged in the specification could be implemented.
A shortcoming of the initial benchmark was that the cases considered only included one
corresponding to today’s situation (with plutonium of good isotopic quality), to one which might arise
after many generations of MOX recycle (with extremely poor isotopic quality). Analysis of the
intermediate steps was missing, and therefore there was no possibility of determining precisely where
the nuclear codes and data libraries would start to lose their applicability. Accordingly, CEA
suggested a benchmark in which five consecutive generations of multiple recycle in a PWR would
be followed. In the specification of the benchmark, attempts were made to make it as realistic a
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