Nuclear Reactor Design pp 1-47 | Cite as

# Fuel Burnup and Reactivity Control

## Abstract

Nuclear fuel burnup and reactivity control are important points in the core design of nuclear reactors.

The fuel burnup analysis generally evaluates the time-dependent core power distribution and reactivity by solving burnup equations for the atomic density change of nuclides contained in the fuel as well as solving multi-group diffusion equations for neutron flux distribution and effective neutron multiplication factor. The core power distribution is necessary information for thermal-hydraulic and fuel designs.

The core design for reactivity control predicts reactivity change during reactor operation and determines its optimal control methods based on calculations of reactivity change with fuel burnup, fission product (FP) accumulation (poisoning effect), inherent reactivity feedback by temperature changes of fuel and coolant, etc. Among the general methods available for reactivity control, the insertion and withdrawal of neutron absorbers, generally referred to as control rods, is the approach usually taken for power reactors. A burnable poison, (a nuclide that has a large neutron absorption cross section) or a chemical shim (a neutron-absorbing chemical, usually boric acid, which is concentrated in the moderator or coolant) is employed for reactivity control depending on reactor types.

Fuel burnup and reactivity control based on fundamental theories with numerical expressions will be briefly reviewed in this chapter.

## Keywords

Temperature Coefficient Neutron Flux Absorption Cross Section Reactivity Change Fuel Burnup## References

- 1.Suyama K, Katakura J, Ohkawachi Y, Ishikawa M (1999) Libraries based on JENDL-3.2 for ORIGEN2 code: ORLIBJ32, JAERI-Data/Code 99-003. Japan Atomic Energy Research Institute (in Japanese)Google Scholar
- 2.Horiguchi T, Tachibana T, Koura H, Katakura J (2004) Chart of the nuclides 2004. Japanese Nuclear Data Committee, Japan Atomic Energy Research InstituteGoogle Scholar
- 3.Bateman H (1910) The solution of a system of differential equations occurring in the theory of radio-active transformations. Proc Cambridge Philos Soc 15:423Google Scholar
- 4.Knief RA (1992) Nuclear engineering. Taylor and Francis, BristolGoogle Scholar
- 5.Sugi T (1994) Nuclear reactor training lecture text: nuclear reactor physics. Japan Atomic Energy Research Institute, pp 119–124 (in Japanese)Google Scholar
- 6.Jakeman D (1966) Physics of nuclear reactors. The English Universities Press, LondonGoogle Scholar
- 7.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 13.2. Addison-Wesley, ReadingGoogle Scholar
- 8.Tasaka K et al (1990) JNDC nuclear data library of fission products, -second version-, JAERI 1320. Japan Atomic Energy Research InstituteGoogle Scholar
- 9.Duderstadt JJ, Hamilton LJ (1976) Nuclear reactor analysis, section 15-I. Wiley, New YorkGoogle Scholar
- 10.Duderstadt JJ, Hamilton LJ (1976) Nuclear reactor analysis, section 14-IV. Wiley, New YorkGoogle Scholar
- 11.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 14-1. Addison-Wesley, ReadingGoogle Scholar
- 12.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 14-2. Addison-Wesley, ReadingGoogle Scholar
- 13.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 14-7. Addison-Wesley, ReadingGoogle Scholar
- 14.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 13-1. Addison-Wesley, ReadingGoogle Scholar
- 15.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 11-3. Addison-Wesley, ReadingGoogle Scholar
- 16.Duderstadt JJ, Hamilton LJ (1976) Nuclear reactor analysis, section 14-V. Wiley, New YorkGoogle Scholar
- 17.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 11-2. Addison-Wesley, ReadingGoogle Scholar
- 18.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 8-2. Addison-Wesley, ReadingGoogle Scholar
- 19.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 8-1. Addison-Wesley, ReadingGoogle Scholar
- 20.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 9-6. Addison-Wesley, ReadingGoogle Scholar
- 21.Sugi T (1994) Nuclear reactor training lecture text: nuclear reactor physics. Japan Atomic Energy Research Institute, pp 159–162 (in Japanese)Google Scholar
- 22.Togo Y, Ishikawa M, Shiba M (1977) Document collection of safety measures in postulated accidents of light water reactors. ISU Inc., Japan (in Japanese)Google Scholar
- 23.Lewins J (1965) Importance: the adjoint function. Pergamon, OxfordGoogle Scholar
- 24.Otsuka M (1972) Nuclear reactor physics. Kyoritsu, Tokyo (in Japanese)Google Scholar
- 25.Bell GI, Glasstone S (1970) Nuclear reactor theory, section 6-1. Van Nostrand Reinhold Co., New YorkGoogle Scholar
- 26.Lamarsh JR (1966) Introduction to nuclear reactor theory, section 15–6. Addison-Wesley, ReadingGoogle Scholar
- 27.Japan Atomic Energy Agency (2007) The 38th nuclear reactor chief engineer examination (in Japanese)Google Scholar