Application of MCNP5 in power distribution calculations of solid fuel molten salt reactor
-
摘要: 采用蒙特卡罗输运程序MCNP5对固态燃料熔盐实验堆(TMSR-SF1)能量沉积比例及功率分布进行了计算分析。针对MCNP5不能处理缓发β及缓发γ的能量沉积问题进行了类比等效处理。对固态燃料熔盐实验堆在寿期初、寿期中、寿期末相应的能量沉积比例及功率分布进行了研究。通过计算发现,固态燃料熔盐实验堆内燃料球相比于压水堆棒状燃料元件(95%~97%左右)而言,能量沉积比例有所偏小,约为93%。同时,由于堆芯功率分布均匀,功率峰因子较小(约1.5),堆芯安全性较好。Abstract: A Monte Carlo Code MCNP5 is used to analyse the energy deposition ratio and power distribution in thorium-based molten salt experiment reactor with solid fuel (TMSR-SF1). Since MCNP5 could not deal with the deposition energy from delayed beta and gamma ray photons, an analog equivalent method is used to take them into account. Then, the energy deposition rate and power distribution in TMSR-SF1 are calculated during the beginning, the middle and the end of the reactor life cycle. The results indicate that, compared with the PWR fuel rod (which is about 95%-97%), the energy deposition ratio in the pebble of TMSR-SF1 is smaller (about 93%). At the same time, TMSR-SF1 behaves good safety feature due to its low power peak factor (about 1.5).
-
Key words:
- solid fuel molten salt reactor /
- fuel pebble /
- energy deposition /
- power peaking factor
-
表 1 铀-235核裂变能
Table 1. Fission energy comes from U-235
energy form energy released/MeV range emission time fission fragments 167 very short,≈10-3 cm prompt fission neutron 5 secondary, 10~100 cm prompt γ ray from prompt fission 7 long,≈100 cm prompt β ray from fission products 7 short, several mm delayed γ ray from fission products 8 long,≈100 cm delayed neutrino 12 very long delayed total 207 表 2 统计卡计数值比较
Table 2. Comparison of calculated values of statistical cards
region F4:n F4:p
bremsstrahlung onF4:p
bremsstrahlung offF6:n F6:p F6:np fuel pebble 70.657 2.648 2.628 70.657 2.626 73.292 coolant 0.457 1.080 1.075 0.457 1.075 1.531 reflector 0.215 1.035 1.020 0.215 1.021 1.235 core barrel 0.000 0.353 0.339 0.000 0.338 0.338 control rod 0.028 0.184 0.181 0.028 0.181 0.210 total 71.357 5.301 5.244 71.357 5.240 76.606 表 3 有无修正下的统计卡计数值比较
Table 3. Comparison of calculated values of statistical cards with or without corrections
material fission kinetic energy
and neutron deposition/%photon
deposition/%total energy
deposition/%fission kinetic energy
and neutron deposition/%photon
deposition/%total energy
deposition/%F6:np, direct statistical result F6:np, considering delayed photon and beta fuel kernel 91 0.9 91.8 85.7 1.5 87.3 graphite matrix 0.7 1.5 2.2 0.7 2.7 3.4 graphite shell 0.5 1.1 1.6 0.5 1.9 2.4 total 95.6 93.0 coolant 0.6 1.4 2.0 0.5 2.5 3.1 reflector 0.3 1.3 1.6 0.2 2.3 2.6 core barrel 0 0.4 0.4 0 0.8 0.8 control rod 0 0.24 0.3 0 0.4 0.5 表 4 不同寿期固态燃料熔盐实验堆能量沉积分布
Table 4. Energy deposition distribution with different period of lifetime
region R at beginning of core-life
with xenon equilibrium/%R at middle of
core-life/%R at end of
core-life/%fuel pebble 93.0 92.9 92.8 coolant 3.1 3.1 3.1 reflector 2.6 2.6 2.7 core barrel 0.8 0.9 1.0 control rod 0.5 0.4 0.3 表 5 不同寿期功率峰因子及轴向偏移比较
Table 5. Comparison of peak power factor and axial offset in different period of lifetime
period peak factor of
radial directionpeak factor of
axial directionpeak factor of
total poweraxial deviation
AO/%no xenon at
beginning of life1.26 1.23 1.55 11.77 xenon equilibrium at
early stage of life1.20 1.25 1.5 13.82 middle of life 1.18 1.24 1.47 9.14 end of life 1.15 1.24 1.44 1.55 -
[1] 江绵恒, 徐洪杰, 戴志敏. 未来先进核裂变能——TMSR核能系统[J]. 中国科学院院刊, 2012, 27(3): 366-374. https://www.cnki.com.cn/Article/CJFDTOTAL-KYYX201203017.htmJiang Mianheng, Xu Hongjie, Dai Zhimin. Advance fission energy program—TMSR nuclear energy system. Bulletin of the Chinese Academy of Sciences, 2012, 27: 366-374 https://www.cnki.com.cn/Article/CJFDTOTAL-KYYX201203017.htm [2] Hosking J G, Newton T D. Results of a benchmark considering a high-temperature reactor (HTR) fuelled with reactor-grade plutonium[R]. Paris: OECD, 2007. [3] Peterson J L, Ilas G. Calculation of heating values for the high flux isotope reactor[C]//PHYSOR 2012—Advances in Reactor Physics. [4] Yang W S, Taiwo T A. Status of reactor analysis methods and codes in the U.S. A[C]//Chicago: PHYSOR 2004. [5] Hollenbach D F, Petrie L M, Landers N F. KENO-VI: A general quadratic version of the KENO program[R]. ORNL/TM-2005/39, Version 5, Vol. Ⅱ, Oak Ridge National Laboratory(Apr. 2005). [6] X-5 Monte Carlo Team. MCNP5—A general Monte Carlo N-particle transport code[R]. Version 5, Volume Ⅱ: Uses' guide, LA-CP-03-0245, Los Alamos National Laboratory (2003). [7] DOE Fundamentals Handbook. Nuclear Physics and Reactor Theory Volume 1 of 2[K]. DOE-HDBK-1019/1-93. 1993. [8] 曹栋兴. 核反应堆设计原理[M]. 北京: 原子能出版社, 1992.Cao Dongxing. Elements of nuclear reactor design. Beijing: Atomic Energy Press, 1992 [9] 谢仲生, 尹邦华, 潘国品, 等. 核反应堆物理分析[M]. 北京: 原子能出版社, 1985.Xie Zhongsheng, Yin Banghua, Pan Guopin, et al. Nuclear reactor physics analysis. Beijing: Atomic Energy Press, 1985 [10] Brown F B, Mosteller R D, Martin W R. Monte Carlo—advances and challenges[C]//PHYSOR'08. Monte Carlo Workshop. 2008.