ASTM E321-1996(2012)
铀和钚燃料中原子裂变百分比的标准试验方法(钕-148法)
Standard Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Neodymium-148 Method)
ASTM E321-1996(2012) 中，可能用到以下耗材
- 标准号
- ASTM E321-1996(2012)
- 发布日期
- 1996年
- 实施日期
- 废止日期
- 无
- 中国标准分类号
- F46
- 国际标准分类号
- 27.120.30 (Fissile materials and nuclear fuel tech
- 发布单位
- US-ASTM
- 适用范围
The burnup of an irradiated nuclear fuel can be determined from the amount of a fission product formed during irradiation. Among the fission products, 148Nd has the following properties to recommend it as an ideal burnup indicator: (1) It is not volatile, does not migrate in solid fuels below their recrystallization temperature, and has no volatile precursors. (2) It is nonradioactive and requires no decay corrections. ( 3) It has a low destruction cross section and formation from adjacent mass chains can be corrected for. (4) It has good emission characteristics for mass analysis. (5) Its fission yield is nearly the same for 235U and 239Pu and is essentially independent of neutron energy (6). (6) It has a shielded isotope, 142Nd, which can be used for correcting natural Nd contamination. (7) It is not a normal constituent of unirradiated fuel.
The analysis of 148Nd in irradiated fuel does not depend on the availability of preirradiation sample data or irradiation history. Atom percent fission is directly proportional to the 148Nd-to-fuel ratio in irradiated fuel. However, the production of 148Nd from 147Nd by neutron capture will introduce a systematic error whose contribution must be corrected for. In power reactor fuels, this correction is relatively small. In test reactor irradiations where fluxes can be very high, this correction can be substantial (see Table 1).
The test method can be applied directly to U fuel containing less than 0.5 % initial Pu with 1 to 100 GW days/metric ton burnup. For fuel containing 5 to 50 % initial Pu, increase the Pu content by a factor of 10 to 100, respectively in both reagents 5.3 and 5.4.
TABLE 1 K Factors to Correct 148Nd for 147Nd Thermal Neutron CaptureA
Total Neutron Flux,
x03D5; (neutrons/cm2/s)Total Neutron Exposure, x03D5;I (neutrons/cm 2) 1 x00D7; 10 20 3 x00D7; 10 20 1 x00D7; 10 21 2 x00D7; 10 21 3 x00D7; 10 21 3 x00D7; 101 2 0.9985 0.9985 0.9985 0.9985 0.9985 1 x00D7; 101 3 0.9956 0.9952 0.9950 0.9950 0.9950 3 x00D7; 101 3 0.9906
ASTM E321-1996(2012) 中可能用到的仪器设备
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