{"id":18603,"date":"2018-09-10T15:07:09","date_gmt":"2018-09-10T15:07:09","guid":{"rendered":"http:\/\/sitepourvtc.com\/?page_id=18603"},"modified":"2023-02-07T09:20:15","modified_gmt":"2023-02-07T09:20:15","slug":"xenon-135","status":"publish","type":"page","link":"https:\/\/sitepourvtc.com\/nuclear-power\/reactor-physics\/reactor-operation\/xenon-135\/","title":{"rendered":"Xenon 135"},"content":{"rendered":"
Xenon-135<\/strong> is a product of U-235 fission<\/a> and has a very large <\/strong>neutron capture cross-section<\/strong><\/a> (about 2.6 x 10<\/strong>6<\/sup><\/strong> barns<\/strong>). Due to this cross-section, xenon 135<\/strong> has a tremendous impact on the operation of a nuclear reactor.<\/div><\/div>\n

Xenon<\/strong> is a naturally-occurring chemical element with atomic number 54, which means there are 54 protons and 54 electrons in the atomic structure. The chemical symbol for xenon is Xe<\/strong>. Xenon<\/strong> is a colorless, dense, odorless noble gas found in the Earth\u2019s atmosphere in trace amounts.<\/p>\n

Xenon<\/strong> was first discovered in 1898 by the Scottish chemist William Ramsay and English chemist Morris Travers. The name xenon for this gas comes from the Greek word \u03be\u03ad\u03bd\u03bf\u03bd [xenon], neuter singular form of \u03be\u03ad\u03bd\u03bf\u03c2 [xenos], meaning ‘foreign(er)’, ‘strange(r)’, or ‘guest’.<\/p>\n

Natural xenon consists of eight stable isotopes<\/strong>, 124<\/sup>Xe (0.095%), 126<\/sup>Xe (0.089%), 128<\/sup>Xe (1.91%), 129<\/sup>Xe (26.4%), 130<\/sup>Xe (4.07%), 131<\/sup>Xe (21.23%), 132<\/sup>Xe (26.91%), \u00a0134<\/sup>Xe (10.44%), and one isotope with very long half-life 136<\/sup>Xe (8.86%).<\/p>\n

In the nuclear industry, especially artificial xenon 135<\/strong> has a tremendous impact on the operation of a nuclear reactor<\/a>. It is important for physicists and reactor operators to understand the mechanisms that produce and remove xenon from the reactor to predict how the reactor will respond following changes in power level.<\/p>\n

Another important isotope is xenon 133<\/strong>, which has a half-life of 5.2 days, and its presence in a reactor coolant indicates (together with xenon 135) a possible failure of fuel cladding. A new defect will often result in a step increase in only the Xe-133 activity measured from reactor coolant. As the defect enlarges, the release rate of the soluble, longer-lived nuclides, particularly I-131, I-134, Cs-134, and Cs-137, will increase.<\/p>\n

Xenon 135<\/h2>\n
\"Xenon<\/a>
Xenon – 135. Neutron absorption and scattering. Comparison of cross-sections.
Source: JANIS (Java-based Nuclear Data Information Software); The JEFF-3.1.1 Nuclear Data Library<\/figcaption><\/figure>\n

As was written, xenon 135<\/strong> has a tremendous impact on the operation of a nuclear reactor. Xenon-135<\/strong> is a product of U-235 fission<\/a> and has a very large <\/strong>neutron capture cross-section<\/strong><\/a> (about 2.6 x 10<\/strong>6<\/sup><\/strong> barns<\/strong>). It also decays radioactively with a half-life of 9.1 hours<\/strong>. Little Xe-135<\/strong> results directly from fission, but most comes from the decay chain<\/strong>, Te-135 (\u03b2–<\/sup> decay, 19 sec) to I-135 (\u03b2–<\/sup> decay, 6.6 hr<\/strong>) Xe-135. The instantaneous production rate of xenon 135 is dependent on the iodine 135 concentration and, therefore, on the local neutron flux history. On the other hand, the destruction rate of xenon 135 is dependent on the instantaneous local neutron flux. Its significance is primarily caused by two factors:<\/p>\n