{"id":264051,"date":"2025-07-21T10:49:29","date_gmt":"2025-07-21T10:49:29","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=264051"},"modified":"2025-07-21T10:49:31","modified_gmt":"2025-07-21T10:49:31","slug":"suppose-you-are-in-charge-of-a-fission-nuclear-reactor-and-you-notice-that-the-amount-of-xenon-135-in-the-reactor-core-has-built-up-to-the-extent-that-it-is-compromising-the-operation-of-the-reactor","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/21\/suppose-you-are-in-charge-of-a-fission-nuclear-reactor-and-you-notice-that-the-amount-of-xenon-135-in-the-reactor-core-has-built-up-to-the-extent-that-it-is-compromising-the-operation-of-the-reactor\/","title":{"rendered":"Suppose you are in charge of a fission nuclear reactor, and you notice that the amount of xenon-135 in the reactor core has built up to the extent that it is compromising the operation of the reactor"},"content":{"rendered":"\n

Suppose you are in charge of a fission nuclear reactor, and you notice that the amount of xenon-135 in the reactor core has built up to the extent that it is compromising the operation of the reactor. What factor(s) could this build-up be due to? Select one or more: a. The water level was allowed to drop too low b. The control rods were removed too far c. Running the reactor at too low a power level d. The fuel rods have reached their end of life<\/p>\n\n\n\n

The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n

The correct answer is c. Running the reactor at too low a power level<\/strong>.<\/p>\n\n\n\n

Explanation:<\/strong>
Xenon-135 (Xe-135) is a byproduct of nuclear fission and acts as a strong neutron absorber. It is produced when iodine-135 (I-135) undergoes neutron capture and decays to xenon-135. Normally, xenon-135 is transitory because it decays relatively quickly (with a half-life of about 9.2 hours). However, its buildup can be problematic under certain conditions.<\/p>\n\n\n\n

When the reactor operates at low power levels, the rate of production of iodine-135 is reduced. However, the rate of decay of xenon-135 remains constant. As a result, xenon-135 accumulates faster than it can be consumed in the reaction, leading to the phenomenon known as “xenon poisoning.” This buildup of xenon-135 can absorb neutrons that are critical for sustaining the fission chain reaction, thus impeding the reactor’s ability to operate efficiently.<\/p>\n\n\n\n

The other options do not directly cause xenon-135 buildup:<\/p>\n\n\n\n