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Nuclear Fission Reactor
Published in C. K. Gupta, Materials in Nuclear Energy Applications, 1989
The first swimming pool reactor, named Bulk Shielding Reactor (BSR), was constructed at the Oak Ridge National Laboratory. The reactor is operated by the control movement of three cadmium safety rods driven by motors on the supporting bridge structure spanning the pool. Electromagnets keep these rods suspended above the core during operation. In case of emergency, the current to the electromagnets is decreased and the safety rods drop in the reactor to shut it down. This type of reactor has proven itself to be a versatile research tool, and as a result, many of these installations have been constructed, incorporating various improvements over the original BSR. Many of these reactors incorporate three or four safety rods which contain boron carbide and are suspended above the core by electromagnets. In addition, there is a stainless-steel control rod which is used for fine control of the reactor. Beam tubes pierce the concrete walls of the pool and establish contact with the core.
Post-Neutron Mass Yield Distribution in the Epi-Cadmium Neutron–Induced Fission of 238Pu
Published in Nuclear Science and Engineering, 2023
H. Naik, R. J. Singh, S. P. Dange, W. Jang
Two different types of experiments were carried out using the reactor APSARA at Bhabha Atomic Research Centre (BARC), India. For relatively short-lived fission products, 100 μL of nitrate solutions of 238Pu (50 μg/mL) were sealed in three different polypropylene tubes of about 2-cm length and 3-mm inner diameter. The individual targets were doubly sealed in alkathene bags and wrapped separately with 1-mm-thick Cd foils. They were kept separately inside three different plastic bottles and irradiated one at a time for 10 to 11 min in the highly enriched uranium–fueled light water–moderated swimming pool reactor APSARA at a flux of 1.2 × 1012 n∙cm−2∙s−1.[23] After the irradiations, the irradiated solutions inside the polypropylene tubes were mounted on different Perspex plates without opening the tubes.
Post-Neutron Mass Yield Distribution in the Epi-Cadmium Neutron-Induced Fission of 229Th
Published in Nuclear Science and Engineering, 2023
H. Naik, R. J. Singh, S. P. Dange, W. Jang
The present experiment is similar to the epi-cadmium neutron-induced fission of 229Th as studied earlier30 but with a slight difference in fission product collection. An electrodeposited target of 229Th (~100 μg) was covered with 75-μm-thick Lexan foil instead of 25-μm-thick aluminum foil. The Lexan foil acts as a catcher to collect the recoiling fission products during the neutron irradiation of the target. This is to remove the possible contamination of alpha active 229Th and to avoid the constant gamma-ray background of its daughter products. The Lexan catcher foil instead of Al foil was used to avoid possible activation products from the 27An(n,α)24Na reaction. The samples were wrapped with 1-mm-thick cadmium foil and doubly sealed in alkathene bags. They were then irradiated for 15 to 60 min with a flux of 1.2 × 1012 n·cm−2·s−1 in the highly enriched uranium–fueled light water–moderated swimming pool reactor APSARA (Refs. 20 and 30). After the irradiations, the Lexan catcher foils containing the fission products were taken out from the irradiated targets, folded to make pointlike sources, and then mounted on different Perspex plates.
Post-Neutron Mass Yield Distribution in the Epi-Cadmium Neutron-Induced Fission of 241Am
Published in Nuclear Science and Engineering, 2022
H. Naik, S. P. Dange, W. Jang, R. J. Singh
For relatively long-lived fission products, an electrodeposited target of 241Am (~100 μg) was covered with 75-μm-thick Lexan foil or 25-μm-thick Al foil. The Lexan and Al foils acted as a catcher to collect the recoiling fission products during neutron irradiation of the target. The sample was then wrapped with 1-mm-thick cadmium foil and doubly sealed in alkathene bags. It was then irradiated for 30 to 60 min at a flux of 1.2 × 1012 n‧cm−2‧s−1 in the highly enriched uranium–fueled light water–moderated swimming pool reactor APSARA (Ref. 22). Because of its thermal fission cross section of 3.15 b, the cadmium wrapper prevented thermal neutron–induced fission of 241Am. After the irradiation, the Lexan catcher foil was taken out from the irradiated target and washed with very dilute nitric acid and subsequently with distilled water. This was to remove possible contamination of the alpha active 241Am target. The Lexan catcher containing the fission products was folded to make a pointlike source and then mounted on a Perspex plate. On the other hand, the Al catcher from the irradiated electrodeposited target was used for radiochemical separation22,23 of fission products such as tellurium and iodine isotopes. The 5-mL aliquots of separated solution of tellurium or iodine samples inside individual counting vials were mounted on vial holders attached to different Perspex plates.