Neutron source holders

The core plate consists of a circular plate with round openings. The core plate provides horizontal support and guidance for the control rod guide tubes, incore flux monitor tubes, peripheral fuel supports, and startup neutron source holders. The last two items are also supported vertically by the core plate. The entire assembly is bolted to a support ledge in the core shroud. The core plate also forms a portion within the core shroud, which causes the recirculation flow to pass into the orificed fuel support and through the fuel assemblies. 

Reflector elements, safety blades, regulating blade, neutron source and holder, scram times and method of measurement of drop times. 

Figure 18.4 A sketch of thecross-section of the drum (a) enclosing the neutron source. The wooden holder (b) is shown on the right.

Density and Moisture Tester (MC-l). A 50 mCi mixture of Americium-241 and Beryllium is located within the base of the MC-l (about 200 times more than is used in the M43A1 Chemical Agent Detector). Neutron emission occurs when an alpha particle emitter such as Americium-241 is mixed with Beryllium (Be) powder in a tightly compressed pellet. The MC-l also has a 10 mCi Cesium-137 source located in a probe tip used to determine the density of the soil at a construction site. This source is classified as a special form source and is double-encapsulated in stainless steel. TACOM is the NRC license holder for the MC-l and is responsible for item management. 

The shielding tank facility, located on the south side of the reactor, will be utilized for this experiment. A plane source of fission neutrons will be generated by a number of Argonaut fuel plates (Fig. 20.2). The detecting devices are indium foils 1.9 cm in diameter, 80 mg-cm enclosed in 0.0457-cm-thick (18/mil) cadmium cans (Fig. 20.4). These foils will be mounted on a holder provided (Fig. 20.3). A pair of gold foils may be used for monitor foils and to determine the Au-Cd ratio if desired. 

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