151. Operational characteristics of the helium refrigeration system at HANARO-CNS
- Author
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Mun Lee, Wu Jung Son, Sung Hwan Cho, Guk Hoon Ahn, In-Cheol Lim, Ho Young Choi, Min Su Kim, Jae Sam Han, and Soon Ock Hur
- Subjects
chemistry ,Nuclear engineering ,Mechanical engineering ,chemistry.chemical_element ,Refrigeration ,Neutron source ,Neutron ,Research reactor ,Helium-3 refrigerator ,Helium ,Liquid hydrogen ,Gas analyzer - Abstract
The HANARO research reactor produced the first cold neutron sources through the neutron guide tube on Nov 3. 2009. Cold sources are produced by scattering method in the moderator cell that is filled with liquid hydrogen to maintain a sub-cooled state by a helium refrigeration system (HRS). The helium refrigerator has a capacity of 1500 watts at a supply temperature of 14 Kelvin. The hydrogen pressure to produce cold sources on a cold mode operation drops down to 152±3 kPa(a). Normally, the HRS should be operated before starting up the reactor. For this, the HRS should be turned on at least 12 hours before the reactor; 6 hours for removing impurities in helium, 4 hours and 20 minutes for the cold mode operation to cool down, and 1 hour and 20 minutes for stabilizing the hydrogen pressure. The helium purification should be done before the cold mode operation of the HRS. To get rid of impurities, we use a cryogenic adsorbent, activated charcoal with LH2. The gas analyzer monitors impurities such as H2O, N2, and hydrocarbon etc. The operational limit for them is below 1 ppm which is less than one tenth of the manufacturer's manual.
- Published
- 2012
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