The purpose of this thesis is to describe the optimisation of the cold moderator setup in the JEEP II research reactor. This includes the development of a MCNP model of the tangential beam channel of the JEEP II, combining this model with the JEEP II full core model, to consider and model the conditions within the cold moderator and calculate the effects of these conditions on the neutron flux characteristics to the outer experimental setups on the reactor. A concrete design is not proposed, but the effects of several designs of the CNS is presented and assessed. Effects of the void fraction and the ortho/para-hydrogen ratio of the liquid hydrogen in the CNS are also investigated. The performance is shown to vary greatly with the ortho/para- hydrogen ratio in the CNS. An increase in the cold neutron flux is calculated for several tested models, with an additional loss in noise in the energy spectrum.