The 107-B retention basin was constructed in 1943--44 as part of the original reactor installation. Thermal stressing has caused extensive cracking of the concrete walls and leaking at cracks and joints, requiring repeated maintenance including a major repair program in 1952--53. Although a major repair or replacement program will eventually be necessary, existing basin leakage does not require immediate action, other than periodic control effort, with one exception. Effluent from 107-B leakage is flowing into the 181-B river pumphouse forebay, measurably increasing the temperature of the raw water and raising the question of continued stability of the building foundation. A basic inadequacy also exists in the inability to dispose of undesirable effluents other than to the river. The unique situation of B Reactor adjacent to the C Reactor effluent system permits consideration of improving the effluent disposal situation in this one area with minimum capital investment. The purpose of this report is to provide the scope for a project proposal for interim effluent system modifications in 100-B Area only. This will avoid future production losses and improve effluent disposal capability during resolution of a more permanent solution to the overall problem of effluent routing and treatment.