It has been stated that the sampling system should be able to do the following things. A) Fill and empty the reactor. B) Bring out samples of the soup. C) Measure the soup level. The basic components of a system capable of doing these things are: 1) Sampling tubes. 2) Sampling funnels with traps. 3) Air filter. 4) Preasure-vac/uum system with manometers.

Arrangement. 2 and 3 will be hot from gaseous fission products, and should therefore be located in the concrete box on top of the reactor shield. As 4 must be directly accessible for the reading of the manometers, it has to be put outside the reactor. Note, however, that C) cannot be performed if the airfilter has this position between the manometer and the reactor.

Materials and some details. 1 and 2 should be made of stainless steel and electric level indicators provided. The arrangement of the insulators for these indicators seems to be a major problem because of the space they need.

A satisfactory airfilter has to be found.

The requirements on the valves that are to handle the soup are as follows. They must be fastclosing stainless steel valves without gaskets and without spaces from which the soup cannot be easily washed away. If suitable valves cannot be found, I suggest that a valveless system be developed. Figure 1 shows one principle for such an arrangement. Filling : D open. Suck gently on E. When the level reaches F, cut off the pump and let air in slowly through E. Emptying : D closed. Apply a low pressure on E. Note that all tubes between G and the trap must be short and wide to prevent pressure gradients.