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rH = 3.5 ft, bH = 0.5 ft, NH(0) = 1.0 × i0'7/cc, NH(rH) =

4.0 x 1019/cc.  For T(0) = 40,0000K, rH = 3.0 ft, b H

0.6-5 ft, N H (0) = 1.0 x 107/cc, NH(r ) = 5.0 x 10lg/cc. For T(0) = 50,000°K and 60,000°K, r = 3.5 ft, b = 0.75 ft, H                                              H
NH(0) = 2.0 X 1017/cc, NH(rH) = 5.5 x 1019/cc.  For T(0) = 70,000°K and 80,000°K, rH = 3.25 ft, b = 1.05 ft, N (0) = HH                                                 H
2.5 x 1017/cc, NH(rH) = 6.0 x 10'9/cc.

        The temperature distributions in Figure 21 are used to solve for the pressure required to maintain the reactor critical. These resulting pressure-temperature trajectories along which the reactor is critical are shown in Figure 22. These curves show the average coolant and core temperatures which can be attained for a given critical pressure. For example, at a pressure of 300 atmospheres, the critical reactor has average coolant and core temperatures of 17,500*K and 27,0000K, respectively. It is seen that pressures in excess of 1000 atmospheres will be required to achieve average coolant temperatures greater than 60,000°K. The indicated deviations on the pressure-temperature curves account for the non-uniqueness of the seed ratio and density distributions used in equation (8.49). As indicated previously, the temperature distributions are determined by five groups of parameters. Unique seed ratios and density distributions must be