Problem Statement:

The ML-1 reactor (mobile low power reactor 1) was a Brayton cycle nitrogen-cooled, water-moderated reactor designed by Aerojet-General Corporation. This was part of the United States Army Nuclear Power Plant Program (USANPP) and like many reactors in this program; it had a power rating less than 2 MWe. This reactor plant was transported on standard army trailers. The purpose of the ML-1 power plant was to provide electrical power to remote locations. It was intended to provide power to run a field hospital. The ML-1 reactor was during the years of 1961-1964. By 1965, all power plants of the USANPP had been phased out. Figure 1 shows a schematic of the ML-1 plant system. In Tables 1-4 show some relevant data pertaining to the ML-1 design.

Figure 1. Schematic of ML-1 plant system

Table 1. General information on temperatures, pressures, etc

Table 4. Pre-cooler details

Question 1:

Calculate the thermal efficiency of the ML-1 nuclear plant using the information provided in Table 1-4. Please note that you may not need to use all the information provided. Figure 2 shows a simplified version of Figure 1. Figure 3 shows a T-S diagram that corresponds with Figure 2. Please show all work.

Figure 2. Simplified diagram of ML-1 plant system

Figure 3. Temperature-entropy (T-S) diagram of ML-1 plant system

Question 2:

In Figure 4, a 2^nd recuperator (R2) of the same model has been added. Flow control valves have been added to divide the flow going to R1 and R2 from the turbine and the compressor. Find values of the mass flow rates such that the thermal efficiency is greater than that of Question 1.

Figure 4. ML-1 plant system with an additional recuperator