Three advantages of building very small reactors: 1) Because heat output scales with the cube of the size and passive thermal dissipation scales with the squar

Three advantages of building very small reactors: 1) Because heat output scales with the cube of the size and passive thermal dissipation scales with the square, small units can be more easily designed to stay within thermal bounds when active cooling fails. 2) One of the biggest cost for nuclear construction is interest costs during the construction process, reducing that time makes a big difference. 3) When you build 20 small units you get 20 chances to make small enhancements and 20 chances to get better and faster at building them. When you build one large unit (which is almost definitely more cost effective on paper) you get one chance to do it and it takes so long that even if you build more than one of the same design, you'll never have the same team building multiple units.