広島・長崎原爆による放出エネルギーの配分に関するノート

The energy distribution released by the Hiroshima-Nagasaki type atomic bomb explosion is usually illustrated using a circle graph consisting of 50 % blast/shock, 35 % heat radiation, 5 % initial radiation and 10 % residual radiation. The origin of this circle graph is found to be in a series of enlightenment books describing the effects of atomic/nuclear weapons edited by Samuel Glasstone and sponsored by the US government. In this note, through detailed checking the contents of four Glasstone books: 1950, 1957, 1962 and 1977 versions, several misinterpretations and inappropriate translations found in Japanese books are explained. The term of “residual nuclear radiation” that means late radiations emitted after the explosion is misunderstood in Japanese books as “residual radiation” that means radiation from local fallout and neutron induced radioactivity near the hypocenter. Because the 10 % fraction for “residual (or delayed) nuclear radiation” is not included in the explosion energy when it is expressed as TNT equivalent value of kiloton, the circle graph illustrating the energy distribution from atomic bomb becomes a cause of misunderstanding.