# Nuclear disaster

Nuclear disaster is a human-caused catastrophe, characterised in that, that the significant (and dangerous) amount of unstable isotopes is released into atmosphere, water, ground.

The most known nuclear disasters are the

Application of a nuclear weapon or its testing also can be considered as a nuclear disaster.

## Chernobyl disaster

At the Chernobyl disaster, estimates of amount of the most important contaminants released are suggested by Aleksandr Borovoi [1]:

$\begin{array}{ccccrrt} \rm Isotope & \rm mode & T_{1/2},~\rm y & \rm mass,\, kg & \rm activity,\, Ci \!\!\!\! \\ \rm ^{238}Pu & \alpha & 86 & ~1.5\!\!\!\!\! & 2.5\!\times\! 10^4 \\ \rm ^{239}Pu & \alpha & 2.4\!\times\! 10^4&\!\!420 & 2.6\!\times\! 10^4 \\ \rm ^{240}Pu & \alpha & 6.5\!\times\! 10^3&\!\!175 & 4\!\times\! 10^4\\ \rm ^{241}Pu & \beta & 14 &50 & 5\!\times\! 10^5\\ \rm ^{137}Cs &\beta,\gamma& 30 &81 & 7\!\times\! 10^6\\ \rm ^{90}Sr &\beta & 29 &43 & 6\!\times\! 10^6\\ \end{array}$

The most important contaminants seems to be Pu-238, Pu-239, Pu-240, Pu-241 (that in, roughly, 14 years gradually converts to the even more dangerous Am-237), Cs-137 (that emits not only $\beta$ rays, but $\gamma$ rays too), Sr-90 (that chemically behaves as Calcium and tends to accumulate in bones)

The short–living isotopes of Iodine are dangerous only within first weeks since the disaster; as for Radon, it does not accumulate in a human bogy.

Also, usually, one does( not consider as serious contaminant isotopes of Uranium: U-232 (due to its low concentration in the pollution), U-233, U-235, U-239 due to their long halftime (longer than $10^5$ years).

However, the concentration of U-232 is expected to be high at the destruction of equipment that uses thorium as fuel (through the U-233).

## References

1. http://scepsis.net/library/id_711.html Александр Боровой. Внутри и вне Саркофага. «Природа», №11, 1990 год.

## Keywords

1957.09.29.Mayak disaster [[]], Chernobyl disaster, Fukushima disaster, Nuclear disaster, [[]],,,,,