Whilst trying to write an electronic question using a popular open source application. I compiled a comprehensive list of fission products sourced from Wikipedia. Now a "textbook example of fission" is something like

$$ \rm ^{235}U + n \to {}^{92}Kr + {}^{141}Ba + 3n $$

However, the heaviest fission product listed by Wikipedia is Kr-86. In fact, taking the heaviest isotopes from random nuclides in the list and ensuring the proton content for both sums to 92, the neutron yield is far in excess of the average yield (between 2 and 3) For a fission reaction. Or are the listed isotopes are not simply heavy enough?

So pardon the pun, something is not adding up. Is the textbook example naive in that it uses an isotope of Kr not seen in nuclear fission or are the listings of fission product in Wikipedia's isotope list incomplete. If the latter is true can anyone suggest a more reliable source for information on fission products.

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    $\begingroup$ Perhaps it only lists significant fission products. Krypton-92 has a half-life of less than 2 seconds, so it's not in the fission product mixture by the time you take it out of the reactor. Within a day or so, krypton-92 has decayed several times to reach zirconium-92, which is listed. $\endgroup$ – Chris Nov 30 '17 at 9:55

The introduction to the Nuclear Wallet Cards, a reference product maintained by the National Nuclear Data Center, says

The $^{235}\rm U$ thermal fission products, with fractional cumulative yields $≥ 10^{-6}$, are italicized in the table. The information on fission products is taken from the ENDF/B-VI fission products file [9].

You can see below that the krypton fission fragments include mass numbers 84--98 (but not 97).

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