Nuclear fuel - Wikipedia, the free encyclopedia

In boiling water reactors (BWR), the fuel is similar to PWR fuel except that the bundles are "canned"; that is, there is a thin tube surrounding each bundle. This is primarily done to prevent local density variations from affecting neutronics and thermal hydraulics of the reactor core. In modern BWR fuel bundles, there are either 91, 92, or 96 fuel rods per assembly depending on the manufacturer. A range between 368 assemblies for the smallest and 800 assemblies for the largest U.S. BWR forms the reactor core. Each BWR fuel rod is back filled with helium to a pressure of about three atmospheres (300 kPa).

So at a minimum there are 91 x 368 fuel rods per core, or no less than 33,500 rods per core.

For PWRs, the figures are similar so the 368 assemblies is not a typo of the kind that 4 assemblies of 92 adds up to 368 bundles.

There are about 179-264 fuel rods per fuel bundle and about 121 to 193 fuel bundles are loaded into a reactor core. Generally, the fuel bundles consist of fuel rods bundled 14x14 to 17x17.

That's at least 21,500 rods in a PWR.

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11