The Mudcat Café TM
Thread #136314   Message #3112413
Posted By: josepp
12-Mar-11 - 12:07 PM
Thread Name: BS: Japan Nuclear plant disaster, 2011
Subject: RE: BS: Nuclear plant disaster looming
////Of the dizens if nuclear plants in Japan, currently the oldest one bulit in 1960 and finished in 1970 is in the most serious condition of being unable to cool the fuel rods which are now venting radiactive steam.////

Maybe plant designs have changed since I worked in them, but I never heard of fuel rods and they can't vent steam. The fuel comes in very thin plates and "very pure water", called a moderator, is pumped around them. The rods are made usually of hafnium and actually absorb neutrons which has the effect of squelching fission reactions. A total insertion of all the rods at once is called a scram and that shuts the reactor down. Now I do know of plants that actually used water in place of the rods and it is possible those might flash to steam but they are not fuel either.