Japan reator restratsCertainly this is very important as there are about 40 to come back on line, but some of the ones shutdown may be retired as they are too old to do the costly upgrades.
Currently 43 reactors are operable and potentially able to restart, and 24 of these are in the process of restart approvals.
Japan needs to import about 84% of its energy requirements, which is quite costly since these are fossil fuels. So economically there is a large incentive to get these back on line.
THere were fuel (uranium) supply contracts in place when they were all shut down, so there is an inventory of uranium to work thru. THis will get shuffled around a bit to minimize costs, but as the reactors come back on line, they will beging to look at long term suypply contracts again.
Most of the modifications required were to simply put their standby generators up on a hill (higher ground) so a psunami could not flood them, and to make the standby power systems much more reliable, and also to put in flood protection barriers.
In some cases there will have been some structural beefing up with things like shock absorbers to support equipment.
Except for the flooded reactors, there were no failures of components at any of the other reactors, so they rode out the shaking very well, but most were far enough away so there was no impact at all from shaking.
In a global sense the Japan event was helpful to make all reactor operators realize the importance of safety systems and many have upgraded these safety systems. THis is good for the long term.
THe first reactor start will provide somewhat of a psychological boost to nuclear power and the Japanese are very wise to make sure all goes well with the first one, well all of them really as there are a bunch.
Starting up reactors that have been shutdwon for some time has to be done very carefully to bring the power levels up very gradually so they are on scale. As the power is raised up thry 1% all the systems, pumps, shutdown systems, control systems have to go thru various stages of checking all is well.
Most likely they will have loaded in a full load of fuel too during the shutdown, so once running they won't have to be shutdown to be refuelled for some time. Making sure they have a fresh load of fuel will have used up some of the new fuel inventory.
If all goes well, and no reason to expect not, there might be several reactors running by the end of 2015.