December, 2012

Sizewell Nuclear Waste Dump

Unlike Sizewell A the waste from Sizewell B and from the proposed Sizewell C&D are to be stored on site until at least 21301. This will turn the Sizewell area into a massive nuclear waste dump for at least the next 110 years. The site will contain over 100 times the amount of radioactivity released […]

Share

Posted in Spent Fuel | No Comments »

Cs-137 Inventories in Spent Fuel

In my previous post I showed a method of getting a rough idea about how much Cs-137 there is in spent fuel as it leaves the reactor. Once it leaves the reactor the Cs-137 decays with a half-life of about 30 years. Therefore the amount of Cs-137in the spent fuel removed on the first year […]

Share

Posted in Spent Fuel | 2 Comments »

Cs-137 in Spent Fuel as it leaves the reactor

I am now going to get a rough idea of how much caesium 137 there is in spent nuclear fuel. One reason for choosing Cs-137 is that it is a major fission product, it has a reasonably long half-life (30.17 years), it has a low melting and boiling point and is readily absorbed by the […]

Share

Posted in More Advanced, Spent Fuel | No Comments »

Production and Decay of Fission Products

We are going to assume that the fissile product has one mode of decay and does not do anything naughty such as undergo neutron capture. We can then write its rate of production as: where is the decay constant for fission product N, is the number of fissions per second and is the fraction of […]

Share

Posted in More Advanced, Spent Fuel | No Comments »

Composition of Spent Fuel

The fuel in modern nuclear power plants is enriched to 3-5% U-235 (which is the isotope that undergoes fission). Therefore we might expect that spent fuel contains roughly 3-5% fission products. It is a bit more complicated than this which I will go into in this blog. Despite the small percentage of fission products in […]

Share

Posted in Spent Fuel | No Comments »

Radioactivity of U-238

This is just an example of how to calculate the radioactivity of an isotope from its halflife. Uranium 238 has a halflife of 4.468×109 years (4,468,000,000years). This is 4.468×109 x 365.25 x 24 x 60 x 60 = 1.41×1017 seconds. We can now calculate the decay constant (i.e. the number of decays per second) using […]

Share

Posted in Basic | No Comments »

A Rough Model of a Nuclear Reactor

This model is very rough however it gives some idea  about power and energy output from a nuclear reactor which I will use in later posts. The model is very simplistic but is useful in understanding some of the processes that are going on. We are going to assume that all the power is from […]

Share

Posted in More Advanced | No Comments »

Implications of High Burnup Fuel – Basic Notes

An important issue around nuclear new build is the amount and what happens to the spent fuel. The proposed EPR reactors at Sizewell and Hinkley are designed to run oh ‘high burnup’ fuel. This post has a basic look at what the implications are. This is a rough wordy explanation and I hope to be […]

Share

Posted in Basic, Spent Fuel | No Comments »

Spent Fuel – Basic Notes

These are just a few basic notes about spent fuel waste from nuclear power stations. It assumes a basic understanding of the nuclear fission process (see Basic Nuclear Physics workshop), however, I have tried to provide links to the relevant sections within this blog. This post is designed as a basic introduction for the discussion […]

Share

Posted in Basic, Spent Fuel | No Comments »

Uranium Enrichment Formula

This is another one of those background information posts deriving the mass balances for uranium enrichment. Let us consider the following enrichment  scenario: We have mass F of unenriched uranium entering on the left. It has Nf of U-235 (0.72% for natural uranium). After enrichment mass P of product enriched to Np of U-235 and […]

Share

Posted in More Advanced, Spent Fuel | 1 Comment »

Subscribe