7 ms·
Kind of. When reducing power there's a buildup of a particular Xenon isotope, which is a powerful neutron adsorber. So until that isotope decays away sufficient
by jabl 6y ago
Kind of. When reducing power there's a buildup of a particular Xenon isotope, which is a powerful neutron adsorber. So until that isotope decays away sufficiently you might have problems starting the reactor back up again. Unless you have enough excess reactivity, such as by having fresher fuel loaded.
AFAIU France primarily uses reactors which are earlier in their fuel cycle for load balancing, and ones which are near the end run with a flatter profile.
- p_l 6y agoMakes sense! Didn't know about specific as it's not really my area, but would running a PWR with very high enrichment level (AFAIK some designs use 93% U-235) allow quick spin down and spin up?
- jabl 6y ago> would running a PWR with very high enrichment level (AFAIK some designs use 93% U-235) allow quick spin down and spin up? Well.. there are a lot of factors in a reactor design affecting the ability to increase or decrease power quickly. Geometry, fuel/moderator ratio, fuel density, burnable poisons (for flattening the reactivity swing over the fuel cycle), amount of control rods etc etc. Fuel enrichment being only one thing, which in turn affects other things as well (e.g. reactors using highly enriched uranium tend to use different fuel designs than low enriched fuels). But yes, military reactors for navy ships obviously have very different demands on them than civilian power reactors, and are designed accordingly. And yes, while US navy reactors use 93% enriched fuel, it's not necessary, e.g. French and apparently Chinese submarines use low enriched fuel (7% for French).