Since 18 of December 2019 conferences.iaea.org uses Nucleus credentials. Visit our help pages for information on how to Register and Sign-in using Nucleus.
Apr 19 – 22, 2022
Vienna, Austria
Europe/Vienna timezone
FR22 starts in Vienna 19 - 22 April 2022 Online Stream: https://event.do/iaea/a/#/events/5048

On substantial slowing down of the kinetics of fast transient processes in fast reactor

Apr 19, 2022, 1:00 PM
2h
Vienna, Austria

Vienna, Austria

POSTER Track 1. Innovative Fast Reactor Designs Poster Session

Speaker

Dr Evgeny Kulikov (National Research Nuclear University MEPhI)

Description

The neutron lifetime is an important parameter of the reactor kinetics. When the inserted reactivity is more than the effective fraction of delayed neutrons, the reactor kinetics becomes very rapid. The fast reactor kinetics can be slowed down by increasing the neutron lifetime. The possibility of using lead isotope 208Pb as a neutron reflector with specific properties in the lead-cooled fast reactor is considered. A point kinetics model has been chosen to assess the emerging effects. The model takes into account the effects produced by neutrons returning from 208Pb-reflector to the reactor core.
Such specific properties of 208Pb as large atomic weight, weak neutron absorption allow neutrons from the reactor core to penetrate deeply into 208Pb-reflector, slow down there and have a noticeable probability to return to the reactor core and affect the chain fission reaction. The neutrons coming back from 208Pb-reflector have a long “dead-time” which represents the sum of times when neutrons leave the reactor core entering 208Pb-reflector and then diffuse back into the reactor core. During the “dead-time” these neutrons can’t affect the chain fission reaction. The neutrons returning from deep layers of 208Pb-reflector are close to the delayed neutrons in the terms of time delay. Moreover, the number of the neutrons coming back from 208Pb-reflector considerably exceeds the number of the delayed neutrons.
As a result, the neutron lifetime formed by the prompt neutron lifetime and the “dead-time” of the neutrons from 208Pb-reflector can be substantially increased. This can lead to the longer reactor period, which mitigates the effects of prompt super-criticality. To conclude, the use of lead isotope 208Pb as a neutron reflector can improve significantly safety of the fast reactor operation.

Speaker's title Mr
Country/Int. organization Russian Federation
Speaker's email address egkulikov@mephi.ru
Affiliation/Organization National Research Nuclear University MEPhI

Primary authors

Dr Gennady Kulikov (National Research Nuclear University MEPhI) Prof. Anatoly Shmelev (National Research Nuclear University MEPhI) Dr Vladimir Apse (National Research Nuclear University MEPhI) Dr Evgeny Kulikov (National Research Nuclear University MEPhI)

Presentation materials

There are no materials yet.

Peer reviewing

Paper