IRSN, Institut de radioprotection et de sûreté nucléaire

Search our site :


Contact us :

En Fr

Enhancing Nuclear Safety


Theses in progress

Experimental and theoretical studies of light water effective thermal scattering kernel S(α,β)

Host laboratory: ​​Reactor Physics Research and Safety Assessment Laboratory (LNR)

Beginning of the thesis: October 2015

Student name: Vaibhav Jaiswal

Subject description

​Nuclear cross section libraries use derived thermal neutron scattering represented by

scattering kernel S(α,β) where α and β stand for the unit-less momentum and energy

transfers respectively. The available S(α,β) of light water in the evaluated data libraries

are based on physics models and experimental data measured in the sixties with a low

accuracy due to limitations of the experimental and computational capabilities. S(α,β) is

analogous to the scattering function S(q,ω) which describes the microscopic dynamics

of a scattering system, where q is the neutron momentum transfer and ω is the neutron

energy transfer. S(q,ω) for light water can be directly measured by performing time-offlight

inelastic thermal neutron scattering experiment in order to avoid approximations

and thus possibly enhance the reliability of S(α,β) and accuracy of the thermal scattering

cross section.

Improved S(q,ω) and thermal scattering cross section of light water at ambient temperature

and pressure have been successfully carried out at Institut Laue-Langevin (ILL).

The first part of my work was to extend the previous measurements beyond room temperature

and pressure, to more realistic operating conditions in connection with nuclear

power reactors. In order to accomplish this, two consecutive inelastic thermal neutron

scattering experiments was performed with light water for several high temperatures

and pressures using high resolution time-of-flight spectrometers, IN4c and IN6 at ILL

in 2015. Data reduction of the raw experimental data to obtain S(q,ω) is under process

(Figure). S(q,ω) will then be transformed into S(α,β) to calculate the double differential

thermal neutron scattering cross section. The final result will focus on the effect of

temperature and pressure on the thermal scattering kernel S(α,β) of light water and its

impact on integral experiments.


Send to a friend

The information you provide in this page are single use only and will not be saved.
* Required fields

Recipient's email:*  

Sign with your name:* 

Type your email address:*   

Add a message :

Do you want to receive a copy of this email?