Ringhals Diagnostics and Monitoring, Annual Research Report 2016-17
Rapport, 2017

This report gives an account of the work performed by the Division of Subatomic and Plasma Physics (formerly, Division of Nuclear Engineering), Chalmers, in the frame of a research collaboration with Ringhals, Vattenfall AB, contract No. 663628-054. The contract constitutes a 1-year co-operative research work concerning diagnostics and monitoring of the BWR and PWR units. The work in the contract has been performed between July 1st 2016, and December 31st, 2017. During this period, we have worked with six main items as follows:

1. Further development and improvement of the coupled coarse-fine mesh CORE SIM-based model;

2. Further investigation of the point-kinetic component of the noise induced by fuel assembly vibrations;

3. Analysis of new ex-core measurements, taken in R-4 after power increase;

4. Further development and test of the mode separation model as applied to 3-D “wobbling” type or “tilting” type core-barrel vibrations;

5. A basic study in neutron noise theory which could provide some indirect support for the determination of the void fraction from neutron noise measurements;

6. A pilot study of the possibility of using fission chambers for zero power noise experiments.

The work was performed at the Nuclear Engineering Group of the Division of Subatomic and Plasma Physics, Chalmers University of Technology by Imre Pázsit (project co-ordinator), Cristina
Montalvo (visitor from the Technical University of Madrid), Hoai-Nam Tran (research collaborator from Duy Tan University, Vietnam), Omar Alejandro Olvera Guerrero (visitor, PhD student at UAM/Autonomus Metropolitan University, Mexico City, Mexico) and Henrik Nylén, the contact person at Ringhals. The measurements reported in Chapter 6 were designed and executed by our collaborating partners in EPFL/PSI, Mathieu Hursin, Oskari Pakari and Vincent Lamirand.

core-barrel motion

Reactor diagnostics


Noise analsys



Imre Pazsit

Chalmers, Fysik, Subatomär fysik och plasmafysik

Cristina Montalvo

Universidad Politecnica de Madrid

Hoai Nam Tran

Unknown organization

Henrik Nylén

Ringhals AB

Omar Alejandro Olvera Guerrero

Unknown organization


Övrig annan teknik

Annan fysik




Chalmers tekniska högskola