Indo - UK: Premature, Oscillation-Induced Critical Heat Flux ("Premature OICHF")
Lead Research Organisation:
Imperial College London
Department Name: Mechanical Engineering
Abstract
Water is an excellent coolant for nuclear reactors, but steam is a very poor one. The ability to predict with confidence, but without excessive conservatism, the point at which cooling by water will turn into cooling by just steam is absolutely vital. The the rate of transfer of heat at which this transition occurs is known as the "critical heat flux" (CHF).
Predicting the circumstances under which CHF would occur (and then making sure that reactor operating conditions stay well away from them) is a very large part of the thermal hydraulic design of water cooled reactors.
There are some, unusual, circumstances in which the flows inside a nuclear reactor can become unsteady and cyclical, with flow-rates rising and falling with time. Under the circumstances, predicting the critical heat flux not surprisingly becomes rather more complicated and difficult.
This project is attempting to build a computer model which will predict when critical heat flux occurs in the presence of cyclical flows. The second strand of this project is to conduct experiments in which a test section is exposed to a cyclical flow, and the occurrence or not of critical heat flux is observed. The model we develop will then be tested and refined against these measurements.
A validated, general-purpose tool for predicting critical heat flux under conditions of oscillatory flow will be a useful additional capability available to reactor designers and safety analysts.
Predicting the circumstances under which CHF would occur (and then making sure that reactor operating conditions stay well away from them) is a very large part of the thermal hydraulic design of water cooled reactors.
There are some, unusual, circumstances in which the flows inside a nuclear reactor can become unsteady and cyclical, with flow-rates rising and falling with time. Under the circumstances, predicting the critical heat flux not surprisingly becomes rather more complicated and difficult.
This project is attempting to build a computer model which will predict when critical heat flux occurs in the presence of cyclical flows. The second strand of this project is to conduct experiments in which a test section is exposed to a cyclical flow, and the occurrence or not of critical heat flux is observed. The model we develop will then be tested and refined against these measurements.
A validated, general-purpose tool for predicting critical heat flux under conditions of oscillatory flow will be a useful additional capability available to reactor designers and safety analysts.
Planned Impact
Nuclear power worldwide is a very important source of electricity, and it is a source upon which it looks probable that increased reliance will be placed in future, as concerns about the burning of fossil fuel and so on increase.
All nuclear plants need to be carefully designed to ensure that they remain properly cooled during both normal and under fault conditions. For a water-cooled plant, this means cooled by liquid water, as opposed to by steam. A better ability to predict the transition from water cooling to steam cooling will allow better design decisions to be made, and allow more reliable selection of setpoints, and thermal and power limits, and so on.
This will have significant economic benefits to the plant builder and operator, and ultimately to the consumer as it will prevent the costs of the plant being higher than they would otherwise be, and thus will similarly be reflected to it in electricity prices being less high than they might have been otherwise.
All nuclear plants need to be carefully designed to ensure that they remain properly cooled during both normal and under fault conditions. For a water-cooled plant, this means cooled by liquid water, as opposed to by steam. A better ability to predict the transition from water cooling to steam cooling will allow better design decisions to be made, and allow more reliable selection of setpoints, and thermal and power limits, and so on.
This will have significant economic benefits to the plant builder and operator, and ultimately to the consumer as it will prevent the costs of the plant being higher than they would otherwise be, and thus will similarly be reflected to it in electricity prices being less high than they might have been otherwise.
Publications
Description | This is current work in progress. It is particularly timely, as recent critical heat flux events in Switzerland seem to be directly associated with the oscillatory behaviour being addressed here. |
Exploitation Route | This is current work in progress. It is particularly timely, as recent critical heat flux events in Switzerland seem to be directly associated with the oscillatory behaviour being addressed here. |
Sectors | Energy |
Description | Collaboration with Indian DAE BARC |
Organisation | Bhabbha Atomic Research Centre |
Country | India |
Sector | Public |
PI Contribution | We are collaborating in a series of projects under the Indo-UK Civil Nuclear Programme |
Collaborator Contribution | We and BARC work together on developing measurements associated with various aspects of nuclear thermal hydraulics, and in the development and validation of models of these phenomena |
Impact | Multiple publications, multiple visits to BARC, multiple hostings of Indian scientists in the UK |
Start Year | 2015 |
Description | Indo-UK Civil Nuclear Network Conference & Meeting. 30 - 31 October 2019 Halifax Hall, Sheffield University. |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Study participants or study members |
Results and Impact | Indo-UK Civil Nuclear Network Conference & Meeting. 30 - 31 October 2019 Halifax Hall, Sheffield University. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants. |
Year(s) Of Engagement Activity | 2019 |
Description | Indo-UK Civil Nuclear Network Meeting. 03 July 2017 Mechanical Engineering Department, Imperial College London. |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Study participants or study members |
Results and Impact | ndo-UK Civil Nuclear Network Meeting. 03 July 2017 Mechanical Engineering Department, Imperial College London. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants. |
Year(s) Of Engagement Activity | 2017 |
Description | Indo-UK Civil Nuclear Network Meeting. 19 - 20 December 2016 Halifax Hall, Sheffield University. |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Study participants or study members |
Results and Impact | Indo-UK Civil Nuclear Network Meeting 19 - 20 December 2016 Halifax Hall, Sheffield University. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants. |
Year(s) Of Engagement Activity | 2016 |
Description | Indo-UK Civil Nuclear Network Meeting. 20 September 2018 The Open University, Milton Keynes. |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Study participants or study members |
Results and Impact | Indo-UK Civil Nuclear Network Meeting. 20 September 2018 The Open University, Milton Keynes. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants. |
Year(s) Of Engagement Activity | 2018 |
Description | Invited Lecture on the boiling, DNB, and its prediction, at BARC, Mumbai, February 2020 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | An invited lecture on boiling, DNB, and its prediction, to scientists from the Indian DAE laboratory BARC, and the associated HBNI University Institute |
Year(s) Of Engagement Activity | 2020 |
Description | Invited lecture to Westinghouse (Sweden) Meeting og BWR fuel users |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | I was invited to give a lecture on BWR fuel Critical Heat Flux prediction methods |
Year(s) Of Engagement Activity | 2017 |
Description | Online resources: official website of the Indo-UK Civil Nuclear Network, https://indouk-civilnuclear.org |
Form Of Engagement Activity | A magazine, newsletter or online publication |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Generation of online resources available to everyone is interested at https://indouk-civilnuclear.org. Information on current and previous Indo-UK grants; publications; events; past and upcoming workshops and meetings. |
Year(s) Of Engagement Activity | 2018,2019,2020 |
URL | https://indouk-civilnuclear.org |