Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Using antineutrinos to monitor nuclear reactors

24.04.2014

Astroparticle physics methodology applied to nuclear facility monitoring

When monitoring nuclear reactors, the International Atomic Energy Agency (IAEA) has to rely on input given by the operators. In the future, antineutrino detectors may provide an additional option for monitoring. However, heretofore the cumulative antineutrino spectrum of uranium 238 fission products was missing. Physicists at Technische Universität München (TUM) have now closed this gap using fast neutrons from the Heinz Maier Leibnitz Neutron Research Facility (FRM II).


Dr. Nils Haag developed an experimental setup that allowed him to determine the missing spectrum of uranium 238. (Bild: Wenzel Schuermann / TU München)

In addition to neutrons, the fission reaction of nuclear fuels like plutonium or uranium releases antineutrinos. These are also electrically neutral, but can pass matter very easily, which is why they can be discerned only in huge detectors. Recently, however, detectors on the scale of only one cubic meter have been developed. They can measure antineutrinos from a reactor core, which has generated great interest at the IAEA.

Prototypes of these detectors already exist and collect data at distances of around 10 meters from a reactor core. Changes in the composition of nuclear fuels in the reactor – for example, when weapons-grade U-239 is removed – can be determined by analyzing the energy and rate of antineutrinos. This would free the IAEA from having to rely on representations of reactor operators.

Antineutrino spectrum of uranium 238 revealed

In the 1980s the antineutrino spectra of three main fuel isotopes, uranium 235, plutonium 239 and plutonium 241, were determined. However, the antineutrino spectrum of the fourth main nuclear fuel, uranium 238, which accounts for approximately 10 percent of the total antineutrino flux, remained unclear. It had only been estimated using inaccurate theoretical calculations and thus limited the accuracy of the antineutrino predictions.

Dr. Nils Haag from the Chair of Experimental Astroparticle Physics at TU München recently developed an experimental setup at the FRM II that allowed him to determine the missing spectrum of uranium 238. "I needed a high flux of fast neutrons to induce the fission of the U-238," says the physicist. This is why he located his experimental setup at the NECTAR radiography and tomography station of the FRM II – a source of fast neutrons.

Second detector for background-free measurement

The neutrons induce nuclear fission in a film of U-238. The radioactive decay products then emit electrons and antineutrinos. The electrons were investigated using a scintillator – a block of plastics that converts the kinetic energy of the electrons into light. A photomultiplier then translates this into electrical signals.

The nuclear decay also generates gamma radiation that produces unwanted events in the scintillator. Therefore, Haag placed a second detector right in front of the scintillator: a so-called multi-wire proportional chamber. Since only charged particles like electrons trigger a signal in the gas detector, the researcher was able to determine and subtract the proportion of gamma radiation. Haag then inferred the antineutrino spectrum using this background-free measurement data.

Method allows better monitoring of reactor cores

The measurement of the antineutrino spectrum can be used to monitor the status, performance and even composition of reactor cores. "Our results open the door to predict with significantly higher accuracy the expected antineutrino spectrum emitted by a reactor running on a fuel composition reported by the operator," explains Dr. Nils Haag. "Deviations of antineutrino detector measurement data from expected reactor signals can thus be exposed."

The development of this methodology is embedded in basic research on the phenomenon of so-called "sterile" antineutrinos. Comparing previously made measurements and predictions of reactor antineutrino spectra gave rise to the assumption that some of the antineutrinos turned "sterile" after being produced. They were then no longer able to react with other matter. A better understanding of this effect would expand our knowledge of elementary physical processes.

This research was funded by the German Research Foundation (DFG) and the DFG Excellence Cluster "Origin and Structure of the Universe" at TUM.

Publication:

Experimental Determination of the Antineutrino Spectrum of the Fission Products of U238, N. Haag, A. Gütlein, M. Hofmann, L. Oberauer, W. Potzel, K. Schreckenbach, and F. M. Wagner, Phys. Rev. Lett. 112, 122501 (2014), DOI: 10.1103/PhysRevLett.112.122501, 
journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.122501

Contact

Dr. Nils Haag
Technische Universität München
Chair for Experimental Physics and Astroparticle Physics
Tel.: +49 89 289 12524, E-mail - Internet

Nils Haag | Eurek Alert!

Further reports about: Antineutrino Astroparticle FRM IAEA TUM antineutrinos detector determine energy experimental measurement reactor

More articles from Physics and Astronomy:

nachricht Merging galaxies break radio silence
28.05.2015 | ESA/Hubble Information Centre

nachricht New Technique Speeds NanoMRI Imaging
28.05.2015 | American Institute of Physics (AIP)

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Solid-state photonics goes extreme ultraviolet

Using ultrashort laser pulses, scientists in Max Planck Institute of Quantum Optics have demonstrated the emission of extreme ultraviolet radiation from thin dielectric films and have investigated the underlying mechanisms.

In 1961, only shortly after the invention of the first laser, scientists exposed silicon dioxide crystals (also known as quartz) to an intense ruby laser to...

Im Focus: Advance in regenerative medicine

The only professorship in Germany to date, one master's programme, one laboratory with worldwide unique equipment and the corresponding research results: The University of Würzburg is leading in the field of biofabrication.

Paul Dalton is presently the only professor of biofabrication in Germany. About a year ago, the Australian researcher relocated to the Würzburg department for...

Im Focus: Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...

Im Focus: IoT-based Advanced Automobile Parking Navigation System

Development and implementation of an advanced automobile parking navigation platform for parking services

To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...

Im Focus: First electrical car ferry in the world in operation in Norway now

  • Siemens delivers electric propulsion system and charging stations with lithium-ion batteries charged from hydro power
  • Ferry only uses 150 kilowatt hours (kWh) per route and reduces cost of fuel by 60 percent
  • Milestone on the road to operating emission-free ferries

The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International symposium: trends in spatial analysis and modelling for a more sustainable land use

20.05.2015 | Event News

15th conference of the International Association of Colloid and Interface Scientists

18.05.2015 | Event News

EHFG 2015: Securing health in Europe. Balancing priorities, sharing responsibilities

12.05.2015 | Event News

 
Latest News

Siemens will provide the first H-class power plant technology in Mexico

28.05.2015 | Press release

Merging galaxies break radio silence

28.05.2015 | Physics and Astronomy

A New Kind of Wood Chip: Collaboration Could Yield Biodegradable Computer Chips

28.05.2015 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>