Featured Research

from universities, journals, and other organizations

Using antineutrinos to monitor nuclear reactors

Date:
April 24, 2014
Source:
Technische Universitaet Muenchen
Summary:
When monitoring nuclear reactors, the International Atomic Energy Agency 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 have now closed this gap using fast neutrons.

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

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).

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.


Story Source:

The above story is based on materials provided by Technische Universitaet Muenchen. Note: Materials may be edited for content and length.


Cite This Page:

Technische Universitaet Muenchen. "Using antineutrinos to monitor nuclear reactors." ScienceDaily. ScienceDaily, 24 April 2014. <www.sciencedaily.com/releases/2014/04/140424102831.htm>.
Technische Universitaet Muenchen. (2014, April 24). Using antineutrinos to monitor nuclear reactors. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2014/04/140424102831.htm
Technische Universitaet Muenchen. "Using antineutrinos to monitor nuclear reactors." ScienceDaily. www.sciencedaily.com/releases/2014/04/140424102831.htm (accessed October 20, 2014).

Share This



More Matter & Energy News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Robotic Eyes' Helps Japan's Bipedal Bot Run Faster

'Robotic Eyes' Helps Japan's Bipedal Bot Run Faster

Reuters - Innovations Video Online (Oct. 16, 2014) — Japanese researcher uses an eye-sensor camera to enable a bipedal robot to balance itself, while running on a treadmill. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Lockheed Martin's Fusion Concept Basically An Advertisement

Lockheed Martin's Fusion Concept Basically An Advertisement

Newsy (Oct. 15, 2014) — Lockheed Martin announced plans to develop the first-ever compact nuclear fusion reactor. But some experts said the excitement is a little premature. Video provided by Newsy
Powered by NewsLook.com
First Confirmed Case Of Google Glass Addiction

First Confirmed Case Of Google Glass Addiction

Buzz60 (Oct. 15, 2014) — A Google Glass user was treated for Internet Addiction Disorder caused from overuse of the device. Morgan Manousos (@MorganManousos) has the details on how many hours he spent wearing the glasses, and what his symptoms were. Video provided by Buzz60
Powered by NewsLook.com
Science Proves Why Pizza Is So Delicious

Science Proves Why Pizza Is So Delicious

Buzz60 (Oct. 15, 2014) — The American Chemical Society’s latest video about chemistry in every day life breaks down pizza, and explains exactly why it's so delicious. Gillian Pensavalle (@GillianWithaG) has the video. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins