Gamma spectrometry on fuel

aim

measurement of 1.6 MeV gamma from Ba-La in irradiated fuel rods from the VENUS critical facility

typical use

• with help of a monitor (reference source) axial and horizontal fission rate distributions in investigated VENUS fuel configurations are measured

basic mechanism

• two NaI crystals are used
• a collimator limits the measurement angle
• each NaI crystal is connected to an independent set of discriminators, from which the 1.6 MeV gamma count rate is derived
• one of the crystals is also connected to a PC spectrum card, with which a gamma spectrum is measured
• computer codes are available to analyse the measured gamma spectrum

type of samples

• VENUS or BR3 fuel rods (maximum length 1 meter)

applicability range

• accuracy: under normal conditions 1 to 2% at the 1 sigma level

turn-around time

• 1 rod per day for axial fission rate distribution
• 3 to 10 rods per day for horizontal fission rate distribution

advantages

• non-destructive method
• very accurate
• highly automated

disadvantages

• only usable with fresh fuel irradiated in zero-power facility VENUS

price indication

• on request

contact

Drs. Ir. van der Meer Klaas

aim

measurement of gamma-spectra of irradiated fuel pellets from the VENUS critical facility or other radioactive sources for a very precise fission rate distribution

typical use

• determination of fission rate distributions inside a fuel pellet (radial distribution, flux tilt) or activity distributions in other sources

basic mechanism

• gamma spectra are measured with an intrinsic Ge-detector; the measurement angle is reduced by very narrow collimators, ranging from 0.5 mm x 0.5 mm to 3 mm x 3 mm; slit collimators are also available
• very accurate positioning is possible in a two-dimensional plane and for rotation
• computer codes are available to analyse the measured gamma spectrum

type of samples

• pellets, VENUS or BR3 fuel rods, plates

applicability range

• accuracy: under normal conditions 1 to 2% at the 1 sigma level

turn-around time

• depends on the amount of measurement points; typically one or more weeks

advantages

• non-destructive method
• highly automated

disadvantages

• high activity of sample is required

price indication

• on request

contact

Drs. Ir. van der Meer Klaas

Gamma-spectrometry in hot cell laboratories (LHMA)

aim

measurement of gamma spectra of high burn-up fuel

typical use

• making gross gamma scan (axial distribution of fission products)
• determine burn-up of the fuel rod
• determine linear power of the fuel rod during last irradiation cycle
• determine fission gas release

basic mechanism

• gamma spectra are measured with an intrinsic Ge-detector; the measurement angle is reduced by slit collimators, ranging from 0.5 mm to 10 mm
• very accurate positioning is possible in axial direction
• a well-characterized reference Eu source is available
• computer codes are available to analyse the measured gamma spectrum

type of samples

• fuel rods (maximum length 4 meters)

applicability range

• accuracy: burn-up and linear power 5% at the 1 sigma level
• fission gas release 10% at the 1 sigma level

turn-around time

• one to several days per rod

advantages

• non-destructive method
• validated with reference chemical burn-up analysis
• highly automated

disadvantages

• creep of hot cell

price indication

• on request

contact

Dr. Sannen Leo