Em. Attas et al., A NUCLEAR-FUEL VERIFICATION SYSTEM USING DIGITAL IMAGING OF CHERENKOVLIGHT, Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment, 384(2-3), 1997, pp. 522-530
An UV-sensitive scientific CCD camera has been tested at a power react
or facility to image the faint Cherenkov light from irradiated nuclear
fuel. The instrument mates custom optical components (lens, UV-pass f
ilter) to a commercial scientific camera (Astrocam 4100) with a coated
frame-transfer CCD chip (EEV 37-10) to produce 12-bit images of 512 x
512 pixels at several frames per second, A 250-mm f/2.6 catadioptric
lens has been designed with transmissive optics optimized for this app
lication, incorporating colour correction for viewing through 10 m of
water, The filter has an average transmission of 80% from 280 to 320 n
m, with visible-light transmission of less than 0.03% from 365 to 780
nm to block artificial lighting in the fuel bay. Measurements were mad
e with this instrument at the Ringhals Nuclear Power Plant, and the CL
AB fuel storage facility in Sweden. Both fuel and non-fuel assemblies
of boiling-water reactor (BWR) type were studied. Performance is super
ior to that of the earlier Cherenkov viewing devices (CVDs) based on i
mage intensifier tubes. Increased sensitivity extends the range of the
Cherenkov verification technique to fuel with older discharge dates.
Increased resolution allows fine details of the fuel to be examined fo
r higher-confidence safeguards verification. Sample digital images are
presented, and the advantages to irradiated-fuel verification of imag
e quantitation, storage, transmission, and processing are discussed.