Modeling Passive Fast-Neutron Emission Tomography of Spent Nuclear Fuel

Conference · Tue May 01 00:00:00 EDT 2018

OSTI ID:1545240

Hausladen, Paul  ^[1]; Iyengar, Anagha ^[1]; Fabris, Lorenzo  ^[1]; Yang, Jinan  ^[1]; Hu, Jianwei  ^[1]; Lousteau, Angela L.  ^[1]

---

1. ORNL

For the past year Oak Ridge National Laboratory has been developing a passive fast-neutron emission tomography capability. Like the passive gamma emission tomography capability presently being evaluated by the International Atomic Energy Agency, the goal of this capability is to detect the removal or substitution of individual fuel pins in spent nuclear fuel assemblies for international safeguards applications, such as verifying the integrity of an assembly before transfer to difficult-to-access storage. The present imaging technique is based on neutron emissions originating primarily from curium-244, which is produced predominantly at the end of the exposure cycle. As a result, this technique may be sensitive not only to fuel pins that are removed or substituted subsequent to all irradiation, but also to fuel pins that are substituted and subsequently irradiated. At present, a laboratory prototype imager is under construction. The purpose of the prototype is to demonstrate an imaging capability sufficient to resolve individual fuel pins using commercially available boron straw detectors that can withstand the high gamma ray dose from a typical spent fuel assembly. To achieve both practical measurement durations and sufficient resolution to discern individual pins, the prototype imager employs a novel collimator design where the slits of a parallel-slit collimator are rearranged to distribute them around a ring surrounding the target fuel assembly. This presentation will report on simulations to understand the neutron signal-to-noise ratio and gamma dose rate as a function of the collimator design, the neutron detector’s response to gamma rays as a function of dose rate, and image reconstruction challenges associated with this collimator design.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1545240
• Resource Relation: Conference: International Workshop on Numerical Modeling of NDA Instrumentation and Methods for Nuclear Safeguards - Luxemburg City, , Luxembourg - 5/16/2018 12:00:00 PM-5/17/2018 12:00:00 PM
• Country of Publication: United States
• Language: English