Spent Fuel Measurements and Analysis for International Nuclear Safeguards

March, 2017

Paul De-Baere, a Euratom inspector, and Jianwei Hu from ORNL (right) jointly conducted two FDET spent fuel measurement campaigns in 2014 and 2015 at the Central Interim Storage Facility for Spent Nuclear Fuel (Clab) facility in Sweden. 

Increases in spent fuel assembly transfers to intermediate dry storage facilities and plans to operate permanent geological repositories in the next decade have increased the demands on international safeguards inspections for more efficient and effective measurements to verify declarations and for improved partial defect (e.g., missing fuel rods) detection in spent nuclear fuel. Development of advanced measurement technologies and data analysis software can be used by safeguards authorities to strengthen spent fuel safeguards.

Technical Approach

The Fork detector (FDET), equipped with both neutron and gamma detectors, is one of the primary instruments used for spent fuel safeguards measurements. Oak Ridge National Laboratory (ORNL) has developed an FDET data analysis module using the ORIGEN burnup code with MCNP-generated detector response functions for automated and efficient data analysis for use by inspectors for underwater measurements. Measurements of spent fuel rods with FDET instruments are planned to be performed at the ORNL hot cell facility. The measurement data will be used to validate the extension of ORIGEN in the FDET data analysis module to in-air measurements, which are required at the planned spent fuel encapsulation plant in Finland. The measurements will also be used to quantify the performance of several alternative detector components for the FDET in both unmoderated and moderated environments.

Discussing spent fuel measurement plans at ORNL hot cell facility.  (hi-res image)


Measurement data analysis software significantly enhances the capability and efficiency to safeguard spent fuel by automating data analysis for the inspector and verifying declarations using predicted FDET count rates in real time. Experimental data to be collected in the hot cell will be valuable to confirm the performance of the standard FDET, the alternative detector components, and the software for in-air measurements, which will be similar to those to be performed at the Finnish spent fuel encapsulation plant.

A spent fuel assembly being measured using an FDET.  (hi-res image)


DOE/NNSA, Office of Nonproliferation and Arms Control

International Nuclear Safeguards Engagement Program

Safeguards Technology Development Program


European Atomic Energy Community (Euratom)

Los Alamos National Laboratory

Principal Investigators

Ian C Gauld  

Jianwei Hu

The ORIGEN module for predicting FDET count rates in real time of a given spent fuel assembly based on operator declarations.  (hi-res image)