The Real-Time Detection Methods to Monitor TRU Composition in
the UREX + Process Stream project is a large project consisting of
three students and two professors from Texas A & M University
and groups at Purdue University, University of Illinois, and
Argonne National Laboratory. The sub-project that involves the
NSSPI program consists of safeguarding the URanium EXtraction
(UREX)+1a reprocessing process.
URUREX is a reprocessing process that the United States and the
Global Nuclear Energy Partnership (GNEP) is investigating as an
alternative to Plutonium URanium EXtraction (PUREX). UREX can
greatly reduce the radiological waste while being inherently
proliferation resistance because the plutonium in spent fuel is
kept with minor actinides so it cannot be directly used in nuclear
bomb material. Even though the UREX process is inherently
proliferation resistant it still needs to be safeguarded. Since the
plutonium is never fully separated, as in PUREX, it is harder to
measure than in PUREX.
The UREX +1a process was chosen because the curium is kept with
the plutonium product (See Figure 1 for a schematic). This makes
for an interesting measurement because the number of neutrons from
curium will be several orders of magnitude more than the number of
neutrons from plutonium. The UREX +1a also appears to be a
promising choice if the UREX process is pursued further.
This project is looking at traditional safeguards methods like
those implemented at the Rokkasho Reprocessing Plant and new
methods and detector systems such as the Tensioned Meta-stable
Fluid Detector (TMFD) and methods being developed as part of the
Coupled End-to-End Demonstration (CETE).The TMFD is being
investigated for the use of online alpha spectroscopy to quantify
plutonium in solution in real-time. CETE involves the use of
coupled photon and neutron measurements to quantify plutonium in
spent nuclear fuel. Real-time plutonium measurement paired with
process monitoring is also being investigated.
The goal of this project is to develop detector requirements and
safeguard processes needed for a certain Material Balance Period or
to provide a Material Balance Period for a given safeguards system.
Interested parties include the Department of Energy (DOE), the
International Atomic Energy Agency (IAEA), the Nuclear Regulatory
Commission (NRC), and the facility operators.
Schematic of the UREX+ Process ('Advanced Safeguards Approach for New Reprocessing Facilities' authored by P.C. Durst, PNNL-16674)