Verifying the Research

Many research reactor facilities contain hot cells. These containment chambers shield workers from nuclear radiation; the worker stands outside the cell and uses manipulator arms to safely handle the equipment and nuclear materials located inside the chamber.

Hot cells are most often used for isotope separation for medical purposes, but they can also be used for small-scale plutonium extraction from the irradiated fuel produced by a research reactor. IAEA safeguards inspectors are trained to detect plutonium extraction.

A smaller number of research reactors use high enriched uranium (HEU) — uranium enriched to greater than 20% uranium-235 — which is another material that can be used to produce nuclear weapons. Although many research reactors are already converted to use low enriched uranium (LEU) — which is not directly usable for nuclear weapons — IAEA safeguards inspectors still check all nuclear material at a research reactor facility in order to verify the correctness and completeness of the State’s declaration.

“Due to the differences in the design and use of research reactors, there is no general checklist to satisfy safeguards requirements at such facilities,” said Tadjer. “Instead, we train our inspectors to look for any signs of misuse at research reactors and the diversion of nuclear material. For inspectors, it’s about spotting inconsistencies and then knowing the right questions to ask.”

However, it is not solely the work of the IAEA inspectors to apply safeguards, as States also have certain requirements they have to meet. The IAEA offers States assistance in meeting these requirements in terms of incorporating safeguards into the design of a facility, implementing nuclear material accountancy and meeting the legal requirements of implementing safeguards. Such assistance includes guidance on building safeguards considerations into the design of research reactors. The IAEA also offers in-country advisory missions to support State systems of accounting for and control of nuclear material (SSAC) in meeting their obligations.

By considering safeguards requirements early in the research reactor design process, future demands on the facility operator for nuclear material verification can be reduced. For instance, the possibility of applying remote monitoring is cost effective and maintains safeguards effectiveness while reducing the need for inspector activity on-site. One example of remote monitoring is the use of an advanced thermohydraulic power monitor that assesses coolant flow and heat extraction to calculate the reactor’s plutonium production. By knowing how much plutonium is produced by the reactor over a specific time period, inspectors can amend the frequency of inspection accordingly, thereby saving time for both the inspector and the operator.

“To apply safeguards at research reactors, as with applying safeguards at any nuclear facility, cooperation between the State and the IAEA is very important,” said Tadjer. “By working together and applying modern technology, such as the advanced thermohydraulic power monitor, the IAEA can more effectively and efficiently verify that nuclear material remains in peaceful use.”

This article was also featured in the IAEA Bulletin on Research Reactors published in November 2019.