Evaluating the decommissioned status of a LWR and RRCA facility to determine level of effort needed to safeguard facility

The International Atomic Energy Agency (IAEA) conducts comprehensive design information verifications (DIV) to affirm the declared status of a facility. When the IAEA verifies the conditions at a facility that is revising its status, it needs to have a technical basis for confirming that the facility has changed its declared status. There is little difficulty in verifying a change of status from 'operating' to 'closed-down' since that is mainly a matter of verifying that nuclear material has been removed from the facility. This is more of an inspection activity than a DIV. The IAEA has found that verifying a change in status from 'closed-down' to 'decommissioned' is more complicated. The distinction between a 'closed-down' and 'decommissioned' status is important because a decommissioned facility is subject to less stringent safeguards measures (actually no measures under traditional safeguards), so the Agency must be confident that the decommissioned facility cannot be restarted and misused (e.g., no inspections if decommissioned; complementary access (CA) possible in a state with the Additional Protocol in force). INFCIRC/540 defines 'Decommissioned' as meaning that residual structures and equipment essential for the facility's use have been removed or rendered inoperable. The IAEA has compiled lists of 'essential equipment' for major facility types to aid inspectors in DIV inspections. However, the definition in INFCIRC/540 does not state how much of the essential equipment must be removed or rendered inoperable in order to consider the facility as a whole to be decommissioned. A facility may be 'mothballed' with many pieces of nuclear steam supply system (NSSS) equipment still in place. The IAEA desires to develop guidelines to identify the essential equipment that must be removed or rendered inoperable for major facility types in order to classify a facility as decommissioned for safeguards purposes. The IAEA wants to compile factors such as the time, cost, and practicability of re-activating a facility as compared to building a new one elsewhere. Inspectors can use these guidelines when confirming that a facility is 'rendered inoperable'. The authors will be conducting a field study to identify criteria that the Agency can use to confirm the decommissioned status of a facility. The authors will investigate two facility categories: Light Water Reactors (LWRs) and Research Reactor and Critical Assemblies (RRCA). Three RRCAs located at Brookhaven National Laboratory will be included in the study. These facilities include a graphite-moderated natural and enriched fueled reactor, a small water-cooled LEU fueled reactor, and a D2O moderated and cooled HEU fueled reactor which provide a diverse group of RRCAs. As regards commercial LWRs, both BWR and PWR types in the U.S. will be considered in the study. This paper will address our preliminary recommendations for identifying criteria to verify the decommissioned status at both the RRCAs and LWRs. We will cover the safeguards effort needed to insure that a facility is not reconstituted and material processed before the IAEA can detect this undeclared activity in a timely fashion. (author)