3A process for separating plutonium and uranium from spent fuel and from each other.
4Shearing involves cutting spent fuel into short lengths to allow its dissolution inside its metallic cladding
5Decladding involves removing the metallic cladding of spent fuel prior to its dissolution.
6Support systems include the SSCs that provide services such as the cooling, lubrication and energy supply required by the safety systems (e.g. cooling water, compressed air).
7A contactor is a liquid–liquid extraction device, such as a pulsed column.
8Including staffing of the reprocessing facility for situations in which a large number of personnel might be unavailable, such as during an epidemic or other event affecting an area where personnel live.
9Highly radioactive liquid waste is also referred to as ‘high level liquid waste’.
10Redundant subsystems may be provided to ensure continuous availability during, for example, maintenance or filter changes.
11A bulge is typically a shielded, stainless steel, windowless, glovebox type enclosure with mechanically sealed openings to allow for the remote removal of items into a shielded transport container via a shielded docking port.
12A cell sump is a designed ‘low point’ in a (normally stainless steel lined) cell base to collect any liquid arising from leakage or overflow
13An air lift or jet lift with disentrainment capabilities is a system or device for separating liquid from motive air or steam with minimum carry-over (entrainment) of activity into the ventilation system.
14Such flasks are sometimes referred to as ‘mobile equipment replacement casks’.
15The phenomenon of such deposition is called ‘plate-out’ in some States.
16The immediate activation of the alarm system is to minimize doses to personnel in case of repeated or multiple criticality events or events with slow criticality kinetics.
17In some States, fires involving nuclear material (e.g. an actinide loaded solvent fire) and other internal fires (e.g. a control room fire caused by an electrical fault) are considered separately and explicitly in the safety assessment for clarity and to ensure that all potential radiological and non-radiological hazards from both categories of fire are adequately addressed.
18Some States have specific regulatory requirements for the design for ‘nuclear loads’ or ‘nuclear lifts’, for example, requiring the use of multi-roped cranes, requiring the application of the single failure criterion, or requiring the maximum load to be a smaller fraction of the test load than for non-nuclear lifts.
19An emergency power supply needs to be provided to enough exhaust fans to maintain the necessary hierarchical negative pressures to ensure dynamic containment. The exhaust systems for which an emergency power supply is needed depend on facility design but typically include: (a) process off-gas fans; (b) glovebox exhausts, where radioactive material of high activity is handled in powder form; (c) cell exhaust fans; (d) some sampling fume hoods, depending on the occupancy; and (e) some area ventilation exhausts that are run at lower speeds.
20Examples of supply systems include air reservoirs, uninterruptible power supplies and diverse cooling.
21Most equipment in reprocessing facilities is operated at negative pressure or close to atmospheric pressure; exceptions are dissolvers and evaporators operating at reduced pressure for safety reasons, certain equipment designed to resist potential violent or runaway reactions, and service supplies (e.g. air, steam).
22Emergency control panels, where justified by the safety assessment, control or monitor the functions necessary during or after a design basis accident. They might not need to be located in a designated supplementary control room.
23At-line instruments are devices that remove a small sample or flow (i.e. proportional sampling) from a process flow or vessel for measurement rather than measuring the bulk material directly.
24In this context, ‘representative and fresh’ means that, where the main process or flow is not being measured directly, it has to be demonstrated (to the same reliability as specified for the SSC by the safety assessment) that the sample is fully representative of the main flow in composition at the time of sampling and measurement (with allowable deviation as specified in the safety assessment) and is delivered to the point of measurement reliably.
25Posting ports are an engineered provision for the transfer of items into, out of and between gloveboxes.
26Bounding cases (also called ‘limiting cases’ or ‘enveloping cases’) are used for the estimation of consequences.
27Foreign material can cause breakdowns, blockages or flow restrictions, either in situ or by displacement to a more restricted location (e.g. inside a pump, valve or ejector nozzle). Foreign material can also cause or facilitate corrosion by forming electrochemical cells or crevices or by impeding heat transfer.
28In commissioning, a graded approach should be applied in accordance with the potential hazard or risk associated with the item being commissioned (or temporarily modified) failing to deliver its safety function on demand at any time in its anticipated operational (qualified) life.
29Upstream sections are parts of the fuel cycle facility or site that provide feeds (e.g. reagent, utilities) to the section being commissioned.
30Downstream sections are parts of the fuel cycle facility or site that receive products or waste from the section being commissioned.
31Support sections are parts of the facility that are ancillary to the section being commissioned but necessary to allow or monitor its operation.
32In some States, the use of natural or depleted uranium may require regulatory approval.
33Tracers are small quantities of very low level radioactive (or inactive) material that mimic the behaviour of the operational material and are used to determine process parameters.
34In some States, the format and content of a commissioning report may be defined by the regulatory body
36Reprocessing facilities typically operate on a continuous basis even when not processing material.
37Examples of access equipment are ladders, scaffolding, access platforms and powered access equipment (i.e. hydraulic platforms).
38Allowing waste (including industrial waste material that is suspected to contain radioactive material) to accumulate in work areas contributes to occupational exposure, both directly as sources and indirectly by impeding work progress. This accumulation of waste can cause delays and complicate the identification of (new) sources of contamination, particularly airborne contamination. It can also lead to action levels for decontamination being raised (owing to an increase in background levels of radiation)
39Intrusive maintenance is maintenance involving a significant reduction in shielding, the breaking of static containment or a significant reduction of dynamic containment, or a combination of these.
40An enclosure is a (usually temporary) combination of a static barrier (containment) supplemented by a dynamic barrier (ventilation) with appropriate entry facilities, which completely boxes in a work area and is sealed, as far as practicable, to local surfaces (e.g. walls, floors) to limit and minimize the spread of contamination. Where possible, enclosures should be modular, with a rigid or heavy duty plastic outer skin that is resistant to damage and a lighter weight, thinner and easily decontaminable inner skin to allow for maximum recycling and reuse and to minimize waste volumes. In some States, the inner skin is called a ‘tent’ or ‘greenhouse’.
41The radioactive fingerprint is the mixture of radioactive nuclides and their ratios that characterize the waste. The radioactive fingerprint may be estimated from the material processed in the area and then confirmed during initial operation of the facility.