Criticality Safety Index Limit in a Transit Store

The reasoning is wrong, and the conclusion is wrong on the arithmetic alone.

Current holdings: 5 × CSI 10 = 50. Incoming: 3 × CSI 8 = 24. Combined = 74, against a posted store limit of 50.

The supervisor has confused two different provisions:

• The per-package criticality safety index is 10 and 8 respectively - both under 50, so neither package individually triggers the special treatment.
• The summed CSI in the store is what the limit plate governs. The 50 limit is not a per-package test; it is an accumulation limit on the group of packages held together, and it applies to storage as well as to a conveyance.

So the store is already at its limit before the new consignment arrives, and the placement distance of 2.5 m is irrelevant: distance is a mitigation for the special separation requirement, not a substitute for the accumulation limit. The rule the supervisor half-remembers - the 6 m separation from other fissile material - applies to consignments and packages at or above a CSI of 50 and to stores whose summed CSI would otherwise exceed the limit; it does not licence exceeding the limit by moving things 2.5 m apart.

The lawful options are to hold the incoming consignment outside the store pending a decision, split the holdings across a second approved bay so each remains at or below 50 with the required separation, or return the consignment.

A loaded vehicle in a yard is not an approved store, and the driver's hours are not a nuclear safety argument.

The proposal fails on several counts:

• No accumulation control. The vehicle becomes an uncontrolled store whose CSI content is not counted against any bay limit, and nobody has verified its separation from fissile material elsewhere on site.
• No security or access control. A yard is not a controlled area, and an unattended consignment of fissile material needs one.
• No fire or environmental assessment. The packages are sitting outside the assessed storage envelope.
• The pressure is commercial, not safety-based. Driver hours can be managed by a relief driver, a later collection, or the consignor holding the consignment.

The correct order of operations is: park the vehicle in its designated position away from the store, keep the consignment on the vehicle under whatever interim arrangement the RPO and criticality safety assessor approve, and resolve the store question on the merits. If no compliant interim arrangement exists within the shift, the consignment waits - that is a normal and acceptable outcome. A supervisor who is authorised to accept consignments should also be authorised to say 'not today', and the fact that this one apparently is not is itself a procedural gap worth reporting.

The record has to show that the limit was satisfied at the moment of placement, not that it was satisfied once.

For each placement:

• The CSI total for the bay, recalculated and signed before the packages cross the threshold, including any packages already present and any left over from the same consignment.
• The physical layout as placed - measured separation from other fissile material, stack configuration, and confirmation that the arrangement matches the assessed geometry.
• Label and documentation check: CSI, TI, category, UN number, and consistency between the label and the consignment note.
• Radiation survey of the bay and the aisle, to confirm the added TI does not create a dose-rate problem for staff working nearby.
• Exception record for the arrival that could not be accepted, with the reason, the time, and who authorised the hold. That record is the evidence that the limit was enforced rather than discovered afterwards.

Finally, the limit plate is a control only if the number on it is recomputed when holdings change. A plate reading 50 that nobody reconciles against the actual bay content is decoration, and it is the sort of finding that turns an individual error into a system failure at the next audit.