The currently proposed SMRs (IAEA, 2014) have new design features and technologies that may require new tools and measures for safeguards and security. Some safeguards and security considerations for SMRs may be different from those for a large reactor.

For example, there may be issues associated with the fuels such that the existing accountancy tools and measures may need to be modified or further developed for reactors using non-conventional fuel types. Further, issues may arise about new fuel loading schemes, as reactor cores with extremely long lifetimes may require innovative surveillance tools and measures, and long-life sealed core replacement may present novel accountancy challenges.

International safeguards typically verify the operator’s declaration of activities with nuclear material. These declarations address the receipts, shipments, storage, movement, and production of nuclear material. Inspections depend on the material

type and whether the material is irradiated. The IAEA state level approach (IAEA, 2010) will in addition take into account the technical capabilities of the state including the possible existence of other nuclear activities (including commercial or academic R&D) and the location of the facilities.

Safeguards considerations will take into consideration differences in various factors; i. e., the accessibility to the nuclear material, whether the reactor facility is operated continuously, how the reactor facility is refueled, the location and mobility of the reactor facility, and the existence and locations of other nuclear facilities in a given state.

For example, for nuclear materials that are normally not available to the host state, if the vendor state delivers a sealed unit that operates until the vendor replaces it with a new one, at some later time, and there is no storage capability for used fuel in the host state nor equipment to handle used fuel — this could raise issues, such as whether the reactor can not only be ‘sealed’ by IAEA and treated as an item, but whether remote monitoring of the seal can readily detect any attempt to open the reactor. When comparing equivalent generating capacity, i. e., many SMRs with the same total capacity with one large LWR, inspection issues would deal with whether SMRs will be co-located or separated at different sites. Additional issues would deal with their refueling schemes and whether they would be different, and whether there would there be separate used-fuel storage for each module.

In the case of many small reactors in remote (e. g. arctic) separated locations compared to one large centrally located reactor with a large electric grid, it would be necessary to consider inspector ease of access to the remote site as well as the possibility of building an electrical distribution grid. Other considerations are: load — dependent vs. base-load reactors; stand-alone sole source of energy supply; offshore SMRs on floating barges tied to a state/regional grid; control vs. ownership.

The following considerations could apply to any new installation, including SMRs:

• Fuel leasing or supply arrangements that avoid on-site storage of fresh and/or used fuel.

• The isolation of the site or mobility of the reactor (sea or rail) might be a factor. Consideration should be given to access issues for both inspectorate and the adversary.

• Remote monitoring: There should be discussions between the operator/State/IAEA about small reactors which evaluate the potential of remote monitoring, including transmission of data off site.

• Will there be a different approach to physical protection and how might that affect the safeguards tools?

• Will the site or nearby sites have more or less ancillary equipment like hot cells, pin replacement capability, fuel storage, or nuclear research activities?

• Will the containment features be shared by multiple units; will there be underground containment?

The following discussion pertaining to physical security is derived in part from ideas in a white paper by the Nuclear Energy Institute (NEI, 2012), but with some change in emphasis.

Some of the same features that are being included in the design of SMRs as safety improvements may also improve their protection against physical threats. One feature common to some SMR designs is a compact reactor coolant boundary, contained mainly within the reactor pressure vessel (RPV). This feature may enhance the safety of light-water reactor-type SMRs, because large-break loss-of-coolant accidents (LOCAs) may not need to be considered for these reactor types. This could also be potentially advantageous against deliberate acts.

Some SMRs may have a number of passive physical barriers and simplicity in systems required for safe shutdown. These may include such features as RPVs and containment vessels located underwater or below grade, the reactor building located partially or completely below grade, and fewer safe shutdown systems and components requiring physical protection. The below-grade installation of some SMRs may provide additional security benefits, such as minimizing aircraft impact, limiting access to vital areas and the communication ability of adversaries. These features may provide a means of enhancing security system effectiveness against radiological sabotage. Use of the traditional multilayered defensive approach of deterrence, detection, assessment, delay, and interdiction can potentially be used effectively for physical protection of SMRs. Deterrence, detection, and delay concepts could be addressed in the early design phase of a facility in order to provide sufficient response time for on-site security force response. The ability to rely on an effective onsite response to a security threat is a potentially important factor that should be considered at the initial conceptual design phase to ensure sufficient intruder delays are included.

Examples of methods for extending adversary delay times, which in principle also apply to large plants that can be incorporated into SMR designs include:

• locating and configuring vital components so that gaining access to these components is extremely difficult and time consuming for an intruder;

• locating and configuring critical safety systems so that there is no capability to destroy a target set from a single location;

• incorporating multiple layers of delay barriers against intruders and minimizing the number of access points to areas containing vital assets.

To the extent that SMRs are in the early stages of design or conceptual development, the above bullet items could be considered without the need to do potentially costly retrofits if these are considered after a plant is built.

One should also consider physical security system design options which minimize human involvement in security events (i. e., lower security risk profile), minimize impact of necessary future system modifications, and maximize adversary delay times. Examples include:

• designing the facility with minimum access points and multiple passive barriers based on a defense-in-depth approach to physical security;

• using redundant detection, assessment and delay systems;

• using modular capabilities in physical security systems to minimize impact on station security staffing for system maintenance as well as upgrades needed to address system technology obsolescence and potential future increased design basis threats.

Again, to the extent that SMRs are in the early stages of design or conceptual

development, the above bullet items could be considered without the need for potentially costly retrofits if these are considered after a plant is built.

A regulatory issue of importance related to physical security of SMRs is security staffing. Security staffing directly impacts operations and maintenance (O&M) costs and as such constitutes a significant financial burden over the life of the facility. SMRs are significantly smaller in size and system complexity which translates to improving security efficiency.

Key features of the physical protection programs that affect staffing expectations for nuclear facilities include:

• defense in depth using graded physical protection areas: increasing protection and control as vital equipment is neared (with well-defined boundaries);

• access authorization programs;

• robustness of intrusion barriers;

• alarm assessment to distinguish between false or nuisance alarms and actual intrusions and to initiate response;

• likely response to intrusions.

As discussed above, some general considerations for PR&PP assessments of SMRs are as follows.

• Smaller power reactors have smaller radiological inventories and thus potentially smaller releases during off-normal conditions.

• Smaller reactors have a smaller physical footprint, which can potentially lead to a smaller security force and fewer needs for surveillance and otherwise reduces the target area size.

• Some designs have potentially longer fuel cycles, which can potentially lead to fuel being inaccessible for longer periods of time.

• Smaller designs have potentially constrained ingress and egress, which makes detection and monitoring simpler.

• Ease of fuel assembly transport for some designs, which needs to be recognized and assessed.

• Higher enrichment levels for some SMRs relative to conventional light-water reactors, which need to be recognized and assessed.

• Remote locations of facilities present new challenges for inspections.

• Transportable facilities present unique technical and institutional issues relative to stationary facilities.

• Potential for a reduced security force.

• Potential for a reduced emergency planning scope.

The discussion given above applies generally to many SMRs currently under consideration. For the integral pressurized water reactors (iPWRs), which is the focus of this section of the Handbook, there are some distinguishing characteristics that may be pertinent for non-proliferation and security. Since the iPWRs are based on the larger, more familiar PWRs, it can be anticipated that international safeguards for the iPWRs could be developed from the basis of the current safeguards for large PWRs. Less conventional SMRs, of more novel designs, may require the development of additional specialized safeguards approaches. For iPWRs that have fuel enrichments similar to large PWRs, the material attractiveness considerations should be similar.

If the iPWRs operate with closed reactor vessels in a manner similar to large PWRs and have comparable fueling periods, this then offers a comparable barrier to fuel accessibility. If the iPWR can maintain a small physical footprint relative to other SMR designs then this could be a security advantage.