Markel Insurance and Willis Towers Watson launched a dedicated nuclear insurance facility in May 2026, structuring it to cover the full project lifecycle from construction to long-term operation. The initiative — described by both parties as a market-first for integrated nuclear risk transfer — targets a widening gap between the global nuclear build-out pace and the specialist underwriting capacity required to cover it. With 70 reactors currently under construction worldwide, the question is no longer whether nuclear insurance will need to scale: it is whether the market can scale fast enough.
A 70-Reactor Pipeline That Insurance Must Now Price
According to the World Nuclear Association’s 2025 Performance Report, 70 reactors representing 78 gigawatts of electrical capacity are currently under construction globally — the highest pipeline since 1990. Of those, 59 are located in Asia, with China alone accounting for 24 under construction and 43 in the planning stage. Nuclear electricity generation reached a record high in 2025. Existing specialist underwriting pools, concentrated primarily in Lloyd’s market syndicates, were designed for conventional light-water reactor designs and cannot efficiently price construction and operational risk for advanced designs or new geographic markets. Per US Nuclear Regulatory Commission guidelines, each reactor site requires a minimum of $1.06 billion in onsite property insurance, with the US sector’s total insurance liability pool exceeding $16 billion.
Why Small Modular Reactors Break the Old Insurance Model
Small modular reactors (SMRs) and advanced reactor designs introduce a fundamental coverage fragmentation problem: the moment nuclear fuel is inserted, the risk profile shifts abruptly from conventional construction peril to nuclear liability exposure. Existing policies, typically structured around either the construction or operational phase, create coverage gaps at precisely this critical transition point. The Markel-WTW facility deploys both quota-share and excess-of-loss structures, designed to bridge the construction-to-operation handover without requiring a separate policy issuance or a coverage pause. This lifecycle integration is the commercial differentiation that existing pool-based arrangements — typically negotiated annual — have not delivered at scale.
Data Centers Are Rewriting Nuclear Demand
Nuclear energy’s resurgence is being driven not only by decarbonization policy but by a more immediate commercial force: the electricity appetite of artificial intelligence infrastructure. According to the International Energy Agency, data center electricity demand surged 17% in 2025 — well above the 3% global average — and total data center power capacity is forecast to nearly triple from 33 gigawatts in 2024 to 120 gigawatts by 2030. In response, technology companies have entered conditional offtake agreements with SMR project developers covering 45 gigawatts of capacity, up from 25 gigawatts at end-2024. These agreements introduce a new class of long-tail operational risk: reactor performance and grid stability now directly affect data center revenue, creating compound exposure that conventional nuclear pool structures were not designed to hold.
What the Facility Means for Reinsurers and Brokers
For reinsurers, the Markel-WTW facility signals that primary carriers are willing to absorb construction-phase and operational property risk at scale — but the tail exposures for novel reactor types and non-standard deployment models (co-located with data centers, offshore, or in emerging nuclear markets) will require excess-of-loss capacity from reinsurers with appetite for uncertain frequency-severity curves. Reinsurers who can standardize SMR lifecycle pricing — particularly around fuel insertion protocols and containment design differences — will gain early-mover advantage. For brokers, the facility creates a new placement category: developers entering nuclear projects for the first time (particularly in markets such as Poland, South Korea expansion, and Southeast Asia) will need integrated risk advisory services that bundle insurance structuring with regulatory compliance. WTW’s co-ownership of the facility positions it to capture this demand before competitors build comparable nuclear practice depth.
