LONDON—Willis Group Holdings P.L.C. has developed an insurance product to cover business disruptions resulting from exclusion zones implemented to contain damage from incidents at nuclear power plants.

The coverage was developed by the Willis Global Markets International division in response to the exclusion zone that Japanese officials established around the Fukushima nuclear power plant as a result of radiation leaks after the March 11 earthquake and tsunami.

“This started with the Japan earthquake and tsunami,” said David Reynolds, executive director and client advocate at Willis Global Markets International in London. “A lot of buyers’ coverage was tested and, in some cases, found to be wanting in this event.”

Bespoke product

The Willis-designed policy will respond to exclusion zones imposed around nuclear plants as a result of natural catastrophes, and those prompted by other events or failures at a nuclear plant. It covers disruptions resulting because of client locations in exclusion zones, and disruptions that companies face because key suppliers or customers are located in those areas.

Each policy essentially will be custom-written, Mr. Reynolds said, based on the particular circumstances and exposure of the client. “It’s a bespoke product,” he said. “Every coverage is going to be different.”

Likewise, limits will vary by customer, he said. “We establish the client’s needs and then we see what we could get,” Mr. Reynolds said.

Information backs coverage

In assessing clients’ supply chain exposures for the exclusion zone coverage, Willis plans to “go beyond first tier” in identifying supplier risks, said Graham Knight, managing director with Willis’ power and utilities practice in London. “The more information we can provide on customers’ suppliers, the more chance we have to get the client broader coverage.”

Mr. Reynolds said Willis has insurers in place to underwrite the exclusion zone coverage, but said the broker is keeping them confidential. “This type of insurance is probably something the bulk of the market wouldn’t want to write because of the wariness of a nuclear event,” he said.