BY ANGELJEAN CHIARAMIDA
---- — SEABROOK — Political pressure to close Seabrook’s nuclear power plant continues to mount, but the Nuclear Regulatory Commission says it will not make a decision until issues with degrading concrete are fully understood.
Eight members of the Massachusetts Congressional delegation have written to the NRC requesting it make no decision on extending the license for NextEra Energy Seabrook’s nuclear power plant until the concrete problems at the structure is well understood and remedied if necessary.
The letter was signed by U.S. Rep. John Tierney, D-Salem, both of Massachusetts U.S. Senators, Edward Markey and Elizabeth Warren, as well as Representatives James McGovern, Stephen Lynch, William Keating, Niki Tsongas and Joeseph Kennedy, III, all Democrats. It was mailed to Allison Macfarlane, chairwoman of the Nuclear Regulary Commission on Wednesday, the same day the NRC held an informational meeting in Hampton, N.H. to update the public on Seabrook Station’s alkali silica reaction concrete degradation issue.
On Wednesday, NRC Spokesman Neil Sheehan said the agency had just received the letter and had to review it before providing a full response. But, he added, the NRC had dealt with this request from officials and others before.
“We’ve been engaged in a comprehensive review of the concrete degradation issues at Seabrook for several years,” Sheehan said. “And we’ve made clear that we will not issue a decision on the plant’s license renewal application unless and/or until NextEra develops a satisfactory long-term plan for addressing the condition. The focus of our meeting (Wednesday night was) on where the NRC and company evaluations currently stand.”
Alkali-silica reaction, or ASR, is a slow chemical reaction between the alkaline cement and reactive silica found in some aggregates used to make concrete that happens when moisture is present. Found for centuries commonly in concrete dams and bridges, ASR forms a gel that expands, causing micro-cracks — similar in size of a spider web filament — that affect concrete properties. Historically, ASR can take decades to show up in concrete structures.
The problem was not discovered at Seabrook Station until June 2009 when NextEra itself identified areas of ASR in underground structures at the power plant and reported the findings to the NRC. Found first in the 2-foot thick, steel rebar reinforced concrete walls of an electrical tunnel about 40 feet below ground, after further investigation it was determined that ASR is present in 131 areas throughout the power plant.
Since its discovery, the NRC has repeatedly, including at Wednesday night’s meeting, assured the public that the ASR has not affected the safety of Seabrook Station. The plant and its walls are still structurally sound, NRC officials said, because the parts of the 2-foot thick walls affected still meet federal standards for load-bearing capacity due to the lattice of steel rebar within the walls. The plant was built with such a large margin of safety, NRC engineers say, that the physical integrity of the structure remains sound and safe.
The NRC has conducted a number of ASR related in depth inspections since the initial discovery, to make its determination that the plant is currently safe, according to David Lew, NRC Deputy Regional Director of Region 1, the branch of the NRC that oversees Seabrook Station. In addition, Lew said, NextEra has contracted with the University of Texas at Austin to determine the impact ASR could have on the long-term structural integrity of the plant, which is currently licensed to operate until 2030.
However, ASR has become a huge concern for many antinuclear advocates, as well as for local, state and federal officials, since NextEra filed an application in 2010 with the NRC requesting a 20-year extension of its operating license from 2030 to 2050.
“Although testing and monitoring of the (ASR) problem has been undertaken since (its discovery),” the Congressional delegation wrote, “it seems unlikely that would enable the licensee (NextEra) to predict any future impact of ASR.”
Even though ASR can be found in many bridges, dams and airport runways throughout the nation, Seabrook Station is the first nuclear power plant in the United States to report its presence in its concrete structure. Nuclear power plants in Canada and Belgium have also reported the presence of ASR.