Limerick Nuclear Plant’s Re-Licensing Application Circumvents Safety Analysis Requirements

NRDC Files Petitions to Intervene in the Limerick Nuclear Plant Operating License Renewal Application, Citing Obsolete Accident Mitigation Study

WASHINGTON D.C. (November 28, 2011) – Exelon Generation, the owner of the Limerick nuclear power plant outside of Philadelphia, is seeking federal re-licensing of its plant without updating a 1980s-era accident mitigation study, due to an inappropriate exemption received from the Nuclear Regulatory Commission (NRC), according to petitions filed last week by the Natural Resources Defense Council.

“The tragedy in Japan has resulted in a hard look at the safety of nuclear plants worldwide and is providing critical new information that can help prevent future disasters. We need to learn from that failure, not ignore it,” said Christopher Paine, director of the nuclear program at NRDC. “The Limerick nuclear power plant’s safety analysis for mitigating unlikely but severe accidents is decades out-of-date. Re-licensing it now without a fresh analysis of potential safety upgrades would be a reckless decision, especially given that the current operating licenses for these twin units don’t expire until 2024 and 2029. There is ample time to take a fresh look at safety improvements.”

The NRDC petitions contend that Exelon’s license renewal application is deficient because it relies on outdated and insufficient safety and risk information and fails to fully consider the alternatives to re-licensing Limerick as required by the National Environmental Policy Act (NEPA).

All U.S. nuclear plants are required to conduct a critical safety review known as a Severe Accident Mitigation Alternatives, or “SAMA,” analysis to determine potentially cost-beneficial operational safety upgrades at nuclear plants. The last analysis for Limerick, completed in 1989, relied upon population data from 1980 and therefore didn’t take into account evacuation planning and the health risk from radiation exposure for up to 1.4 million additional people now living downwind in the Philadelphia-Wilmington-Newark metropolitan area.

“An outdated safety analysis that ignores the population growth in the region is unacceptable if an emergency evacuation at Limerick becomes necessary,” said NRDC scientist Jordan Weaver.  “Some common sense planning is needed here.  What was acceptable in 1989 is not good enough for the next 30 to 40 years.”

Exelon Generation’s old severe accident mitigation analysis also doesn’t contain an assessment of economic damage resulting from a radioactive plume, a key feature of the SAMA reviews at other U.S. nuclear plants and one that’s especially relevant to Limerick given its proximity to economic centers. And most importantly, Limerick’s 1989 SAMA study doesn’t take into account hundreds of potential safety improvements based on the greater understanding of nuclear power plant operations over the last three decades and in the aftermath of the Japanese disaster.

Exelon’s two Boiling Water Reactors (BWRs), which are of similar design to the stricken units at Fukushima, are located 30 miles northwest of Philadelphia in a densely-populated region on the Schuylkill River with portions of Berks, Chester and Montgomery counties in the 10-mile emergency evacuation zone. Due to Limerick’s location, the potential impact of a severe accident would be far greater than at most other U.S. nuclear plants. Over eight million people now live within 50 miles of Limerick, an area within which the NRC told Americans to leave during the Fukushima accident this spring.

While a tsunami would not occur at Limerick, the same type of malfunction – a loss of primary and back-up power supplies – could occur at Limerick due to other causes.  In fact, multiple U.S. nuclear reactors have undergone emergency shutdown this past year as a result of tornado, flood, earthquake and hurricane.

“The Fukushima disaster fundamentally happened because the nuclear plant lost power and could no longer keep its reactor cores cool even after emergency shutdown,” said Matthew McKinzie, senior scientist at the NRDC. “This type of power loss can happen in a number of ways beyond the one-two punch of an earthquake and tsunami.”

The NRDC petitions were filed with the U.S. Nuclear Regulatory Commission’s Atomic Safety and Licensing Board (ASLB).  They seek approval for NRDC to become interveners in Exelon Generation Company’s application to renew the operating license for the Limerick Generating Station and request an administrative hearing before the ASLB


A SAMA analysis is a comprehensive accident consequence and safety upgrade assessment required of nuclear plant operators by the NRC when they seek to re-license nuclear reactors. In a SAMA study, the benefits of a particular safety upgrade to mitigate the human health, economic and environmental impacts of a nuclear accident are weighed against the financial cost of the upgrade, and typically hundreds of potential safety upgrades are evaluated.  So far 18 SAMA studies have been conducted for the re-licensing applications of BWRs in the United States, and on average four and as many as 11 cost-beneficial safety upgrades have been identified at each plant.

Exelon Generation and the NRC claim that Limerick is exempt from performing a SAMA analysis for re-licensing due to the existence of a court-ordered study from 1989 for its original licensing, which was then termed a Severe Accident Mitigation Design Alternatives or “SAMDA” analysis.