An Inspector’s Perspective On the Control Rod Drive Mechanism Housing Flaws At Palisades

Elba Sanchez Santiago
Materials Engineering Inspector
NRC Region III
 
Elba Sanchez Santiago is a Materials Engineering Inspector in the NRC's Region III.
Elba Sanchez Santiago is a
Materials Engineering Inspector in the
NRC’s Region III.

There has been a lot of interest lately in the flaws that were recently found in the control rod drive mechanism (CRDM) housings at the Palisades nuclear plant, near South Haven, Mich. I want to share my direct experience with the NRC’s thorough and independent evaluation of this issue.

First, some background. The control rod drive mechanism moves control rods inside the reactor to control the level of nuclear chain reaction. The housing is a metal tube around the control rod drive mechanism, which is connected to the control rod and prevents leakage of reactor water into containment.

According to a commitment made in 2012, the plant conducted inspections of 45 CRDM housings in this reactor and found flaws in 17 of them. Palisades committed to these inspections after the discovery of a crack in one of the housings resulted in a plant shutdown in 2012.

Because of my expertise as a materials engineering inspector, I was dispatched to Palisades after it shut down in 2012. I was to evaluate the plant’s response to the discovery of the through-wall crack. As a member of a special inspection team that further evaluated this issue, I reviewed the plant’s testing of eight additional CRDM housings and their corrective actions. Even though no other cracks were found, the plant committed to further evaluate the condition of the housings during the 2014 refueling outage.

I came to Palisades before the current outage started to evaluate the site’s inspection methodology, work procedures, tooling and personnel qualifications. When the examinations started, I observed some of the actual testing and evaluated the results. To date, there is no evidence of leakage resulting from the flaws. I will remain onsite providing oversight over the plant’s actions until the issue is resolved.

Since the issue first came to light in 2012, I have been working with a team of other inspectors and specialists in Region III and the headquarters office in Rockville, Md., to make sure we ask the necessary questions to understand the plant’s methodology and assessments, and independently verify the conclusions.

Our in-depth independent reviews will continue until the plant completes the necessary repairs and takes proper actions to make sure the CRDM housing flaws do not lead to a significant safety concern. The results of our inspections will be documented in a publicly available inspection report.

Moments in NRC History: The Founding of the NRC

Thomas Wellock
NRC Historian
 

In October 1974, President Gerald Ford signed the landmark Energy Reorganization Act splitting the Atomic Energy Commission into two agencies effective January 19, 1975.

President Gerald Ford signs the legislation that created the NRC.
President Gerald Ford signs the legislation that created the NRC.

Today, almost 40 years later, some still confuse the Department of Energy and the NRC. But the independence of the NRC from DOE was – and is – no small matter. By separating the regulator from the promoter, the U.S. led the way in ensuring credible oversight of the nuclear industry.

This evolution is explored in my latest “Moments in NRC History” video, found on the agency’s YouTube channel. This video explores how the AEC — a storied and powerful federal agency – began “falling apart” in the words of one Congressman.

The video has archival photos to illustrate the change from a Cold War mentality to the fall-out over radioactive fallout from weapons testing in the 1950s to the controversy over nuclear power plant sites in the 1960s and ‘70s.

The 1974 legislation sought to ensure NRC’s independence with a five-member commission, bipartisan commissioner appointments, an office of regulatory research, and a substantial research budget. The NRC staff also gained greater independence than the AEC staff had on regulatory decisions.

The new agency was met with enthusiasm from both the nuclear industry and antinuclear activists – although for different reasons. While the NRC was born out of a consensus that independent regulation was essential, how could it satisfy the divergent expectations? Many decades later, that question still confronts the NRC.

I hope you’ll take a few moments to watch this latest video. I’ll explore how the new agency responded to the challenge in a future installment of “Moments in NRC History.”

%d bloggers like this: