U.S. NRC Blog

Transparent, Participate, and Collaborate

Additional Scrutiny at Pilgrim Nuclear Power Plant Set to Continue

Neil Sheehan
Public Affairs Officer
Region I

Last fall, a team of NRC inspectors was tasked with evaluating whether issues at the Pilgrim nuclear power plant that triggered increased agency oversight had been satisfactorily addressed. That team has now returned its findings in the form of a newly issued inspection report.

pilgrimAnd the answer – at least at this point in time – is that Entergy, the Plymouth, Mass., plant’s owner, still has some more work to do.

Specifically, although the eight-member team has determined that, in general, the company’s problem identification, root cause evaluation and corrective action plans were adequate, it has identified deficiencies in the implementation of corrective action plans, as well as in understanding of the issues’ causes.

In its report, the team cites several examples where fixes were not completed as intended or were closed prematurely.

As a result, per agency protocols, the NRC is assigning two “parallel” “white” (low to moderate safety significance) inspection findings to Pilgrim. The findings will administratively replace two “white” performance indicators that initially led to the plant receiving additional scrutiny.

The net effect will be the plant will continue to receive heightened attention until the NRC can perform a follow-up team inspection and is satisfied the concerns have been resolved. The NRC will conduct that additional inspection once Entergy notifies the agency of its readiness for it.

To back up for a moment, the Pilgrim plant’s performance indicator for Unplanned Scrams (shutdowns) with Complications crossed the threshold from “green” to “white” following the third quarter of 2013. Then, in the fourth quarter of last year, the performance indicator for Unplanned Scrams per 7,000 Hours of Operation also changed to “white,” something that occurs if a plant has more than three such shutdowns during the designated period.

This placed Pilgrim in the Degraded Cornerstone Column of the Action Matrix used by the NRC to assess plant performance.

Pilgrim has not had any unplanned scrams since October 2013, and the performance indicators discussed above are currently “green.” But the assignment of the white findings will keep the plant in the Degraded Cornerstone Column pending successful completion of the supplemental inspection.

The NRC intends to discuss the inspection results during the Annual Assessment meeting for the plant. That meeting will likely take place in March near the plant, but a date, time and location have not yet been firmed up.

 

Nuclear Power Plants Ready For Major Winter Storm

Neil Sheehan
Public Affairs Officer
Region I

winterstorm

Update: The Pilgrim nuclear power plant experienced an automatic shutdown, or scram, early Tuesday amid Winter Storm Juno (as dubbed by the Weather Channel). Here is additional information:

Entergy had sequestered staff on-site prior to the storm. The NRC also had an inspector stationed on-site overnight. Reactor power was reduced to 75 percent overnight, per procedures, as the grid experienced voltage fluctuations. Operators started the plant’s two emergency diesel generators and transferred electrical loads for safety systems to those on-site power supplies due to concerns with off-site power.

One of two 345-kilovolt offsite lines was deenergized due to weather concerns. At about 52 percent power, the second 345-kilovolt line that provides off-site power to the plant tripped, resulting in a reactor shutdown, or scram, at about 4 a.m. (Nuclear power plants not only generate power and send it to the grid, they also receive a certain amount of power from the grid for operational purposes.)

A third off-site power line, a 23-kilovolt line, remains available. However, the emergency diesel generators for now remain the primary source of power for safety systems. The reactor was safely shut down, with plant safety systems performing as expected. The exact cause of the loss of the 345-KV power lines is still being investigated.

Entergy intends to take the reactor to “cold” shutdown. NRC inspectors will continue to monitor plant activities and efforts to restore off-site power, as well as any troubleshooting and repair work.

 

The atmospheric stars have aligned once again to produce a powerful mid-winter storm aimed squarely at coastal areas in the Northeastern United States. Officials in a broad swath stretching from New Jersey to Maine have been warning residents to prepare for a blizzard that could produce prodigious amounts of snow, hurricane-force winds and dangerous travel conditions.

There are several nuclear power plants in the storm’s path and the personnel at those facilities will not be sitting back and simply awaiting its arrival. Plant procedures call for multiple checks and preparations in advance of such a winter blast.

Among other things, plant personnel will ensure that doors designed to prevent flooding are ready to perform their task; fuel oil tanks for emergency generators are appropriately filled; and the site grounds do not have loose objects which could become airborne amid strong winds and cause damage.

On a related note, the NRC will be monitoring those preparations and stationing inspectors to keep watch on the plants as they weather the storm. An inspection procedure and checklist dealing with adverse weather protections will guide the inspectors as they conduct those assessments.

It’s important to note that all nuclear power plants have technical specifications that dictate how they have to respond to a significant storm. As an example, if wind speeds are in excess of specified limits, a plant would have to shut down.

Safety at nuclear power plants is never taken for granted, and that is certainly true when storms can present additional challenges for operators. The NRC will be keeping watch until the most potent storm of the winter of 2014-15 to hit the Northeast thus far has headed out to sea.

 

NRC Finalizes Violations for Arkansas Nuclear One

Victor Dricks
Senior Public Affairs Officer
Region IV

The Arkansas Nuclear One power plant, in Russellville, Ark., is coming under increased NRC focus as a result of flood protection problems.

anoBeginning in 2013, Entergy Operations officials and the NRC began extensive inspections of the flood protection program at ANO. Many problems were discovered and are described in a Sept. 9, 2014, NRC inspection report.

All told, more than 100 previously unknown flood barrier deficiencies creating flooding pathways into the site’s two auxiliary buildings were found. These included defective floor seals, flooding barriers that were designed, but never installed, and seals that had deteriorated over time. In one case, a special hatch that was supposed to be close a ventilation duct in the Unit 1 auxiliary building in the event of flooding had never been installed.

In the unlikely event of extreme flooding – a kind not seen since weather records have been kept for the area – significant amounts of water could have entered the auxiliary buildings. This could have submerged vital plant equipment, as well as the emergency diesel generator fuel vaults. The licensee has replaced degraded seals, installed new flood barriers and adopted new measures to better protect the site from flooding.

NRC held a regulatory conference with Entergy officials on Oct. 28, 2014. After considering information provided by the company, NRC determined violations related to flood protection have substantial safety significance, or are “yellow.” (The NRC evaluates regulatory performance at nuclear plants with a color coded process that classifies inspection findings as green, white, yellow or red, in order of increasing safety significance.)

The NRC divides plants into five performance categories, or columns on its Action Matrix. ANO Units 1 and 2 received yellow violations in June 2014 because electrical equipment damaged during an industrial incident increased risk to the plant. Workers were moving a 525-ton component out of the plant’s turbine building when a temporary lifting rig collapsed on March 13, 2013, damaging plant equipment. Those violations moved both units from Column 1 to Column 3 of the NRC’s Action Matrix. The agency increases its oversight of plants as performance declines.

The new violations will lead NRC to reassess whether even more inspection resources need to be focused on ANO. The NRC will determine the appropriate level of agency oversight and notify Entergy officials of that decision in a separate letter.

Hitting the Road – How the NRC Makes Sure Radioactive Material Is Shipped Safely

Bernard White
Senior Project Manager

LWT in Air 2

The NAC LWT transport package Photo courtesy of NAC International

In September 2013, we talked about transportation of spent nuclear fuel and how we know it is safe. This month, we want to discuss the safety basis for transporting other types of radioactive material.

The NRC recently approved a package to transport high enriched uranyl nitrate. This material is left over from the production of medical isotopes used in millions of diagnostic procedures every year. This package is to be used to bring material currently stored in Canada, where the isotopes were made, to the Savannah River site in South Carolina. The shipments are part of a DOE program to take back high enriched uranium from countries to which the U.S. supplied it.

Our review did not address whether the shipment should be made. Nor is it specific to any route. It just looked at whether the proposed shipping package design meets our requirements for safe transport. We rigorously reviewed the information submitted by the cask designer, NAC International. We asked four sets of detailed questions and thoroughly reviewed the applicant’s responses. After two years of review and two face-to-face meetings, we have answers to all our questions and we’re satisfied that the package design meets all NRC requirements for safe transport.

The high enriched uranyl nitrate, which is a liquid, will be transported using special containers that were designed to prevent leakage. To ensure they do not leak, the containers are leak tested after fabrication and prior to transport, each time the container is filled. These containers must also be replaced once they have been in use for 15 months. Together, these requirements give the NRC confidence that the containers will not leak.

These leak-tight containers will be placed into specially-designed packages for transport. This package design has been used for 25 years to safely transport a wide variety of radioactive materials. The inner containers and the outer packaging together make up the transport package.

Our review of this transport package design gives us confidence that, even if there were to be a transport accident, radioactive material will not leak from the package; dose rates will not be high enough to cause harm to anyone; and a nuclear chain reaction will not occur. Packages are evaluated for conditions that mirror normal transportation as well as the forces the package may experience in a severe accident.

The conditions assessed for routine transport include rain, hot and cold temperatures, a drop that may occur during handling, and the vibration that we all feel in a car or riding on a train.

For accident conditions, the package must be shown to be able to withstand forces that are more severe than in a real-world accident. This is done by testing or evaluating the package in a sequence of stringent tests. We discussed these tests in detail in our September 2013 blog.

This package has been shown to be able to safely transport contents that are much heavier and more radioactive than the high enriched uranyl nitrate, including spent nuclear fuel. The dose rates from the package containing liquid uranyl nitrate will be much lower than when the package is loaded with spent fuel.

For all these reasons, the NRC Is confident the package design meets all our requirements for safe transport. We follow the same review process for every transport package design we receive. In every case, we make sure we thoroughly understand the design and all the analyses in the application. We ask questions, if necessary, and often perform our own analysis. In some cases, including this one, we impose special conditions to give added assurance of safety. Only when we are satisfied a design meets every NRC requirement will we issue an approval.

NRC Celebrates A Milestone — 40 Years of Safety and Service

Tom Wellock
NRC Historian

It’s been 40 years since the Nuclear Regulatory Commission began operations on January 19, 1975. To be sure, the agency inherited a mixed legacy from its predecessor, the Atomic Energy Commission. The AEC had established an approach to reactor safety still used today, but critics claimed it worked too closely with the nuclear industry to promote nuclear power. As a new agency, the NRC had to demonstrate that it would be an unbiased, independent regulator.

40yearsOver the years, domestic and international events have challenged the NRC to define what independence meant. A new video on the NRC’s YouTube channel shows us how, in the early years, the essential elements of the NRC’s character were developed and remains today. For example, as the video shows, between 1975 and 1979, the NRC dealt with a major fire at the Brown’s Ferry nuclear power plant in Alabama,  a controversial request to export uranium to India, staff dissent over reactor safety, and tough questioning of its research conclusions regarding the probabilities of nuclear accidents.

From these experiences, the NRC learned that being an independent safety regulator took more than legislation. It meant cultivating a diverse staff, seeking out dissent and heeding critics. Safety research needed to be conducted free of perceived bias, and it learned the limits within which a regulatory agency may act under the United States’ constitutional separation of powers.

All these lessons have proven to be an asset for the NRC when it dealt with its greatest crisis — the 1979 accident at Three Mile Island; and in learning lessons from watershed nuclear events at both Chernobyl and Fukushima. We hope you’ll take a few minutes to watch the video.

Follow

Get every new post delivered to your Inbox.

Join 1,571 other followers

%d bloggers like this: