An Outage Twist: Degraded bolts at New York Nuclear Plant Warrant Attention

Neil Sheehan
Public Affairs Officer
Region I

When the Indian Point Unit 2 nuclear power plant entered a refueling and maintenance outage in early March, the to-do list included a task born of industry operating experience, both in the United States and overseas.

BaffleBoltsGraphic1_cleanbigfontSpecialists were geared up to check on the condition of bolts employed in the reactor vessel at the Buchanan, N.Y., facility. These are the kind of bolts you likely wouldn’t find at your local hardware store. Rather, they are made of a stainless-steel alloy capable of withstanding decades’ worth of neutron bombardment, as well as extraordinarily high temperatures and pressure.

Measuring about 2 inches in length and 5/8ths of an inch in diameter, the bolts hold in place a series of vertical metal plates. Known as baffle plates, they help direct water up through the nuclear fuel assemblies, where it is heated and subsequently used for power production.

The baffle plates are attached to eight levels of horizontal plates called baffle-former plates, which are in turn connected to the reactor core barrel.

As far back as the late 1980s, cracking was identified in baffle-former bolts – the bolts securing the baffle plates to the baffle-former plates — in pressurized-water reactors (PWRs) in France. (Both Indian Point Units 2 and 3 are PWRs.) The degradation is caused by what is known as irradiation-assisted stress corrosion cracking.

In response, the U.S nuclear industry began checking on these bolts in a small number of domestic PWRs on a sample basis.

The NRC staff also made use of a communications tool called an Information Notice to advise U.S. plant owners of what had been observed in Europe. A March 1998 notice let U.S. plant owners know that the baffle-former bolt cracking reported in foreign PWRs had occurred at the juncture of the bolt head and the shank, a location not accessible for visual examination.

Several U.S. plants subsequently evaluated their baffle-former bolts and in some cases replaced a sizable number.

Jumping ahead, the Electric Power Research Institute developed a standard industry program for the aging management of PWR reactor vessel internals and submitted it to the NRC in January 2009. The NRC staff approved the approach in an agency safety evaluation issued in December 2011 and then published in January 2012 as MRP-227-A. (MRP is short for Materials Reliability Program.)

Under this new standard, U.S. PWRs were to conduct an initial ultrasonic examination of all of their baffle-former bolts when the plant had between 25 and 35 effective full power years of service.

This is exactly what was being done at Indian Point Unit 2 during the current outage. It was adhering to the standards of MRP-227-A. In the course of this review, it was determined that 227 of 832 baffle-former bolts at the plant were degraded, which means any indication of cracking. What’s more, two bolt heads were missing.

The number of degraded baffle-former bolts was the largest seen to date at a U.S. reactor.

Entergy, Indian Point’s owner, is in the process of analyzing the condition and replacing the degraded bolts. It will also assess any implications for Indian Point Unit 3, though that reactor is believed to be less susceptible to the condition for several reasons, including fewer operational cycles.

As for the NRC, we will independently review the company’s analysis and bolt-replacement plans to ensure safety. The results of those reviews will be documented in an upcoming inspection report for the plant.

We have already had a metallurgical specialist on-site reviewing the company’s evaluations of the bolts and have agency experts reviewing the matter.

More information will be forthcoming on the issue. However, it’s important to note that the NRC staff will ensure the condition is fully understood and addressed prior to the plant returning to service. The NRC staff will also consider all available information in evaluating if changes are needed to the current inspection programs for these bolts across the industry.

 

Indian Point 3 Timely Renewal

Diane Screnci
Sr. Public Affairs Officer
Region I

It’s been more than eight years since Entergy filed an application requesting that the NRC renew the operating licenses for Indian Point Units 2 and 3. And, a final decision is still a ways off.

indianpointUnder NRC regulations, if a company submits a sufficient application for a renewed license at least five years before the expiration of the current license, then the request is considered “timely” and the facility is allowed to continue operating under its current license until the NRC issues a decision on the license renewal request.

On December 13th, Indian Point 3 will enter the period of “timely renewal.”  Entergy submitted a license renewal application for both Indian Point Units in April 2007, meeting the timeliness provision. The Unit 3 license would have expired December 12, 2015. This doesn’t mean the unit will be operating without a license. Rather Unit 3, like Unit 2 (which entered timely renewal in September 2013), will continue to operate under its existing license.

The Atomic Energy Act specifies that operating licenses can be issued for up to 40 years and allows license renewals in 20 year increments. Thus far, the NRC has issued renewed licenses to 81 reactors. Typically, it takes about 22 months for the staff to reach a decision on whether to renew a license – longer if there’s a hearing. In the case of Indian Point, though, the process has taken longer than projected, due in part to the large number of contentions the parties have raised in the hearing.

Although a final decision on the application hasn’t been reached, the NRC staff has measures in place to provide assurance the facility will continue to operate safely during this time period.  We’ll continue to carry out our extensive regulatory and oversight activities. NRC inspectors, including the three on-site Resident Inspectors and specialist inspectors from the Regional office, will continue their duties during this period, providing independent oversight of the facility on a continual basis.

In a September 28 letter to the NRC, Entergy confirmed that the Unit 3 license renewal commitments required to be in place prior to entry into the period of extended operation were complete. In October, Entergy certified that the Indian Point 3 Updated Final Safety analysis report had been updated to incorporate aging management programs for the unit. In response, that same month, we completed an inspection to review the activities Entergy has taken to prepare for operating in timely renewal and found that the processes and commitments had been properly implemented.

While it might be some time before the Commission reaches a final decision on license renewal at Indian Point, our independent oversight of the facility will continue uninterrupted while in “timely renewal.”

NRC Carefully Assessed Issues Associated with New Pipeline at Indian Point

Neil Sheehan
Public Affairs Officer
Region I

Mention nuclear power plant and new natural gas pipeline in the same breath and it may not be surprising if some ears perk up.

inptSuch was the case with a plan by Spectra Energy to install a 42-inch-diameter natural gas pipeline that would cross a portion of the Indian Point nuclear power plant site, in Buchanan, N.Y. One of the most salient questions to arise has been whether a rupture of the pipeline could adversely impact the safety or shutdown of the two operating reactors at the site.

The NRC’s conclusion, based on a thorough peer-reviewed analysis, is no.

First, however, it’s important to understand the limitations on the NRC in this complex interstate project. The agency’s role is restricted to ensuring the safe operations of the Indian Point facility; we cannot usurp the roles and responsibilities of other federal, state and local government agencies.

Other agencies involved in the proposed pipeline expansion include the Federal Energy Regulatory Commission (FERC), which is the lead agency for evaluating applications to construct and operate interstate natural gas pipeline facilities; the Pipeline and Hazardous Materials Safety Administration of the Department of Energy; and the Environmental Protection Agency. There are also many state and local government agencies that have separate responsibilities.

Indian Point has for decades had two natural gas pipelines – one 26 inches in diameter and the other 30 inches– running through the property. The Algonquin Gas Transmission Co., a subsidiary of Spectra Energy, built the 26-inch line in 1952 and the adjacent 30-inch line in 1965. Operating licenses were granted to Indian Point Units 1, 2 and 3, in 1962, 1973 and 1975, respectively. The new line would be installed across a more southerly section. (Plans also call for the 26-inch line to be removed from active use at the time the new line begins operating.)

The 42-inch line would not be located within the plant’s Protected Area – the highly secure section where the reactor buildings, spent fuel pools and other key structures are located. Instead, it would traverse the site about a quarter-mile from the Unit 2 and 3 reactors.

There will also be special precautions to enhance the safety of the piping that will be located closest to Indian Point to further limit the already very low potential for a gas pipeline rupture. For one, the steel pipe will have a wall thickness of almost three-quarters of an inch and will buried at least 4 feet deep, under engineered backfill. The line will have additional corrosion protection and all of its welds will be carefully examined.

Reinforced-concrete protective mats will also be placed over the section of the pipeline closest to Indian Point, providing additional physical protection. Warning markings will drive home the message that excavation in that area is a bad idea. Accidental ruptures during excavation work are one of the most frequent causes of pipeline failure.

Entergy Nuclear Operations Inc., the plant’s owner/operator, was required under NRC regulations to perform a site hazards analysis to evaluate how plant operations could be impacted by a rupture of the pipeline. The company determined the plant could safely shut down and, more broadly, that the pipeline would not pose an undue risk in terms of the facility’s safe operation.

inptThe NRC did not accept this analysis at face value. The agency conducted an independent confirmatory analysis. This evaluation, which assumed a complete rupture of the pipeline, concluded the plant could either continue to safely operate or temporarily shut down.

In addition, NRC inspectors performed visual assessments of the proposed pipeline routing to confirm assumptions used in Entergy’s analysis report. They also reviewed the qualifications of the contractor who carried out the company’s analysis and that Entergy’s acceptance of the report was consistent with its quality assurance program standards.

A discussion of the NRC’s inspection and analysis can be found in an inspection report issued on Nov. 7, 2014. In it, the NRC staff states that “the staff determined Entergy had appropriately concluded that the proposed pipeline does not introduce significant additional risk to safety-related structures, systems and components at Indian Point Units 2 and 3, and therefore the change in the design bases external hazards analysis associated with the proposed pipeline does not require prior NRC review and approval.”

After consideration of all of this information, the NRC determined the two Indian Point reactors could safely operate or shut down if a rupture were to occur on any portion of the proposed pipeline where it would traverse Entergy’s property. The NRC shared these findings with FERC. That agency approved Spectra Energy’s proposal to build the expanded pipeline on March 3, 2015, and authorized construction in the vicinity of Indian Point on Sept. 24, 2015.

 

 

 

 

 

 

NRC Inspectors Head to Indian Point 3’s Electrical Supply Room

Neil Sheehan
Public Affairs Officer
Region I

Dousing the fire that ensued after one of the Indian Point 3 nuclear power plant’s main transformers failed on the evening of May 9th required substantial amounts of water, as well as foam. The water was applied by the automatic fire-suppression system for the transformer and by the on-site fire brigade and firefighters from off-site who provided assistance.

indianpointOne of the follow-up concerns for the NRC is that during the event, some water was found on the floor of an enclosed room inside the plant housing electrical supply equipment. The power that flows through that equipment is used to operate plant safety systems and components.

The equipment was not affected by the water during the May 9th event, and the plant was safely shut down. The plant remains out of service while work to install a replacement transformer is carried out.

In order to better understand what occurred, the NRC is launching a Special Inspection at the plant today. The three-member team will evaluate, among other things, how the water – apparently totaling an inch or two on the room’s floor — ended up in the room; and the potential for a significantly larger volume of water to build up and adversely impact the electrical equipment.

The NRC applies risks insights and specific knowledge of plants when determining whether to perform a follow-up inspection and what type. In this case, the NRC decided it was appropriate to conduct a Special Inspection, the first level of “reactive” reviews performed in response to an event. The agency performs such inspections to independently evaluate and assess what occurred during an event, as well as any plans by the plant’s owner to fix related problems.

In addition to the Special Inspection, the NRC is continuing to review the transformer failure, operator and equipment response during the event, and other issues.

A report containing the findings of the Special Inspection will be issued within 45 days after the formal conclusion of the review.

Indian Point’s Timely Renewal: The Background

Diane Screnci
Senior Public Affairs Officer
Region I
 

On Sept. 29, 2013, Indian Point 2 will enter what’s called the period of “timely renewal,” while the NRC continues its consideration of Entergy’s application to renew the unit’s operating license.

inptThe NRC’s timely renewal regulation implements a provision of the Administrative Procedure Act passed by Congress. Under that regulation, if a licensee requests a renewed license at least five years before expiration of its current license, the request is considered “timely” and the facility is allowed to continue to operate under its existing license until the NRC completes its review and reaches a decision on the license renewal request.

During the period of timely renewal, Entergy will have to continue to meet all of the regulations and license conditions that currently apply. In addition, in a May 1 letter to the NRC, Entergy voluntarily committed to update its Final Safety Analysis Report to include the aging management programs, and to implement the commitments it has made, for a renewed license. Indian Point 2 will continue to operate under its current license with these modifications, to assure continued safe operation during the timely renewal period, until the NRC reaches a decision on whether to approve the license renewal application.

Entergy submitted a license renewal application for Indian Point 2 and 3 in April 2007. The current operating license for Indian Point 2 expires at midnight September 28th; Unit 3’s license expires two years later, in December 2015.

Typically, the NRC staff takes about 18 to 24 months to review a reactor license renewal application. If there’s a hearing on the application, the process may take about 30 months to complete. In the Indian Point case, the hearing has taken longer than projected, in part due to the large number of contentions the parties have raised in the proceeding.

In addition, a decision on the Indian Point license renewal application has been deferred pending further Commission action involving the Waste Confidence Decision. In its Waste Confidence Decision and Temporary Storage Rule, updated in 2010, the Commission made a generic determination that spent nuclear fuel can be stored safely and without significant environmental impacts for a certain period of time after a nuclear plant permanently shuts down. In June of last year, the D.C. Circuit Court of Appeals found that some aspects of the 2010 Waste Confidence rule update did not satisfy the NRC’s obligations under the National Environmental Policy Act and vacated that rule. In response, the Commission decided to defer all final licensing decisions that rely on the Waste Confidence Decision while it takes steps to address the court’s decision. This applies to various license applications, including the Indian Point 2 license renewal application.

The NRC will continue to provide oversight of activities at both Indian Point 2 and 3 during the period of timely renewal. Last year, we conducted 11,000 hours of inspection at the two units. We’ll devote a similar number of inspection hours this year. Some of that includes inspection of the licensee’s commitments and aging management programs related to license renewal.

In short, even though a final decision hasn’t been reached on the renewal of the Indian Point 2 license, NRC will continue to assure that it operates safely during the period of timely renewal.