On December 27, 2018, the U.S. Nuclear Regulatory Commission (NRC) announced that the agency plans to bring an enforcement action against Holtec International — the manufacturer of the steel and concrete casks used at the Vermont Yankee nuclear power plant to store spent fuel.

NRC officials held a pre-decisional enforcement conference with Holtec officials from 1:00 – 5:00 p.m. ET on January 9, 2019.  The conference, which was held in the Commission Hearing Room at NRC Headquarters, was open to the public and webcast.

For additional information on the webcast, please go to https://video.nrc.gov.

Background

The issue originated when a loose bolt was identified in the 18-foot tall casks at the San Onofre Nuclear Generating Station in California in March 2018.  Workers at the San Onofre Nuclear power plant discovered a loose four-inch stainless steel pin at the bottom of a canister as it was being prepared for loading with spent fuel.  The pin was part of a shim designed to support the fuel basket and allow airflow to the fuel assemblies within the canister.  As such, the shim is considered essential to the function of the fuel basket.  Regulators are concerned that the problem could affect the ability of the casks to effectively cool the nuclear fuel.

Since the Vermont Yankee plant shares a similar cask design as San Onofre, a two-month halt was initiated earlier this year when Entergy Nuclear Corporation was transferring the plant’s spent nuclear fuel to the air-cooled storage casks.  The transfer resumed in May 2018 and was completed this past summer.

During the two-month hiatus at Vermont Yankee, Entergy inspected the empty Holtec Hi-Storm 100 casks that Holtec had already provided for the fuel transfer and storage project and found no problems with the casks.  Entergy used a total of 58 casks, but it could not inspect the canisters already filled with fuel.  According to NRC, 31 of the 58 casks at the Vernon site were of the new Holtec design.

Transfer of the spent fuel was a key condition of the pending sale of Vermont Yankee by Entergy to NorthStar Holding Company.  The sale, which has received both state and federal approval, is expected to be completed early in the 2019 calendar year.

Overview

The action against Holtec International involves a new design that the company adopted for its casks before getting NRC approval.  The design has since been approved, according to an agency representative.

In particular, NRC asserts that Holtec changed the design of the Hi-Storm 100 casks — specifically the four-inch stainless steel pins that hold the basket, which in turn holds the spent fuel.  Holtec determined that it did not need to conduct a written evaluation, which was a violation of NRC safety regulations according to agency officials.  In the notice of violation from the NRC, the agency referred to “nonconforming and degraded conditions at both SONGS (San Onofre Generating Station) and VY [Vermont Yankee], respectively.”

NRC conducted an inspection at Holtec’s offices in Camden, New Jersey.  On November 29, 2018, NRC issued an inspection report identifying two apparent violations of the agency’s quality assurance regulations.  The NRC determined Holtec, when it changed the shim to the pin design in 2016, failed to establish adequate design control measures for selecting and applying materials, parts, equipment and processes essential to the function of safety-related structures, systems and components.  Holtec also failed to maintain written records of changes to its canister design, including an evaluation of why the design change could be implemented without applying to the NRC for an amendment to the canister’s Certificate of Compliance.

The NRC offered Holtec a choice between the pre-decisional enforcement conference or third-party mediation.  Holtec chose the conference, during which its officials will be able to present additional information for the NRC staff to consider in assessing the significance of the subject violations.  No final action will be taken at the conference on January 9, 2019.In addition to San Onofre and Vermont Yankee, the Holtec Hi-Storm 100 casks were also used to store spent fuel at nuclear plants including Dresden in Illinois; Grand Gulf in Mississippi; Hatch in Georgia; Columbia in Washington; Watts Bar in Tennessee; and, Callaway in Missouri.

For additional information, please contact David McIntyre of the NRC at (301) 415-8200.