On March 13, 2017, the UK’s first dry storage cask was placed inside Sizewell B’s Dry Fuel Storage Building at its designated location. The cask, known as HI-STORM MIC (the acronym MIC stands for Mega-Impact Capable), designed by Holtec in close cooperation with EDF Energy for a 100-year design life, was manufactured at Holtec’s Pittsburgh, PA plant. Not only is HI-STORM MIC a first for the UK, it also embodies many firsts in the realm of engineered safety for the global dry storage industry. Some examples of groundbreaking innovations built into the Sizewell’s HI-STORM overpack:
- The Sizewell B cask employs a double wall canister providing an incomparably-increased level of radionuclide confinement protection (compared to the single wall design that is the configuration commonly used around the world).
- Setting down a whole new plateau of safety, each HI-STORM overpack is equipped with its very own impact limiter designed to protect the loaded canister during its lowering in the cask’s cavity in the highly-unlikely scenario wherein both independently operating load handling devices in the single failure proof lifting equipment are assumed to fail simultaneously.
- The exterior shell of each canister is eddy current tested to serve as a reference for future aging management surveillances (a valuable innovation for the industry concerned with long term monitoring of canister integrity).
- The amount of and placement of shielding in the cask provides orders of magnitude greater dose blockage than the standard cask design reducing the radiation escaping to the environment to a tiny fraction of the cosmic radiation around us.
Fittingly, this most advanced ventilated storage cask was developed by Holtec in collaboration with the UK’s sole nuclear generator (EDF Energy) under the aegis of the Office for Nuclear Regulation (the UK’s independent nuclear safety regulator) known for its tough regulatory regime. We think the technology trailblazed by the Sizewell B HI-STORM will serve EDF Energy well across its far-flung nuclear operations, especially in the upcoming nuclear projects in the UK.
While the HI-STORM casks are designed for open-air storage, EDF Energy decided to build a structurally competent enclosure building to house them as well as all required ancillaries to ensure an enhanced service life. The photo below shows EDF and Holtec executives standing in front of the HI-TRAC transfer cask in the Spring of 2016 when the facility was inaugurated and pre-commissioning tests began.
Six more HI-STORMs will be loaded in the ongoing campaign being executed by a team of Holtec Britain Limited’s Business Unit and EDF Energy personnel which has functioned in a spirit of exemplary cooperation and solidarity. To quote EDF Energy Generation’s Managing Director, Mr. Stuart Crooks, “The Sizewell B dry store is a first of a kind for the UK. We have taken an already robust solution from Holtec and worked in strong collaboration to further improve the design resulting in industry-leading safety and security for the 100-year design life. The project was delivered on time thanks to strong trust, transparency and teamwork between EDF Energy and Holtec working together, removing silos and ensuring a one team, one project approach. This is a proud moment for all involved.”
In a joint statement, Kris Singh and Stuart Crooks state, “We salute the dedication and commitment of EDF Energy’s people led by Jerry Haller and Holtec’s personnel led by Tom Marcille, who together provided the coherent project leadership that has made this outstanding success possible.”