WNN Daily World Nuclear News November 11, 2020

  11 November 2020

REGULATION & SAFETY: Local consent clears way for restart of Onagawa 2

Tohoku Electric Power Company today received approval from Murai Yoshihiro, the governor of Miyagi Prefecture, to restart unit 2 of its Onagawa nuclear plant in the northeastern Japan prefecture. The utility aims to restart the 796 MWe boiling water reactor (BWR) in fiscal 2022 at the earliest. Murai announced his decision after meeting with Hiroshi Kameyama, mayor of the city of Ishinomaki, and Yoshiaki Suda, mayor of the town of Onagawa. The two municipalities host the Onagawa nuclear plant. At a 9 November meeting, the leaders of most of Miyagi's 35 municipalities agreed to support the decisions of Onagawa and Ishinomaki. The prefectural council approved the restart in October. "I have decided to understand the government policy to promote the restart of nuclear power plants," Murai was quoted as saying by Nikkei news agency. "The operation is expected to create employment and have an economic spillover effect due to orders from local companies." The Onagawa plant was the closest nuclear power plant to the epicentre of the earthquake and tsunami of 11 March, 2011, but sustained far less damage than expected. The earthquake knocked out four of the plant's five external power lines, but the remaining line provided sufficient power for its three BWRs to be brought to cold shutdown. Onagawa 1 briefly suffered a fire in the non-nuclear turbine building. The plant was largely unaffected by the tsunami as it sits on an elevated embankment more than 14m above sea level, but the basement floors of unit 2 were flooded. A mission from the International Atomic Energy Agency in August 2012 concluded that the structural elements of the nuclear power station were "remarkably undamaged, given the magnitude of ground motion experienced and the duration and size of this great earthquake". Tohoku applied to the Nuclear Regulation Authority (NRA) in December 2013 for a safety assessment of Onagawa 2 to verify countermeasures applied at the plant meet new safety standards. In late November 2019, the NRA approved a draft screening document that concluded the upgraded plant will meet revised safety standards, introduced in January 2013. On 26 February this year, the NRA approved the final screening report, clearing the way for the unit to resume operation. The utility is still required to complete the countermeasure upgrades before it will be able to restart Onagawa 2. Tohoku expects to spend about JPY340 billion (USD3.2 billion) on the countermeasures, which include seismic reinforcement of Onagawa 2 and construction of a 29-metre high and 800m long sea wall to protect the plant from tsunamis. It had originally planned to complete this construction work by April 2017, but the schedule has been pushed back a number of times. It now expects this work to be completed in FY2022 (ending March 2023). Onagawa 2 will become the first Japanese BWR - the same type as used at the damaged Fukushima Daiichi plant - to be restarted. BWRs at Tokyo Electric Power Company's Kashiwazaki-Kariwa plant in Niigata Prefecture and unit 2 of Japan Atomic Power Company's Tokai plant in Ibaraki Prefecture have already received NRA approval to restart, but have yet to obtain local consent. Tohoku has already decided to decommission Onagawa unit 1 and is considering applying to restart unit 3.

NEW NUCLEAR: Rosatom delivers RPV to Akkuyu plant site

The reactor pressure vessel (RPV) for unit 1 of the Akkuyu nuclear power plant in Turkey was delivered to the site yesterday, Rosatom has announced. The equipment was transported 3000 km over 20 days from the Atommash quay at the Tsimlyanskoye reservoir in Volgodonsk, Russia to the Eastern Cargo Terminal at the Akkuyu plant site, which is in Mersin province. Atommash is a subsidiary of Russia's AEM Technology. The RPV weighs 330 tonnes, has a 4.5 m diameter and is 12 m high. Its manufacture took nearly three years and involved more than 750 production processes. It passed more than 300 quality control tests at various stages of its manufacture. "Construction and installation works at the Akkuyu site are progressing at a very good pace," Sergey Butckikh, first deputy CEO and director of NPP construction at at Akkuyu Nükleer AŞ, said. Arrival of the RPV follows delivery in late September of four steam generators for the unit. The 4800 MWe plant will comprise four VVER1200 reactors and is expected to meet about 10% of Turkey's electricity needs. Turkey aims to bring unit 1 online in 2023, the centenary of its foundation as a republic.

NEW NUCLEAR: NuScale announces SMR power uprate

NuScale Power has announced a 25% increase in power output for its NuScale Power Module small modular reactor, which it says will lead to significant cost savings. It has also announced options for smaller four-module and six-module plant sizes in addition to its flagship 12-module plant. The NuScale Power Module is a pressurised water reactor with all the components for steam generation and heat exchange incorporated into a single integrated unit. The company said yesterday that, following value engineering efforts using advanced testing and modelling tools, it has now concluded that the unit can generate 77 MWe (gross) per module, or about 924 MWe for a 12-module power plant. The increased power output comes without any major changes to the NPM technology. The increase in generating capacity lowers the overnight capital cost of a 12-module facility from an expected USD3600 per kilowatt to about USD2850, the company said. "Furthermore, the scalable, 12-module power plant will now approach a size that makes it a true competitor for the gigawatt-size market," it added. The smaller four and six-module power plant solutions will give customers more options in terms of size, power output, operational flexibility and cost, NuScale said, with a smaller footprint and a focus on simplifying construction, reducing construction duration and lowering costs. "This new solution allows NuScale to support a larger cross-section of customer needs including power for small grids such as for island nations; remote off-grid communities; industrial and government facilities; and coal power replacements that require less power and help customers meet clean air mandates." The US Nuclear Regulatory Commission (NRC) in September issued a standard design approval for a 50 MWe-per-module version of NuScale's SMR, allowing that design to be referenced in applications for construction, operating and manufacturing licences and permits in the USA. NuScale had previously indicated plans to apply for standard design approval of a 60 MWe version, requiring additional NRC review. It has now said the power uprate will be reviewed by the NRC as part of that application, which it expects to submit in 2022.

NEW NUCLEAR: Detailed testing of IMSR fuel salt starts

Terrestrial Energy and the US Department of Energy's Argonne National Laboratory (ANL) have begun detailed testing of the fuel salt for Terrestrial's Integral Molten Salt Reactor (IMSR). The IMSR uses two molten salt streams - a fuel salt that contains the uranium and another salt to transfer heat from the reactor to the electricity generation system. ANL will use an extensive array of characterisation techniques and advanced laboratory equipment to determine thermo-physical properties of the IMSR fuel salt to regulatory standards. ANL will prepare and test fuel salt mixtures that replicate the fuel salt composition over the full IMSR operating cycle. The laboratory investigations will include melting point determinations, density, viscosity, heat capacity and thermal diffusivity measurements. Terrestrial said this fuel salt testing programme is part of a broader ongoing confirmatory testing programme for fuel, components and systems used in the IMSR power plant. It said the results of these tests will support licensing applications as first commercial deployment of the IMSR power plants advance. Terrestrial began working with ANL in 2016 after receiving an award from the US Department of Energy's Gateway for Accelerated Innovation in Nuclear (GAIN) programme, which directs support to the nuclear community commercialising innovative nuclear technologies. "Our first GAIN award catalysed what is now a full-scope commercial engagement with the lab," said Simon Irish, CEO of Terrestrial Energy USA. "Our strategy is to continue working with world-class laboratories offering expertise in relevant areas, rather than building that testing capability in-house. This strategy keeps our engineering resources focused on the IMSR power plant, rather than developing lab-based R&D capabilities, and is essential to meet our early deployment schedule." Molten salt reactors use fuel dissolved in a molten fluoride or chloride salt, which functions as both the fuel (producing the heat) and the coolant (transporting the heat away, and ultimately to, the electricity generating equipment). Terrestrial's IMSR builds on 50 years of experience at the USA's Oak Ridge National Laboratory, and integrates the primary reactor components, including the graphite moderator, into a sealed and replaceable reactor core unit with an operating lifetime of seven years.

NEW NUCLEAR: Rosatom plans first land-based SMR for Russian Far East

Rosatom plans to build a nuclear power plant equipped with an RITM-200 small modular reactor in the village of Ust-Kuyga, in Yakutia, which is in Far Eastern Russia. The land-based small nuclear plant will be able to supply electricity to isolated power systems or remote areas and consumers. The latest RITM-200 design is the result of 400 reactor-years’ worth of combined experience operating small reactors on ships in Russia’s fleet of nuclear-powered icebreakers, Rosatom said. To date, six reactors of the RITM series have already been manufactured and installed on three new universal icebreakers. The lead icebreaker, Arktika, completed trial operations on 21 October. "Over the course of pre-design fieldwork, Rosatom specialists carried out various engineering surveys to evaluate the suitability of the chosen site, including a hydrometeorological survey, an environmental survey, a geodetic survey, and a geological survey, amongst others," Rosatom said. "In particular, these surveys included soil and core sampling by drilling wells, water sampling, reconnaissance studies, and the creation of a reference geodetic network, amongst others. Subsequent steps include the laboratory evaluation of collected samples, the preparation of a final report on the results of pre-design surveys for the selection of a construction location." The LK-60 icebreakers Arktika, Sibir and Ural are dual-draught (8.55 or 10.5m) wide-beam (34m) ships of 25,450 dwt or 33,540 dwt with ballast, able to handle 3m of ice. They each have two RITM-200 reactors of 175 MWt each, delivering 60 MWe at the propellers via twin turbine-generators and three motors. Arktika enters operation this year, Sibir in 2021 and Ural in 2022.

REGULATION & SAFETY: Modernised safety management rule streamlines processes

A modernised nuclear safety management rule due to come into effect in the USA focuses on safety while minimising unnecessary administrative burden. The Final Rule focuses on improved clarity of requirements and will allow more attention to be paid to safety hazard challenges and less time on redundant efforts or administrative tasks, according to Garrett Smith, director of the Office of Nuclear Safety at the US Department of Energy (DOE). The DOE's overarching nuclear safety requirements are governed by rule 10 CFR part 830, Nuclear Safety Management, first published in 2001. This governs the conduct of DOE personnel and contractors who carry out activities that affect, or may affect, the safety of DOE nuclear facilities. However, since the rule was published, the department and its contract workers "adhered to what are sometimes duplicative and unnecessary administrative tasks that do little to enhance safety", Smith said in an article published by the Office of Nuclear Safety. The DOE in 2017 began work to modernise and update those requirements to increase efficiency and effectiveness without "sacrificing" safety, in an effort undertaken as part of the US Administration's broader regulatory reform agenda. A working group led by the DOE Office of Nuclear Safety initiated the effort to pursue a rulemaking based on a list of proposed internal reforms recommended by then-Deputy Energy Secretary Dan Brouillette, with the intent of achieving significant improvements in efficiency while also maintaining contractor performance standards. The working group also incorporated input from nuclear safety subject matter experts from the DOE's National Nuclear Security Administration, Office of Environmental Management, Office of Nuclear Energy, and Office of Science. A Notice of Proposed Rulemaking containing proposed changes was issued for public comment by the DOE in August 2018 and, following a "thorough, transparent, and deliberative process" including four public meetings, a final rulemaking decision was issued in October 2020. "The final rule, which incorporates nearly 20 years of contractor operational experience and public feedback, focuses on improved clarity of requirements and modest process changes that reduce unnecessary burden to make DOE nuclear safety management operations more efficient. This allows DOE to pay more attention to higher hazard safety challenges and less time on redundant efforts or administrative tasks," Smith said. Specific enhancements to 10 CFR part 830 include: streamlining the process by which newly identified safety concerns, referred to as unreviewed safety questions, are defined; elimination of duplicative DOE approvals of safety documentation; modification and clarification of definitions of new and existing nuclear facilities; and updates for added clarity, including references to DOE guidance and policy. The Final Rule will be effective from 18 November, Smith said.

11 November 2020