Approval granted for decommissioning of Grohnde

14 December 2023

Lower Saxony’s Ministry for the Environment, Energy & Climate has granted approval to PreussenElektra to begin dismantling the 1360 MWe pressurised water reactor at Grohnde NPP (KWG) in Germany, which was closed down in December 2021. “We are implementing the nuclear phase-out decided 12 years ago and ensuring maximum safety for dismantling,” said Environment Minister Christian Meyer.

Grohnde was closed in line with Germany’s decision to phase out nuclear power, taken in the wake of the 2011 Fukushima accident in Japan. Eight nuclear units were permanently shut down in 2012. These included EnBW's Phillipsburg unit 1 and Neckarwestheim unit1; E.ON's Isar unit 1 and Unterweser; RWE's Biblis A&B and Vattenfall's Brunsbüttel and Krümmel (both already closed). The remaining nine reactors were to close by the end of 2022. E.ON’s Grafenrheinfeld closed in 2015; RWE’s Grundremmingen B in 2017; EnBW’s Phillippsburg unit 2 in 2019; Vattenfall’s Brokdorf, E.ON’s Grohnde and RWE’s Gundremmingen C in 2021; and E.ON’s Isar 2, EnBW’s Neckarwestheim 2 and RWE’s Emsland in April 2023. Two older reactors - E.ON’s Stade NPP and ENBW’s Obrigheim had already been shut down in 2003 and 2005.

PreussenElektra, a subsidiary of E.ON, is responsible for decommissioning eight units - Würgassen (closed in 1994), Isar 1, Stade, Unterweser, Brokdorf, Grafenrheinfeld, Grohnde, and Isar 2 all now in various phases of decommissioning and dismantling.

With the KWG, all three PreussenElektra plants in Lower Saxony are now undergoing dismantling. The conventional demolition of power plant buildings has recently begun at the Stade and dismantling is advancing at Unterweser. “With the knowledge from these dismantling projects, we are well equipped and convinced that we can complete the dismantling of the KWG as planned by the beginning of 2037,” said PreussenElektra CEO Guido Knott.

Preussen Elektra applied for the first of two permits for the decommissioning and dismantling of Grohnde in 2017. After six years of testing, the Ministry of the Environment finally gave its approval. Plant manager Peter Schwarz is pleased that his team can now start the dismantling work. “In the past six years, many colleagues have worked hard to get the approval. It is good that we can get started now and put our planning preparatory work into practice.”

Meyer emphasised that the Grohnde plant will never go back into operation and will now be systematically dismantled. He ruled out any possibility of the plant ever being restarted. “With the dismantling and decontamination of the primary cooling circuit to protect the employees, decommissioning is practically and legally irrevocable. A return to nuclear power would be irresponsible and expensive.”

As to the next steps in dismantling, new logistics routes are being created within the control area and a residual material processing centre for the dismantled material is being set up in the reactor building. In addition, systems that are no longer required are being shut down and preparations are being made for dismantling of the internals in the reactor pressure vessel. At the same time, the remaining fuel elements in the wet storage facility are being transported to the approved interim storage facility used fuel at the plant site.

In the course of the dismantling KWG, around 15,000 tonnes of residues from the control area are expected to be generated, measured and cleaned with the aim of recycling them after an intensive examination and official confirmation.

Material that cannot be released - low and medium radioactive waste- will be separated, treated, packaged at an early stage and made available in the transport delivery hall, which still needs to be built on site. From there, they will be transport to the planned Konrad repository. PreussenElektra's goal is to dismantle its NPP fleet by 2040.

Meanwhile, German radioactive waste specialist GNS Gesellschaft fu¨r Nuklear-Service mbH said that the last of its CASTOR used fuel storage casks for a German NPP is expected to be delivered to Grohnde in 2025. In November, PreussenElektra ordered its last cask from GNS, which will be used at Grohnde.

To date, some 260 CASTOR casks, each weighing more than 100 tonnes, have been loaded and stored at the five PreussenElektra sites. By 2030, this should increase to 328. A total of more than 1600 CASTOR casks will eventually be in safe interim storage in Germany in on-site and centralised interim storage facilities, as well as in the interim storage facilities of research and federal institutions.

So far, more than 1400 CASTOR casks supplied by GNS have been loaded with used fuel and vitrified reprocessing waste from German NPPs and are stored in on-site and centralised interim storage facilities. The company expects to deliver around 150 more in the coming years.

"The last CASTOR order for a German nuclear power plant is definitely a significant milestone for us, but it does not mean the end of our cask business," said GNS CEO Daniel Oehr. "In the last seven years alone, GNS has received orders for more than 120 CASTOR casks from customers outside Germany. And we are working hard to win new customers from other countries. We already have long-term orders from foreign power plant operators, for example from Switzerland and Belgium.”

Image: Grohnde nuclear power plant (courtesy of PreussenElektra)

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