Visualisation of the NOL seen from the water

New Upgraded Warehouse (NOL) - The process behind Denmark's first of its kind

Join us behind the scenes as Per Søndergaard, Chief Consultant at Danish Decommissioning, explains the process behind Denmark's new upgraded storage facility for radioactive waste.

Onpaper, the task is actually relatively simple: build an upgraded storage facility.

But when the upgraded storage facility is to contain radioactive waste, the challenges begin to emerge.

Danish Decommissioning has been commissioned by a political decision to build a new upgraded storage facility, colloquially known as NOL, for Denmark's radioactive waste.

But what is the process behind such a storage facility, and what demands does it place on the finished building when what will be stored in it is radioactive waste?

These are some of the questions that Per Søndergaard, chief consultant at Danish Decommissioning, is working with on a daily basis in his role as project manager of the NOL project.

Why NOL?
Building the NOL stems from several challenges that the current warehouses at Danish Decommissioning are assessed to face.

First, in December 2013, Denmark was hit by storm Bodil, and the water level in Roskilde Fjord rose dramatically. At its highest, the water level measured 2.06 metres.
The water did not reach the radioactive waste, but the nuclear regulators decided after the storm to secure the waste against a water level of 3.06 metres in the future.

Secondly, there is the practical problem that Danish Decommissioning is running out of storage space over time, and thus needs additional capacity.

And thirdly, storing material in metal containers for long periods of time requires better moisture and climate control to prevent rusting or spoilage. For this, a relatively dense building is needed, for which it has been considered to improve the existing storage facilities.

Per Søndergaard explains the process that led to the NOL plans.

- Initially, improvements were made to the existing storage facilities at Danish Decommissioning, both in terms of capacity, storm surge protection and dehumidification. But this soon proved not to be an option, so it became clear that the only solution was to build a new upgraded storage facility

From thought to reality
The new upgraded storage facility will thus have to solve several challenges, but where do you start and how do you get started?

Per Søndergaard has the answer, because as he says.

- There's only one way to eat an elephant, and that's one bite at a time.

An approach that characterises the complex process that precedes the groundbreaking of the NOL.

This process is complex for several reasons, all of which stem from the waste to be stored in the warehouse.

Because one of the tenets of dealing with radioactivity is that you don't want to expose people to unnecessary risk of radiation, and that has a big effect on the process that will eventually lead to a finished 16-metre high building containing radioactive waste.

An additional challenge for the new upgraded storage facility is that the building needs security clearance. This approval requires, among other things, that the NOL be constructed in a way that protects both employees and other persons from radioactive radiation.

At the same time, it is required that the building requires as little maintenance as possible, in order to minimise the aforementioned risk of radiation.

Per Søndergaard says about this challenge:

- The fact that we are building a building that will require a minimum of maintenance over the next 50 years means that we have to choose materials and equipment that will require as little maintenance as possible. And that the building is constructed in such a way that maintenance and general operation are as low as possible.

This places demands on all design, on materials and on construction, all of which invariably have an effect on the economics of constructing such a building.

- There is a constant trade-off between dose attribution and establishment costs. We don't want a building that requires a major renovation during its lifetime, but on the contrary we want to build right from the start, says Per Søndergaard.

In addition, there are general rules that must be observed, including building regulations, local plans and environmental impact assessments.

Status today - security assessment takes time
The NOL process, at the time of writing, is where the safety assessment, which is crucial to breaking ground, is being worked on daily.

Here, one might be tempted to look abroad, but fundamentally each country has its own unique legislation and interpretation of this, in the area of radioactive waste and its storage.
However, this does not mean that Danish Decommissioning just sits with folded hands; on the contrary, with Per Søndergaard in the lead, work is being done on a daily basis to look at scenarios, materials and everything else related to the construction of the NOL.

A building that, like the way to eat an elephant, can only be built one way.

One part at a time.