November 5, 2020

The proposed entombment at Rolphton, Ontario

Source document: Draft Environmental Impact Statement for the Nuclear Power Demonstration Closure Project

Here is a quote from the document: (emphases in red text added)

Normal Evolution Scenario

In this scenario, the facility is assumed to be closed as planned, with no unforeseen events. Parts of the NPDWF that lie below the water table will gradually resaturate. It is expected that resaturation may take several decades to complete. Once saturated, the soluble contaminants in the facility will begin to be released into the groundwater… The primary point of potential contaminant release into the biosphere is taken to be the riverbed close to the shore of the Ottawa River (pages 9-6 and 9-7)

·        Concrete/grout/cement:It is assumed that the grout will gradually degrade as the cement constituents are slowly leached out upon contact with groundwater… (page 2-24)

·        The cap: It is assumed that the cap starts to degrade 100 years after its emplacement and is assumed to have fully degraded (in terms of hydraulic performance) by 1,000 years after decommissioning is complete…. (page 2-24)

This is table 4.4-1 showing a partial inventory of the radioactive contaminants contained in the old NPD reactor, that will migrate into the Ottawa River in the “Normal Evolution Scenario”:

The proposed entombment at Pinawa, Manitoba

Source document: Draft Environmental Impact Statement for the In Situ Decommissioning of the Whiteshell Reactor #1 Project

Here is a quote from the document: (emphases added)

Following the encapsulation of WR-1 and the cessation of pumping from the sumps, the groundwater elevation will be restored to an equilibrium elevation and the majority of the grout (including the remaining components of the reactor) will be situated below the groundwater table... The assumption is that these materials will experience an increase in hydraulic conductivity as they degrade over time.  Simulations were completed to estimate the groundwater flow through the components of the decommissioned structure and results of these simulations were used as input to the analytical solute transport model.

The solute transport model was defined as a source area (representing the remaining solute mass contained within the decommissioned structure), a barrier for containment (the building foundation), a transport pathway (the bedrock, which receives flow from the decommissioned building via advection and diffusion through the barrier and into the surrounding fill material), and a receptor (the Winnipeg River).  (page 6-148)

The cover, grout, and foundation were assumed to degrade at rates comparable to other projects (i.e., Savannah River), which increased groundwater flow through time, resulting in total failure (degradation) of grout by year 10,000.  (page 6-202)

And here is Table 6.4.2-8 showing the radioactive materials that will migrate into the Winnipeg River after cessation of pumping and failure of the grout:

See also this post on the ways the the giant Chalk River Mound would leak radioactive contaminants into the Ottawa River: https://concernedcitizens.net/2020/11/04/the-proponents-own-study-shows-that-the-chalk-river-mound-will-disintegrate/