Commercial sector

Since over 80% of the commercial nuclear reactors under consideration for this paper are in the USA, the following discussion focuses on the expense and schedule of the decommissioning task only in the USA.

As of late 2001, 14 power reactors in the USA had undergone decommissioning using Safestor, and 6 have utilized Decon. A total of 27 US

MAGNITUDE OF THE DECOMMISSIONING TASK 57

commercial reactors have been shut down and are in some stage of decommissioning.

The cost of decommissioning commercial power reactors in the USA has recently been estimated to be approximately $325 million per reactor [6]. This translates to a decommissioning task in Canada, Mexico and the USA of more than $50 billion. This number is a rough approximation, given the wide range of decommissioning options (i.e. Decon, Safstor, Entomb and multiple combinations), schedule and complexity (e.g. size and type of reactor, degree of contamination, volume and type of waste requiring disposal, and time period for decommissioning). A major factor in costs is the end state to be achieved for the site. For example, cleanup of a reactor site to an unrestricted usage or

‘green field’ condition is more expensive than a site planned for restricted usage (i.e. ‘brown field’).

Following reactor shutdown, the spent nuclear fuel is removed from the reactor core and stored in the spent fuel pool. Next, the fuel rods are moved to interim storage such as dry cask storage on or near the site. The third phase entails a waiting period for reduction of residual radioactivity through naturally occurring decay of the isotopes. For example, in the three years between closure and the onset of dismantling, the reactor core for the Shippingport PWR had decreased from an initial radioactivity level of 30 000 Ci to 16 000 Ci [7].¹ Built in 1957, Shippingport was the first large scale nuclear power reactor in the world. Another ‘first’ was that the DOE completed decontamination and decommissioning of the reactor in 1990, the first such cleanup of a power producing nuclear reactor in the USA. Finally, dismantlement or entombment takes place.

The 104 commercial power generating reactors in the USA have operating licences that expire between 2009 and 2036 [1]. Some of them may be able to have their operating licences extended following rigorous safety and operational inspections. However, as of this writing, 50 reactors are scheduled to shut down prior to 2020, an additional 47 before 2030 and the remaining 7 by 2036. This represents a virtual ‘bow wave’ of decommissioning activity and costs in the USA starting in the next seven years. Commercial power reactors in the USA operate under Federal regulations and statutes that require a percentage of the money charged for electricity to be accumulated in a fund for decommissioning. However, a 1997 study [8] indicated that as many as 40 nuclear power plants are likely to close by 2005 for economic reasons. Not only will this have a negative impact on the domestic power supply, but early closure

BUBAR and CLARK

58

11 curie (Ci) = 3.70 × 10¹⁰Bq.

will also result in insufficient funds being accumulated for decommissioning.

This liability must be addressed early on.

In addition to the power reactors, there are 36 non-power reactors (i.e.

research and medical isotope reactors) operating in the US commercial sector.

There are 15 more that are under decommissioning orders or are otherwise not permitted to operate. Although these types of reactors are generally smaller than power generating reactors, their decommissioning costs will certainly total in the hundreds of millions of dollars.

2.2. USDOE

The DOE was responsible for decommissioning 24 uranium milling operations located in 10 States. These facilities were operated by private companies to process uranium ore for the US Atomic Energy Commission (later DOE). Once the plants were shut down, the remaining tailings piles represented the potential for long term health issues caused by low level radioactivity and various hazardous substances associated with ore processing.

The radioactive and hazardous components were spread through the wind and water, resulting in contamination of soil, groundwater and surface water.

Several instances of contaminated drinking water wells were also found. It has been estimated that 96% of the contaminated waste (by volume) for which the DOE is responsible is the result of uranium mill tailings.

Additionally, more than 5000 “vicinity properties” required deconta-mination and/or decommissioning. Vicinity properties are areas outside the original mill site that were contaminated through the wind and water as well as by human activities. For example, in the area surrounding Grand Junction, Colorado, the mill tailings were considered to be an excellent source of aggregate material used in construction projects. As such, a large number of foundations and backfill areas in, around and beneath public and private buildings were found to be contaminated with low levels of uranium. Direct gamma radiation from the decay of uranium can result in significant health issues. Additionally, one of the most significant health issues resulting from uranium contamination is that one of the natural decay products, radon gas, can accumulate within buildings. The US Environmental Protection Agency (EPA) has noted a strong correlation between high levels of radon gas in buildings and various health problems, including increased occurrences of lung cancer.

All of the 24 ore processing sites have been decommissioned, with the tailings excavated and removed to engineered disposal facilities or capped in place. Decontamination and remediation of the vicinity properties has also been completed. The total cost for this work was nearly $1.5 billion [9]. The disposal sites are now under long term stewardship, including institutional

MAGNITUDE OF THE DECOMMISSIONING TASK 59

controls and monitoring as required under US Nuclear Regulatory Commission (NRC) licences. Estimates of all decommissioning and cleanup costs of uranium producing projects in the USA total nearly $2.5 billion [9].

Additionally, groundwater restoration projects will continue for a number of years at many of these sites.

As indicated at the beginning of this paper, the latest estimate for life cycle costs of the DOE’s Office of Environmental Management is at least

$220 billion and potentially greater than $300 billion [4]. This does not include the costs associated with DOE operating facilities not currently within the EM programme. At the end of Fiscal Year (FY) 2001, the DOE estimated its environmental liability for active facilities [10]. By definition, this estimate did not include those facilities covered in the EM life cycle cost estimate, nor did it account for facilities considered elsewhere by the programmes or sites responsible for managing them. The estimate for “the future costs of stabilizing, deactivating, and decommissioning contaminated active facilities” is approximately $19 billion [10]. As can be seen by these estimates, the costs for the DOE facilities managed by the EM programme represent the lion’s share of decommissioning costs.

One of the major decisions facing the DOE, its regulators and its stakeholders is ‘How clean is clean’? That is, do all sites have to be cleaned up to the same standards (i.e. green field or unrestricted use), or can some sites planned for restricted use such as reindustrialization be cleaned up to lesser (i.e. brown field) standards? These decisions must be made very early on in the planning process associated with decommissioning and cleaning up a site.

The amount of waste generated from various decommissioning strategies [3] will be vastly different. For example, a site that will be under long term institutional controls restricting site access could be expected to generate about 1 million m³of waste during decommissioning. The same site, if slated for brown field ‘mixed land use’ (e.g. industry) may generate about 35 million m³ of waste during cleanup. If the green field unrestricted land use approach is adopted (i.e. residential/agricultural), the waste volume would be expected to nearly triple to about 100 million m³[3]. The amount of time, work and expense associated with cleanup to various land use standards also rises in a similar pattern.

There must be a balance between the costs involved with cleaning up a site and the amount and quality of land use needed/wanted. Transportation and disposal costs for the wastes rise every year. Additionally, the ‘low hanging fruit’

(i.e. smaller and less technically complex) cleanup projects have already been completed by the DOE. Much improved technology and cleanup procedures are going to be needed in order to keep decommissioning costs from rising exponentially in the future. Equally important is adoption of a graded approach

BUBAR and CLARK

60

to cleanup whereby ‘how clean is clean’ is determined on a site by site basis.

These same decisions face the commercial sector as it tackles the bow wave of decommissioning that lies ahead.