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Feasibility Analysis

by Matthew Formby

This economic feasibility for the submarine nuclear power plant, primarily developed by Amanda Gallo's work, has three parts. 

First is a consideration of the comparable costs of a land based nuclear power plant. This includes the cost of loans, necessary specialists, maintenance, fuel, and more. It also assumes, for purposes of staffing and related costs, that a typical plant has one reactor (as most current nuclear power plants do), and a capacity of 971 MWe. Click to view the feasibility estimate for a typical nuclear power plant.

The second analysis is for our submarine nuclear power plant, which should be viewed in comparison to the first analysis. This analysis assumes similar costs to a land-based reactor, but with added costs for the facility itself (based on the cost of a naval nuclear submarine), to address the unique costs of a submarine power plant. For cost, utilization, and capacity this estimate tries to match the typical nuclear power plant, and assumes only established and well known reactor technology. Click to view the submarine nuclear power plant economic feasibility.

Finally, to take into account newer, and potentially safer reactor technology, this third feasibility considers the possibility of using a reactor similar to that designed by Transatomic Power. It makes a cost estimate in the same way as the second analysis, but uses the estimated cost of a TAP reactor plus 550 million to estimate complications for mobile underwater power plant. Click to view the submarine nuclear power plant using a TAP reactor.

The notes below explain specific decisions made for the various feasibility studies.

Offshore Submarine Nuclear Power Plant: Capital Investment Cost of $6,000,000,000

Total cost estimate to build the underwater nuclear power plant, including nuclear fuel ranged from $1.5 Billion to $2.5 Billion for each power plant. This estimate is between $250 Million to $1.25 Billion over the cost of a typical land based nuclear reactor with the same reactor output (250 MWe). These costs are based on naval warships (including weapons costs that wouldn't be carried over). For this reason estimations start at $1.5 Billion dollars for the entire station, but it is important to take these higher costs into account.

Cost Per Kilowatt

Average cost for a nuclear power station is around $5,000 per kilowatt of capacity. The total capital investment for any given power plant can range for a number of reasons, but for the typical land based power plant this cost is a reasonable estimate. Atypical aspects used in the underwater application are added in or separately calculated.

Utilization: 70%

This refers to how much of the power generated is actually used by the grid, and is affected by a number of factors. The estimate is from a nuclear engineer, naval officer, and RPI graduate.

Station 60 year fuel life

Within the economic feasibility, it's uncertain how long each reactor would last (specifically in comparison to the life of the ship/housing). A 60 year operating life isn't certain for either a typical nuclear power plant or the submarine nuclear power plant; but was selected as reasonable for comparison between the two. Operating lifetime is uncertain and based on licensing, standard of maintenance, and the owning company. After all of this, 4 years of lost revenue time (during maintenance) is considered.

Submarine Nuclear: Undersea Dock and Connections Costing $40,060,000

Cost of dock and cables estimated from past social engineering projects that have called for underwater power cables for grid connection. Estimate calls for approximately 1 mile of cable. But costs vary widely; as these cables are often custom built per structure. Because of the nature of this cost, it is likely to be less if production is established. (Editor added or modified. Cost was unknown before)

Submarine Nuclear: Crew (quantity)

Crew of 60 could be significantly reduced depending on systems used. For example; one could eliminate the need for internal ship gyro and navigation crew if externally tugged out, ballasted and connected to the dock.

Submarine Nuclear: Drydock / port 'Overhaul'

Regular PMS as well as biennial inspections by the NRC can be conducted underway. This can also take between 1 and 1.5 years; accounted for in loss in revenue. Rough estimate of overhaul costs refer to Table 5 (Page 13) of 'Overhaul Costs in Public and Private Shipyards: A Case Study'.

Submarine: Drydock Frequency

Subs go into dock at most frequently every 5 years for its 25 year lifespan, but will the life of the boat be extended, considering it won't be in full operation as militarized subs are?

Overhaul, averaging $600,000 is expected to be needed once every 8 years, but given the uncertainty of a 50 to 60 year lifetime, and loss in revenue due to maintenance, a rate of twice this value is also estimated.

Submarine Nuclear: 250 MWe Reactor

The combined cost and capacity of four 250 MWe offshore nuclear power plants was used to compare to a single 1 GWe land based power plant meeting the same demand. The decision to use 250 MWe reactors is based on the similar proposal (though for towed, rather than self-driven underwater power stations) FlexBlue by the DCNS Group. Higher capacity rectors per structure are more cost-efficient.

(Editor Addition / Adjustment) 

Added consideration of reactor (and cited cost comparison) of Trans Atomic Power's fast reactor, which has a 520 MWe design. Trans Atomics 520 MWe land reactor is estimated to cost $1.7 Billion, an additional $550 million (greater than the added cost in the second analysis) was added for underwater 'complications.' Size and safety considerations for this reactor in the project are made in the submarine nuclear power article.

Land Based 971 MWe rector

Used median reactor capacity in the U.S. (mean is 894, but disproportionately affected by outliers). Most nuclear power plants in the U.S. use a single reactor, which was again used for a typical land-based nuclear power plant model.