Dry Cask Storage Act of 2018 This bill amends the Nuclear Waste Policy Act of 1982 to require each licensee of the Nuclear Regulatory Commission (NRC) to submit a plan for: (1) transfer (including on-going additional transfers) to spent nuclear fuel dry casks of any spent nuclear fuel stored by the licensee for at least seven years in spent nuclear fuel pools, and (2) configuration of the remaining spent nuclear fuel in the pool in a manner that minimizes the chance of a fire if there is a loss of water in the pool. The NRC must approve or disapprove the plan within 90 days after its submission. The NRC may provide grants to any licensee with an approved plan to assist in the cost of transferring spent nuclear fuel to dry casks under the plan. The bill requires the emergency planning zone applicable to each civilian nuclear power reactor to be at least 10 miles in radius until all spent nuclear fuel at the reactor has been transferred to dry casks. The NRC must expand to 50 miles in radius the emergency planning zone applicable to each reactor not in compliance with an approved plan. The licensee is responsible for all costs associated with the expansion. The Department of the Treasury must transfer annually to the NRC, to pay the costs of the grants program, 10% of the interest generated during the preceding fiscal year from investments of the Nuclear Waste Fund.