A hydroprocessing reactor, an asset used in petroleum refining, is placed into service at a cost of $2.7 million. It is thought to have a useful life, with turnarounds and proper maintenance, of 18 years and will have a salvage value of nothing at that time.

a. What is the MACRS-GDS property class?

b. Determine the depreciation deduction and the unrecovered investment over the depreciable life of the reactor.