This memo discusses the effects of advancing to higher power levels of the 105 Piles (D-Pile). It is concluded that there is no technical reason against a cautious advance to higher powers; the units can be run at higher levels than their rating of 250 MW, or the additional reactivity that they will gain with time may be taken entirely in the form of lower peak temperatures and radiation levels. The decision as to what course to follow between these extremes involves such issues as the best use of uranium and the most effective separation of adequate amounts of product of proper quality.