This document contains the verification and validation (V & V) plan for analytical methods utilized in the nuclear design for normal and off-normal conditions within the Modular High-Temperature Gas-Cooled Reactor (MHTGR). Regulations, regulatory guides, and industry standards have been reviewed and the approach for V & V has been developed. MHTGR core physics methods are described and the status of previous V & V is summarized within this document. Additional work required to verify and validate these methods is identified. The additional validation work includes comparison of calculations with available experimental data, benchmark comparison of calculations with available experimental data, benchmark comparisons with other validated codes, results from a cooperative program now underway at the Arbeitsgemeinschaft Versuchs-Reaktor GmbH (AVR) facility in Germany, results from a planned series of experiments on the Compact Nuclear Power Source (CNPS) facility at Los Alamos, and detailed documentation of all V & V studies. In addition, information will be obtained from planned international cooperative agreements to provide supplemental data for V & V. The regulatory technology development plan will be revised to include these additional experiments. A work schedule and cost estimate for completing this plan is also provided. This work schedule indicates the timeframe in which major milestones must be performed in order to complete V & V tasks prior to the issuance of preliminary design approval from the NRC. The cost to complete V & V tasks for core physics computational methods is estimated to be $2.2M. 41 refs., 13 figs., 8 tabs.