to the Ac_A and Gradient Grids of each of the Ion Sources via the (M/R), also located in the NBPC Building.. The The Tokamak Physk, _ (TPX) will utilize to the M/R employs a series High Voltage Switch Tube (high maximum extent theexisting Tokamak FusionTestReacta, r (TPTR) equipment and facilities. This is particularly trtte for powered Tetrode) in a floating deck design. Power the TFTR Neutral Beam (NB)system. Moat of the NB transmission from the M/R to the Ion Sources is hardware, plant facilities, auxiliary subsystems , power accomplished using a High Voltage Deck (HVD) and a systems, service infrutmctme, and oonlml |yl;telns fJtn be Transmission line from the HVD to the Ion Sources. used as b. The majar dumps in the NB hardwme are driven by Other power supplies include those for Arc, Filament the new operating duty cycle. The TFrR Neutral Beam wu and Decel Grid of each Ion Source. In the TFTR there are designed for opemimt of the Stoma= f_ 2 moonds every 150 twelve Ion Sources installed capable of delivering 34 MW t_cml. The TPX requires operation for 1000 secm_ every to the Ptamm. Itis _ tousethreeof theSourcesfor 4500 tagonds. During the Conceptual Design Phase of TPX TPX. The Electrical Power System will be reconfigured every cempcmemof the TFFR Nil _ Power System was and modified to feed the three Ion Sources to meet the TPX ! analyzed to verify whether the equii3meettctm meet the new operational req_mts with or without modifications. The operating scenarios. Pow_ System oonvem 13.8 kV prime power to controlled power requiredat the NB smax:es.The majorequipment DESCRIPTION AND CHANGES involved are circuit breakers, auto and rectifier _ansformen, surge suppreuion comimtmnt _ power W.a'ggle,, HV Decks, and The majority of the NB power components are usable HVDC power transmission to murces. Thermal models were for TPX with appropriate modifications and reconfi_n developed for the power transformen _ simulate the new to achieve the the,mini capability required for long pulse operational requirements. Heat rum wea'e conducted for the operation. Each component of the Electrical Power System power tetrodes to verify capability. Other oomponems were was analyzed to verify whether the new operational analyzed to verify their thermal limitations. This paper requirements can be met. The One Line diagram of the describes the details of the evaluation and redesign of the Accei Power System is shown in Fig. 1. The principal electrical power Iystem components to meet the TPX operational requiremems. COOC_ was the thermal capability of the Autotransfonner and the Rectifier Transformer. Thermal models for the