T₀ = 15 °C · Tk = 800 °C (core only) · Tc = 15 °C. He coolant at 750 °C outlet · TRISO pebble fuel · two modules per turbine. SG He→steam (20.6 %) modelled as internal exchanger without Tk annotation — core + SG = 64.1 % of total irreversibilities. T1: 3.5 % · T2: 3.4 % · T3: 3.2 % · T4: 3.0 % · T5: 3.0 % · T6: 2.8 %. Full balance: s4e2.com/exerg/HTR-PM-nominal_EB.pdf