Feedheat-based electricity storage system for nuclear plant

An energy storage concept which links thermal stores to the feedwater heating system of a nuclear-powered steam plant is described. The storage scheme allows the plant’s electricity output to be varied while keeping reactor power constant, thereby enabling the nuclear plant to take on a load-following role. This type of ‘generation-integrated’ energy storage uses existing hardware to reduce storage costs and provides the equivalent of a high-efficiency electricity storage system. Surplus feedwater is generated during charge, which may be either stored directly or used to transfer energy to a ‘sensible-heat’ medium. By exploiting the multiple pressure bleed flows, this process is conducted with very little exergetic loss. The paper discusses (1) the off-design behaviour of steam cycle components and (2) the effect of storage heat-transfer effectiveness