蜗壳为核电站联合水泵房循环系统泵的主要组成部分，其形状像蜗牛壳，在联合水泵房中位于进水道上端，与循环水廊道相接。以宁德核电站工程为例，从蜗壳预制混凝土块的吊装和就位、蜗壳底部及接缝处灌浆、出水道模板的安装加固及安装循环水出水口测压管等方面对蜗壳模板安装技术进行了介绍，为类似工程提供参考。

Volute casing is the major component of CRF pump in united water pump house of nuclear power station, whose shape looks like a hodmadod. It is placed at the top of the water channel in PX pump house, connecting with the recycled water corridor. Taking Ningde Nuclear Power Station for example, the installation technology of volute casing formwork is introduced from the lifting and positioning of pre-cast concrete pieces of volute, grouting in the bottom and seam crossing of volute, the installation and reinforcement of the formwork of water corridor, and the installation of piezometer tubes in the outlet of circulating water and other aspects, for providing references to similar projects.