In the present work some aspects of cavitation influence on the European Spallation Source (ESS) liquid metal target are investigated. The analysis is based on a calculation of a bubbles’ radius change for bubbles moving along a changing pressure field. The two main cases are studied: a vapour cavitation (only liquid’s vapour is inside a bubble) and a mixed cavitation (in addition to a vapour a gas is inside a bubble). A simplified pressure model is obtained from numerical investigation of fluid flow in the ESS model. The main goal of this work is to determine conditions leading to growth or collapse of bubbles.