An improved retention apparatus includes a wedge element that is disposed between a brace element and a flow element of a nuclear reactor system. The retention apparatus further includes an engagement assembly that is engaged with the wedge element and that is structured to engage at least one of the brace element and the flow element. The engagement assembly includes a deflectable element such as a spring that is structured to apply a retention force in an engagement direction of the wedge element to resist movement of the flow element during operation of the nuclear reactor system, such as movement due to vibration.