Stars rely on gravitation to confine the plasma instead of magnetic fields, and they can reach the energy densities needed for other fusion reactions, typically

Stars rely on gravitation to confine the plasma instead of magnetic fields, and they can reach the energy densities needed for other fusion reactions, typically D+D, which produces less neutrons. Also, there are hundreds of thousands of kilometers between the center of the sun and its outermost layers - neutrons produced in the core will have plenty of time to be absorbed by something else on their way out.