关于核衰变和核反应的类型，下列表述正确的有（）

A．	${}_{92}{}^{238}U\to {}_{90}{}^{234}Th+{}_2{}^{4}He$是 $\alpha$衰变	B．	${}_7{}^{14}N+{}_2{}^{4}He\to {}_8{}^{17}O+{}_1{}^{1}H$是 $\beta$衰变
C．	${}_1{}^{2}H+{}_1{}^{3}H\to {}_2{}^{4}He+{}_0{}^{1}n$是轻核聚变	D．	${}_{34}{}^{82}Se\to {}_{36}{}^{82}Kr{}_2{}^{4}He+2{}_{-1}{}^{0}e$是重核裂变