Nuclear Power Plant: (3) Vulnerability of Nuclear Plants To Attack: Nuclear reactors become preferred targets during military conflict and, over the past three decades, have been repeatedly attacked during military air strikes, occupations, invasions and campaigns: In September 1980, Iran bombed the Al Tuwaitha nuclear complex in Iraq, in Operation Scorch Sword. In June 1981, an Israeli air strike completely destroyed Iraq's Osirak nuclear research facility. Between 1984 and 1987, Iraq bombed Iran's Bushehr nuclear plant six times. In 1991, the U. S. bombed three nuclear reactors and an enrichment pilot facility in Iraq. In 1991, Iraq launched Scud missiles at Israel's Dimona nuclear power plant. In September 2007, Israel bombed a Syrian reactor under construction. In the U. S. , plants are surrounded by a double row of tall fences which are electronically monitored. The plant grounds are patrolled by a sizeable force of armed guards. The NRC's "Design Basis Threat" criteria for plants is a secret, and so what size of attacking force the plants are able to protect against is unknown. However, to scram (make an emergency shutdown) a plant takes fewer than 5 seconds while unimpeded restart takes hours, severely hampering a terrorist force in a goal to release radioactivity. Attack from the air is an issue that has been highlighted since the September 11 attacks in the U. S. However, it was in 1972 when three hijackers took control of a domestic passenger flight along the east coast of the U. S. and threatened to crash the plane into a U. S. nuclear weapons plant in Oak Ridge, Tennessee