Chris,
I think that your & Glen's points are very good.
I would just like to add some numbers to the point Glen was making -- FYI, the wingspan of a Boeing 767 (for example) is 47.6m (as compared, for example, to the 44m O.D. of a CANDU-6 containment dome), but its engines are only 15.6m apart - or 7.8m from the plane's center line. So if the plane were to impact with its fuselage centerline exactly aligned with the building centerline, then the engines would impact on the wall at an angle of 69° -- ie. 21° off perpendicular (and assuming a perfectly in-plane horizontal approach at an altitude of only a dozen-or-so metres !!! ....the width of the fuselage is 5m and overall height is 15.9m.... normal runway approach speed with MLW - maximum landing weight - is about 165mph or 265kph, according to Jane's All the World's Aircraft).
As Glen said, for missiles "striking concrete structures.... there is a significant reduction in
penetration if the impact vector is anything other than normal to the impact surface. Even if the containment were flat, if the shaft of the engine did not strike the surface perpendicularly, the shaft will rotate and slam broadside into the containment. The force instead of being over the cross
sectional area of the end of the (airliner engine) shaft is then dispersed over the entire cross sectional are of the long side of the shaft. The resultant penetration is <5% of that for a normally incident crash."
Its very unlikely that a perfectly perpendicular impact could be achieved on a cylindrical structure, unless you put the plane on a rail track, like the F-4 Phantom in the 1988 Sandia test, with an 8m offset from the center line of the building....
Thanks very much, Glen.
I also agree with Chris on stomping hard on terrorism.
Statements about the world having changed since September 11 apply to terrorist too though, I think : Its amazing how quickly word gets around that passengers in a highjacked airliner can no longer assume that obeying the highjackers' orders will lead to a peaceful end to the hostage situation -- passengers in the fourth highjacked plane on Sept. 11 got word of what happened, and that was the end of any more suicide impacts into city highrise office buildings or national monuments, or what have you. The terrorists end up dead either at the hand of courageous passengers, or by slamming into the ground. It must be pretty obvious to them, that such a tactic will simply not work again -- regardless of any additional security measures at airports, reinforcing of cockpit doors, arming the pilots or putting air marshals on board, intercepting errant flights with military jets, etc. etc.
Suggestions for deployments of anti-aircraft missile batteries at NPPs seem to make little sense at this point. They are clearly intended to intensify public fear of nuclear.
As someone else wrote on another listserv in late September,
"How many people are on the LA freeway each morning with tankers full of gasoline, ammonia, chlorine, and who knows how many other highly toxic and/or explosive materials? Should we provide armed guards for every tanker that carries hazardous material? Huge tanks of propane, chlorine, and ammonia are all over every large city. And ammonia is used as the refrigerant in the A/C systems of huge buildings, like sports arenas, with tens of thousands of spectators and poor ventilation. In all seriousness, I wish they would have targeted nuclear plants...far less people would have been killed."
Jaro
-----Original Message-----
From: E. Chris Horley [mailto:ehorley@lanl.gov]
Sent: Thursday November 08, 2001 1:12 PM
To: glen.vickers@EXELONCORP.COM; radwaste@RWMA.COM;
radsafe@list.vanderbilt.edu; frantaj@AECL.CA
Subject: RE: nuclear plant threat
Having designed and analyzed nuclear containment and emergency systems for
15 years, I have to weigh in on this. Rather than postulate multitudes of
impact scenarios and counter technical arguments, the fundamental truth is
that a fully loaded 767 with a transcontinental load of fuel is a
significant adversary for a nuclear plant. In fact, it is a significant
adversary to any man made item from above ground to 50 below ground. (If
you don't like my 50ft, pick your own number). It is one hell of a bomb. So
let's stay focused on the real issue of how to make these flying bombs
terror proof.
If someone perseverates over the vulnerability and impact of an attack on a
nuclear plant, I can help add over a 1000 other targets to their list and
the attendant damage each will cause. If this is not enough to dilute their
nuclear power focus, then we can get into the biological, chemical and
nuclear threat arenas. In the end, everyone has a right to stay in denial.
In a free society, we are at risk and must recognize and accept it. And
stomp hard on terrorism.
These of course are my personal views.
Chris Horley
E. Chris Horley, P.E.
Los Alamos National Laboratory
NIS-5, Safeguards Science Technology
505-667-0639
505-665-4433 FAX