Dead calls

Hello,
I have strange problem with Asterisk 11.7.0
When i have some calls online, about 200 simultaneous open channels and my network will fall down for few seconds - some calls will not hangup up. They are still Up and call duration goes to infinite.
For example i have situation like this:

SIP/XX_-01008 fromXX +4863204 5 Up Dial SIP/sip.XX.pl/486 50046 17:24:45 SIP/sip.XX.p
SIP/XX_-01007 fromXX +4817566 5 Up Dial SIP/sip.XX.pl/481 17849 17:47:52 SIP/sip.XX.p
SIP/XX_-01008 fromXX +4347297 5 Up Dial SIP/sip.XX.pl/483 56061 17:29:27 SIP/sip.XX.p
SIP/XX_-01008 fromXX +4831256 5 Up Dial SIP/sip.XX.pl/487 44121 17:29:41 SIP/sip.XX.p
SIP/XX_-01008 fromXX +4816624 5 Up Dial SIP/sip.XX.pl/481 21566 17:27:58 SIP/sip.XX.p
SIP/XX_-01007 fromXX +4890347 5 Up Dial SIP/sip.XX.pl/489 42413 17:33:17 SIP/sip.XX.p

Is there any way to force asterisk kill dead calls?

There is a CLI hangup command.

Ok - I know it.
Is there any way to terminate dead calls automatically?
It is hard to kill 100 - 200 calls.
Also it affect CDRs with call duration.

You can enable RTP timeouts or session timers.