1.Они умирают сами.
2.Дарю свой селект, который показывает таблички в темпдб и их размер

select (select name from tempdb..sysusers u with (nolock) where u.uid=(select uid from tempdb..sysobjects s with (nolock) where s.id=i.id)) user_name,
(select name from tempdb..sysobjects s with (nolock) where s.id=i.id)
name,rows,used*(select low from master..spt_values d with (nolock) where d.number = 1 and d.type = 'E') / 1024 size
from tempdb..sysindexes i with (nolock)
where (select type from tempdb..sysobjects o with (nolock) where o.id=i.id)='u' and indid < 2

order by size DESC ,rows DESC