We introduce a class of notions of forcing which we call
$\Sigma $
-Prikry, and show that many of the known Prikry-type notions of forcing that centers around singular cardinals of countable cofinality are
$\Sigma $
-Prikry. We show that given a
$\Sigma $
-Prikry poset
$\mathbb P$
and a name for a non-reflecting stationary set T, there exists a corresponding
$\Sigma $
-Prikry poset that projects to
$\mathbb P$
and kills the stationarity of T. Then, in a sequel to this paper, we develop an iteration scheme for
$\Sigma $
-Prikry posets. Putting the two works together, we obtain a proof of the following.
Theorem. If
$\kappa $
is the limit of a countable increasing sequence of supercompact cardinals, then there exists a forcing extension in which
$\kappa $
remains a strong limit cardinal, every finite collection of stationary subsets of
$\kappa ^+$
reflects simultaneously, and
$2^\kappa =\kappa ^{++}$
.