Current through Register Vol. 48, No. 38, September 20, 2024
a) The
owner or operator of a CCR surface impoundment must conduct an initial and
annual safety factor assessment for each CCR surface impoundment and document
whether the calculated factors of safety for each CCR surface impoundment
achieve the minimum safety factors specified in this Section for the critical
cross-section of the embankment. The critical cross-section is the
cross-section anticipated to be the most susceptible of all cross-sections to
structural failure based on appropriate engineering considerations, including
loading conditions. The safety factor assessments must be supported by
appropriate engineering calculations.
1) For
new CCR surface impoundments, the calculated static factor of safety under the
end-of-construction loading condition must equal or exceed
1.30.
The assessment of this loading condition is only required for the initial
safety factor assessment and is not required for subsequent
assessments.
2) The calculated
static factor of safety under the long-term, maximum storage pool loading
condition must equal or exceed
1.50.
3) The calculated static factor of safety
under the maximum surcharge pool loading condition must equal or exceed
1.40.
4) The calculated seismic factor of safety
must equal or exceed 1.00.
5) For
dikes constructed of soils that have susceptibility to liquefaction, the
calculated liquefaction factor of safety must equal or exceed
1.20.
b) The owner or operator of the
CCR surface impoundment must obtain a certification from a qualified
professional engineer stating that the initial safety factor assessment and
each annual assessment thereafter was conducted in accordance with the
requirements of this Section.
c)
Timeframe for Submission of the Safety Factor Assessment
1) The owner or operator of a new CCR surface
impoundment must submit the initial safety factor assessment certification with
the initial operating permit application before the initial receipt of CCR in
the surface impoundment.
2) The
owner or operator of an existing CCR surface impoundment must submit the
initial safety factor assessment certification with its first annual inspection
report required by Section 845.540(b).
3) The owner or operator of a CCR surface
impoundment must submit the annual safety factor assessment certification each
year with the annual inspection required by Section 845.540(b).
4) The owner or operator of a new CCR surface
impoundment must place each safety factor assessment in the facility's
operating record as required by Section 845.800(d)(6).
d) Failure to Document Minimum Safety Factors
1) For new CCR surface impoundments, until
the date an owner or operator of a CCR surface impoundment documents that the
calculated factors of safety achieve the minimum safety factors specified in
this Section, the owner or operator is prohibited from placing CCR in the CCR
surface impoundment.
2) An owner or
operator of the CCR surface impoundment who either fails to complete a timely
safety factor assessment or fails to demonstrate minimum safety factors as
required by this Section is subject to the requirements of Section
845.700.
e) The
requirements of this Section apply to all CCR surface impoundments, except for
those CCR surface impoundments that are incised CCR surface impoundments. If an
incised CCR surface impoundment is subsequently modified (e.g., a dike is
constructed) such that the CCR surface impoundment no longer meets the
definition of an incised CCR surface impoundment, the CCR surface impoundment
is subject to the requirements of this Section.
