Environmental Impact Statement - radioactive monticello

Appendix G
NMC based its calculations on the value of 587 megawatt electrics (MWe), which is the current
electrical output for Monticello (after the extended power uprate). Therefore, NMC applied
power scaling factors of 587 MWe/91 0 MWe to determine the replacement power costs. For
the purposes of initial screening, which assumes all severe accidents are eliminated, NMC
calculated the AOSC to be approximately $227,500 for the 20-year license renewal period.
Using the above equations, NMC estimated the total present dollar value equivalent associated
.with completely eliminating severe accidents at Monticello to be about $4,320,000. To account
for additional risk reduction in external events, NMC doubled this value (to $8,642,000), to
provide the MMACR, which represents the dollar value associated with completely eliminating
all internal and external event severe accident risk at Monticello.
For each of the SAMAs remaining after the initial screening, the averted costs associated with
the SAMA were estimated using the above equations in conjunction with the CDF and
population dose reductions for the SAMA.
• NMC's Results
If the implementation costs for a candidate SAMA were greater than the MMACR of
$8,642,000, then the SAMA was screened from further consideration. A more refined look at
the costs and benefits was performed for the remaining SAMAs. If the implementation costs for
a candidate SAMA exceeded the calculated benefit, the SAMA was considered not to be
cost-beneficial. In the baseline analysis contained in the ER (using a 7-percent discount rate),
NMC identified seven potentially cost-beneficial SAMAs. Based on an analysis using a
3-percent real discount rate, as recommended in NUREG/BR-0058 (NRC 2004), two additional
SAMA candidates were determined to be potentially cost-beneficial. The potentially
cost-beneficial SAMAs are:
* SAMA 2-enhance dc power availability by providing a direct connection from diesel
generator 13, the security diesel, or another source to the 250 V battery chargers or other
required loads.
" SAMA 4-install a direct drive diesel injection pump as additional high pressure injection
system.
• SAMA 6-install additional fan and louver pair for EDG heating, ventilation, and air
conditioning.
* SAMA 11--enhance alternate injection reliability by including the residual heat removal
service water and FSW cross-tie valves in the maintenance program.
* SAMA 12-proceduralize the use of a fire pumper truck to pressurize the FSW system.
NUREG-1437, Supplement 26 G-24 August 2006 1