Liquid Wall Thickness, Life, Pumping Power, COE trade-offs

Wayne R. Meier and Ryan P. Abbott

LLNL

ARIES MeetingOct. 2-5, 2002

PPPL

Overview

HYLIFE-II design goals Examining COE for

Reduced liquid shielding thickness Lower radiation damage limits

It keeps going and going and…

HYLIFE-II design goals: Protect solid structures for full plant life Low activation with ordinary steels Reduce material development needs

A blasphemous question

What is the impact on COE of reducing the liquid wall thickness resulting in reduced first wall life and the need for periodic replacement?

Reducing liquid shielding thickness and wall life competing effects:

(+) Reduces pumping power (+) Reduces cost of circulating pumps (-) Reduces plant capacity factor (-) Increases remote maintenance equipment cost (-) Increases component replacement cost

Assumptions / Approach

Detailed model of flow rate and pumping power as function of effective shielding thickness (= geometric thickness of liquid pocket 50% liquid packing fraction) was used

Cost for recirculating pumps proportional to total flow rate Remote maintenance costs increased by 50% ($100M $150M

direct cost) Capacity factor as a function of FSW life and replacement time First wall replacement cost = $22M (½ cost of entire chamber) Other annual O&M costs proportional to plant capital cost (3% of

direct cost, standard fusion costing assumption)

Base case parameters

0.56 m effective thickness (1.12 m at 50%) 58 MWe pumping power 30 yr wall life (no replacement) 85% capacity factor based on normal plant maintenance

requirements

Wall life vs. shielding thickness

Base case100 dpa limit:0.56 m 30 yr0.40 m 10 yr

25 dpa limit:0.76 m 30 yr0.60 m 10 yr

0.2 0.3 0.4 0.5 0.6 0.70

5

10

15

20

25

30

35

100 dpa50 dpa25 dpa30 years

Effective shield thickness, m

Lif

etim

e, y

r

Pumping power vs. FSW life and dpa limit

25 dpa limit:30 yr 128 MWe10 yr 68 MWe

Base case100 dpa limit:30 yr 58 MWe10 yr 33 MWe

ltfswG 1 yr 1.05 yr 30 yr

0 5 10 15 20 25 300

20

40

60

80

100

120

140

100 dpa50 dpa25 dpa

FSW Life (yr)

Hyd

raul

ic P

ower

(M

W)

Capacity factor vs. first wall life and replacement time

0 5 10 15 20 25 300.7

0.75

0.8

0.85

Replacement time = 2 months3 months4 months

FSW Life (years)

Pla

nt C

apac

ity

Fac

tor

0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50.83

0.835

0.84

0.845

0.85

FSW Replacement Time (yr)

Pla

nt c

apac

ity

fact

or

Note:-Model assumes any life between 15 and 30 yrs requires 1 FW replacement

- We assume replacement time of 3 month in following results

COE vs. FSW life for different damage limits

0 5 10 15 20 25 300.9

1

1.1

1.2

1.3

1.4

100 dpa50 dpa25 dpa

FSW Life (years)

Nor

mal

ized

CO

E

- 100 dpa limit:>10 yr life gives COE within ~ 4% of 30 yr case

- 25 dpa limit: 30 yr COE +10%10 yr COE +7.5%

COE vs. replacement time for 5 and 10 yr wall lifetimes

0 0.1 0.2 0.3 0.4 0.51

1.05

1.1

1.15

10 yr life5 yr life

FSW Replacement Time (yr)

Nor

mal

ized

CO

E

- If wall lasts 10 yrs and takes 6 months to replace, COE only increases by 5%.

- But that may exceed acceptable plant down time for utility.

Conclusions

COE effects due to decreasing liquid shielding and/or radiation damage limits have been examined

Using current cost scaling models, 30 yr life does give minimum COE. However, wall life >10 yr have < 4% increase in COE for 100 dpa limit.

With lower damage limit of 25 dpa, COE increase by 7.5-10% for wall lifetimes of 10 and 30 yrs, respectively.

What is “marketing” value of 30 year chamber?