LBNF Excavation Alternatives - PowerPoint Presentation

Slide1

LBNF Excavation Alternatives

Follow up from LBNF Risk ReviewFebruary 1st thru 4th, 2015

SURF TeamSlide2

Option 1

Lower exhaust drift

2

In Domain 4

Outside Studied Area, in domain 4 (?)

Would require another geotechnical program (perhaps adding ~ 1 year)

Lots of excavation overall and in phase

1

Phase 1 does not allow a second cryostat to be built, so filling of detector 1 is delayed until phase 2 is completeCombined exhaust may offer opportunity to combine cooling, but it will be dusty during excavationDifficult to fully isolate excavation and outfitting

Outside Studied AreaAntechamber should be longer

This is the same layout that you have seen before.Slide3

Option 1 Schedule/Cost

3

Total Cost: $

174M+$5M exhaust path = $179M

Duration to allow filling of detector 1: 37 months as shown. Could be compressed to 22 months if excavation of caverns 1 and 2 overlap

Total Duration: 60 months

Cost and schedule include antechambers and

septums (previous comparisons did not)This cost does not include the lower exhaust drift, which would add ~$5M to phase 1 (and overall) as drawn. It should not affect schedule.

Both of these are required to allow detector 1 to fillSlide4

Option 5With

septums and antechambers4

The septum and antechamber spaces can be rearranged in this layout with little impact on cost and schedule. For example, the antechamber could be in the middle.

While not shown, additional drifts would be included between antechambers and between the northern antechamber and the existing drift.

This is the same layout that you have seen before.Slide5

Option 5 Schedule/Cost

5

Total Cost: $157M

Phase 1 Duration: 20 months

Total Duration: 36 months

Cost and schedule include antechambers and

septums (previous comparisons did not)Slide6

Option 6 : “H” arrangement

CF Does not recommend this option

for several reasons:

The large intersections create stress concentrations that may not be possible in this rock mass

The

concept of installing walls at the full cavern width is not feasible for excavation isolations due to air blast

pressures without significantly reducing the efficiency of excavation

Ventilation is complicated both during construction and operation. Most heat is in the utility space, so we would like to exhaust from that space. Additional drifts above or below could help with this.

Because of items 2 and 3, all excavation would need to be completed in phase 1.Since CF does agree that a central utility space could have benefit, we offer two variations on the following slidesThis is the layout most recently proposed. The dominant new feature is a common antechamber area Slide7

Option 6 Schedule/Cost

For the reasons described on the previous slide, Option 6 has not been estimated. It is our belief, however, that this option cannot be efficiently constructed in phases as drawn, so the first and only phase would be on the scale of 3 years.

Note that it may be possible to excavate with isolation as envisioned, but the blasting techniques would be much slower and more expensive.

It

may

also be possible to excavate the large intersection as shown, but ground support would increase, increasing cost and schedule. A detailed 3d modeling of this would be required to deem whether it’s possible.

7Slide8

Option 5aParallel Central Utility Space

8

The southern cavern is outside the studied area, but we believe it may be close enough.

Since the CF and cryogenics are in a separate chamber, there is no conflict with cryostat & detector laydown

Option 5 modified by the Option 6 common antechamber concept. Slide9

Option 5a Schedule/Cost

9

Total Cost:

TBD

Duration to allow filling of detector 1: 17 months

Total

Duration: 28 monthsSlide10

Option 5bPerpendicular Central Utility Space

10

This alternative could allow for independent excavation of 4 caverns, but only with an

independent exhaust

drift (not shown)

The eastern caverns

extend into domain 4

The orientation of the central utility space is less favorable based on the

rock foliation orientation.Option 5 modified by the Option 6 common antechamber concept. Perhaps more closely tied with Option 1 Slide11

Option 5b Schedule/Cost

Option 5b has not been estimated as of this presentation. Complications with rock foliation orientation suggest that a cost and schedule based on our “normal” assumptions would be misleading.11Slide12

Comparison

Our charge was to evaluate options 1, 5, and 6. Option 6 has too many complications to be evaluated fully, but we thought that the common antechamber area was interesting enough that we decided to add options 5A and 5B to the evaluation.Jim Strait edited the list of requirements generated by

iEFIG

for

evaluations, classifying them as category 1 and 2. Jim suggested that only category 1 items be considered for comparison.

Of the category 1 requirements, we believe that 7 are considered equal across all options and are therefore not helpful in comparing options. Three others are considered to be closely interrelated, and therefore have been combined into 1.

Of the remaining requirements, 7 represent a fundamental distinction between options. The other 4 are items that require more or less design work/cost to achieve, but the core requirement can be met in any case.

The following slides attempt to summarize the “engineers” analysis of options 1, 5, 5A, 5B, and 6 using the methodology described above.

12Slide13

Category 1 items that are the same for all options

13Slide14

Category 1 items with differences between options

14The 7 criteria that represent a fundamental difference between options are highlighted in yellow and simplified and ranked on the next slide. The

other

4

are items that require more or less design work/cost to achieve, but the core requirement can be

met equally

in any case. All requirements CAN be met with any option.Slide15

Ranking and cost/schedule summary

15Criteria should be “weighted” based on

importance.

Rankings are

based on the assumptions we’ve been using for layouts and phasing.

Examples

:

Analysis to date has focused on quickest 10 kT. If the focus were on quickest 40 kT, we could approach excavation differently to make any option faster (parallel vs. serial excavation). This

could change the rank of the second row. If stress distribution is more important than fitting within the geotechnical studied area, we could spread out options and change the ranking in that row.Slide16

Comparison Schedule

16

Time during which interference would exist between excavation and all other activities

(efficiency decrease, potential damage) Slide17

Option 5 with detector construction

17Slide18

Comments CERN and FNAL Cryogenic Engineers(Johan Bremer, David Montanari, Barry Norris, Mark

Adamwoski)From the cryogenics point of view, we do not see large differences between the various options (1, 5, 5a, 5b, 6). Any potential difference is in the noise of the current estimates.

In any scenario, there will be multiple activities in parallel:

Construction of cryostat.

Construction of cryogenic system (details below).

Excavation of cavern.

The following shall be ready when the first cryostat module is ready for cool down (perhaps this could be added as requirement for CF considerations?):

Central facilities (electricity, cooling, etc.) for the common cryogenics and local cryogenics of cryostat n. 1.

Common cryogenics (at least for Cryostat n. 1)  Cold Box(es), etc.Local cryogenics for Cryostat n. 1  LAr purification, condenser, etc.As long as the work can be done safely and in parallel as needed, we believe that we can work with any of these layouts.As already pointed out by CF, we also would like to underline that, in addition to multiple construction activities going on at the same time (construction of cryostat, construction of cryogenic system, excavation of subsequent caverns), there might be the need to handle a lot of equipment up/down the Ross shaft at the same time as well: parts for the installation of cryogenic equipment and cryostat, and waste rock removed by the excavation process. Installation sequences should be studied, but all layouts will be affected in the same way.

We believe that the choice of the cavern layouts comes down to cost/schedule and CF and ODH considerations.

18Slide19

CF Concerns

All previous cost discussion has been based on unimpeded access for excavation. If excavation is slowed due to vibration control and/or scheduling blasts, the costs could rise significantly.The standard evacuation distance during blasting is 2000 feet (610m). Alternatively, blasts could be restricted to shift change times. Either way, either excavation or experiment construction schedule will be affected.

It is not possible to install cryogen piping in the Ross Shaft while excavating, nor prior to Ross Rehab completion. Installation of this piping is expected to take on the order of 6 months. This will impact critical path if excavation is phased with no delays.

If a “hiatus” is introduced between phases to allow for this, it will add cost.

For any phased excavation option, sharing the mucking ramp with deliveries of experiment equipment may be a problem. We have not addressed this.

A better understanding of the cryostat/detector installation sequence is needed. If the number of deliveries per day is low we may be able to deliver materials to the base of the pit using the lower mucking drift. If materials can be installed from the upper elevation, using the mucking drift or a dedicated installation drift is not required.

If excavation duration is too long (beyond 2024), the proposed rock disposal site may not be able to accept all waste rock.

19Slide20

Backup

These are slides that you’ve seen before, included for reference if needed.20Slide21

Alternative Excavation Comparison

1. Ross 10

kT’s

2. Parallel 10

kT’s

3. 10 + 30

kT4. Single 40 kT

5. Two 20 kTTotal Cavern Excavated Volume162,000 m3162,000 m3162,000 m3162,000 m

3162,000 m3Total Drifts

Excavated Volume86,800 m3

88,300 m

3

84,500 m

3

58,800 m

3

84,200 m

3

Distance from Ross Shaft to Common

Space (first cavern)

240m

510m

240m

240m

240m

Distance between Common Space and furthest cavern

200m

570m

220m

0m

200m

Conflict

with operation) (Rank)

2

1

3

3

2

Clean/Dirty Interface (Rank)

3

3

2

1

2

Egress (Rank)

4

2

2

1

2

Excavation

cost of phase 1 (

No escalation , EDIA, MR

)

$80M

$46M

$79M

$121M

$96M

Total

Excavation

Cost

(

No escalation

, EDIA, MR

)

$140M

$134M

$134M

$121M

$135M

Excavation

Schedule to 10

kT

19 mo

18 mo

14 mo

30 mo

17 mo

Total

Excavation

Schedule

48

mo

49 mo

46 mo

30 mo

30 mo

21

The schedules for caverns larger than 10

kT

assume excavation from both ends. 10

kT

caverns are assumed too short to allow this efficiently.

Note that there are no antechambers,

septums

, concrete pit lining or steel structure, but

this comparison has equal assumptions in all options. Options 1 and 5 have been changed in the main body of this presentation.Slide22

Septum/Antechamber Discussion

Antechamber space costs ~$90,000/m ($363/m3)Septum space costs ~$162,000/m ($223/m3), but also provides 4-5 stories of space.Discussions with the cryo group have suggested two possible solutions:

In any situation, CF requires 25m in an antechamber for electrical transformers and switchgear, chillers, air handlers, etc..

With 15m

septums

in each cavern, two caverns would have 25m antechambers for cryo equipment (50m total) and any additional caverns would have no cryo space in antechambers (25m total).

Note that whether a septum is supporting one or two cryostats, it remains 15m for this discussion. A single cryostat scenario may be able to reduce that by ~5m.

Without septums, two caverns would have 61.5m for cryo equipment (86.5m total), and any additional caverns would have 36.5m for cryo equipment (61.5m total).

Each septum wall adds $1.2M. If the cryostats are steel supported, concrete walls may not be needed, so this cost isn’t considered here.Each septum steel structure adds $2M. It is not clear whether walls or steel structure are needed in antechambers, so this cost is not considered here.22

4 Caverns w/septum

4 Caverns w/o septum

2 Caverns w/septum

2 Caverns w/o septum

1 Cavern w/septum

1 Cavern w/o septum

Total septum length

60

0

30

0

45

0

Total Antechamber length

150

296

100

173

75

133

Cost

$23,000,000

$27,000,000

$14,000,000

$16,000,000

$14,000,000

$12,000,000 Slide23

Septum, Antechamber Assumption Backup

4 cavern Scenario with septum: (4) 15m septums = 60M, (2) 50m antechambers + (2) 25m antechambers = 150m4 cavern scenario without septum: (2) 86.5m antechambers + (2) 61.5m antechambers = 296m2 cavern scenario with septum: (2) 15m septums = 30m, (2) 50m antechambers = 100m

2 cavern scenario without septum: (2) 86.5m antechambers = 170m

1 cavern scenario with

septums

: (3) 15m

septums = 45m, (2) 25m cryo equipment spaces plus 25m CF space = 75mWith a septum, the lay down space goes away.

1 cavern scenario without septums: (2) 46.5m cryo equipment spaces plus (1) 15m laydown space plus (1) 25m CF space = 133m

23Slide24

Cryo Equipment Layout

24

This equipment and

laydown

area moves to the septum if a septum is usedSlide25

CF Equipment Layout (25m)

25

Chillers

Electrical Room

Standby Generator

Standby Generator Fuel

Chilled Water Pumps and DistributionSlide26

Other costs

The table above is based on the following simplified assumptionsEach cavern adds ~$4M infrastructure cost for power, HVAC, fire protection, etc. somewhat independent of sizeEach meter of drift length costs ~$1,600 for lighting, pipes, supports, etc. (for access drifts; ramps are much less). This has a minor effect. Note that this does not account for cryogen systems.

Each month of excavation costs ~$250,000 for Construction management

Antechamber and septum costs are from the previous slide

26

1. Ross 10

kT’s

2. Parallel 10

kT’s3. 10 + 30 kT4. Single 40 kT

5. Two 20 kTAnticipated Infrastructure Cost Impact

+$12M+$13M

+$4M

Reference

+$4M

Anticipated CM Cost Addition Total

+$4.5M

+$4.75M

+$4M

Reference

+$0M

If

only

antechambers are used

+$15M

+$15M

+$4M

Reference

+$4M

If

septums

are also used

+$8M

+$8M

+$0M

Reference

+$0M

Maximum

total impact for costs other than excavation

+$31.5M

+$32.75M

+$12M

Reference

+$8M

Excavation

Cost

(from previous slide)

+$19M

+$13M

+$13M

Reference

+$14M

Maximum Total CF Impact

+$51M

+$46M

+$25M

Reference

+$22M