ML22320A115
| ML22320A115 | |
| Person / Time | |
|---|---|
| Site: | 99902076 |
| Issue date: | 12/07/2022 |
| From: | NRC/NRR/DANU/UAL2 |
| To: | Terrestrial Energy USA |
| Muniz A | |
| Shared Package | |
| ML22278B100 | List: |
| References | |
| EPID L-2021-LRO-0052 | |
| Download: ML22320A115 (8) | |
Text
OFFICIAL USE ONLY PROPRIETARY INFORMATION 7
OFFICIAL USE ONLY PROPRIETARY INFORMATION neutron shield, flux, fluence, etc.?
c)
Is helium buildup a concern in the shielding (i.e. blistering)?
- 28)
Section VII Upper Hold-down Plate a)
How is the graphite moderator secured? Does the upper hold-down plate simply
((
)) or does it consist of components such as an adapter plate, enclosure, hold-down springs, clamps, and pads?
- 29)
Section VII Shutdown Rods a)
Are the shutdown rods seismically qualified? Are they considered safety-related?
- 30)
Section VII Load Combinations a)
The white paper describes national building standards as being used in seismic response evaluations of the core-unit design. Additional information will be needed to understand what the national building standards are and how they relate to NRC requirements. The NRC staff notes that RG 1.92, Combining Modal Responses and Spatial Components in Seismic Response Analyses, and NUREG-0484, Methodology for Combining Dynamic Responses, provide guidance regarding load combinations.
- 31)
Section VII Acceptance Criteria a)
What service level is mandated for the components related to the shutdown rods? Describe how the chosen service level does not allow for gross plastic deformation which could prevent insertion of the shutdown rods.
- 32)
Section VII Core-unit Externals a)
Is the guard vessel affected by the gamma-ray/radiation swelling over the lifetime of the plant? Is the guard vessel monitored or inspected?
- 33)
Section VIII Start-up a)
How will the fuel be initially melted? How will the Initial Fuel System interface with the core-unit?
- 34)
Section VIII Low-Power and Critical a)
Since the start-up section concludes with reaching criticality, the NRC staff assumes that this section is supposed to be titled simply Low-Power. Is this correct?
- 35)
Section VIII High-Power/Full-Power a)
What is the sequence for shutting down? In a future core-unit SDA application, describe the shutdown states in detail (hot, warm, cold) and what sequence operators would need to follow to safely shut down the reactor.
OFFICIAL USE ONLY PROPRIETARY INFORMATION 8
OFFICIAL USE ONLY PROPRIETARY INFORMATION
- 36)
Section VIII Core-swap a)
Additional details about the core-swap procedure will be necessary during the core-unit SDA to help the NRC staff understand possible failures that could occur (e.g. could a spent core drop from a crane during maneuvers and land on or otherwise impact the operational core).
b)
Additional description about how the robotic manipulators disconnect (and later connect) the core-unit from the secondary side will be necessary during the core-unit SDA application. In particular, the NRC staff will be interested in any potential initiating events that could occur while connecting a core-unit to the secondary side.