ML16266A546

Summary of Results of Flooding Hazard Reevaluation Report for Millstone Power Station Units 2 and 3

ML16266A546
Person / Time
Site:	Millstone
Issue date:	12/21/2016
From:	Aida Rivera-Varona NRC/NRO/DSEA/RHMB
To:
Rivera-Varona A
References
Download: ML16266A546 (6)

Text

Millstone Power Station, Unit 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Design Basis Reference Elevation Runup Hazard Elevation Local Intense Precipitation 14.5 ft Minimal 14.5 ft FHRR Table 1.2-1 NGVD29 NGVD29 Streams and Rivers No Impact No Impact No Impact FHRR Table 1.2-1 on the Site on the Site on the Site Identified Identified Identified Failure of Dams and Onsite Water Control/Storage Structures Not included Not included Not included FHRR Sections 2.3.3 & 3.3 in DB in DB in DB Storm Surge Storm Surge (standing wave) 26.5 ft Not 26.5 ft FHRR Sections 1.5 and 3.4 within the Intake Structure for NGVD29 applicable NGVD29 Unit 2 Storm Surge at the Powerblock 18.1 ft 7.0 ft 25.1 ft FHRR Section 3.9 and FHRR Table NGVD29 NGVD29 3.0-1 FHRR Table 1.2-1 Seiche No Impact No Impact No Impact FHRR Table 1.2-1 on the Site on the Site on the Site Identified Identified Identified Tsunami Not included Not included Not included FHRR Table 1.2-1 in DB in DB in DB Ice-Induced Flooding No Impact No Impact No Impact FHRR Table 1.2-1 on the Site on the Site on the Site Identified Identified Identified

Millstone Power Station, Unit 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Design Basis Reference Elevation Runup Hazard Elevation Channel Migrations/Diversions No Impact No Impact No Impact FHRR Table 1.2-1 on the SIte on the Site on the Site Identified Identified Identified Note 1: Reported values are rounded to the nearest one-tenth of a foot.

Millstone Power Station, Unit 2 Table 2. Reevaluated Flood Hazards for Flood-Causing Mechanisms for Use in the MSA Mechanism Stillwater Waves/ Reevaluated Reference Elevation Runup Hazard Elevation Local Intense Precipitation 17.5 ft Minimal 17.5 ft FHRR Section 3.1 NGVD29 NGVD29 Streams and Rivers 11.2 ft Not 11.2 ft FHRR Section 2.2 NGVD29 applicable NGVD29 Storm Surge Under Under Under Review Review Review Tsunami 14.7 ft Not 14.7 ft FHRR Section 2.6 NGVD29 applicable NGVD29 Note 1: The licensee is expected to develop flood event duration parameters and applicable flood associated effects to conduct the MSA. The staff will evaluate the flood event duration parameters (including warning time and period of inundation) and flood associated effects during its review of the MSA.

Note 2: Reevaluated hazard mechanisms bounded by the current design basis (see Table 1) are not included in this table.

Note 3: Reported values are rounded to the nearest one-tenth of a foot.

Millstone Power Station, Unit 3 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Design Basis Reference Elevation Runup Hazard Elevation Local Intense Precipitation RWST/SIL Valve Enclosure 24.9 ft Minimal 24.9 ft FHRR Table 1.2-3 and Table 3.0-3 NGVD29 NGVD29 Demineralized Water Storage 24.9 ft Minimal 24.9 ft FHRR Table 1.2-3 Tank Block House NGVD29 NGVD29 Fuel Building 24.9 ft Minimal 24.9 ft FHRR Table 1.2-3 NGVD29 NGVD29 Auxiliary Building Door A-24-6 24.9 ft Minimal 24.9 ft FHRR Table 3.0-3 NGVD29 NGVD29 Engineered Safety Features 24.9 ft Minimal 24.9 ft FHRR Table 1.2-3 Building NGVD29 NGVD29 Hydrogen Recombiner Building 24.9 ft Minimal 24.9 ft FHRR Table 1.2-3 NGVD29 NGVD29 Main Steam Valve Building 24.9 ft Minimal 24.9 ft FHRR Table 1.2-3 NGVD29 NGVD29 Emergency Generator Enclosure 24.3 ft Minimal 24.3 ft FHRR Table 1.2-3 NGVD29 NGVD29 Auxiliary Building Door A-24-1 24.9 ft Minimal 24.9 ft FHRR Table 3.0-3 NGVD29 NGVD29 Control Building 24.3 ft Minimal 24.3 ft FHRR Table 1.2-3 NGVD29 NGVD29 Streams and Rivers No Impact No Impact No Impact FHRR Table 1.2-2 on the Site on the Site on the Site Identified Identified Identified

Millstone Power Station, Unit 3 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Design Basis Reference Elevation Runup Hazard Elevation Failure of Dams and Onsite Water Control/Storage Structures Not included Not included Not included FHRR Sections 2.3.3 & 3.3 in DB in DB in DB Storm Surge Storm Surge at Seaward Wall of 19.7 ft 21.5 ft 41.2 ft FHRR Section 3.9 Intake Structure for Unit 3 NGVD29 NGVD29 Storm Surge at Powerblock 19.7 ft 4.1 ft 23.8 ft FHRR Section 1.5 NGVD29 NGVD29 FHRR Table 1.2-2 Seiche No Impact No Impact No Impact FHRR Table 1.2-2 on the Site on the Site on the Site Identified Identified Identified Tsunami Not included Not included Not included FHRR Table 1.2-2 in DB in DB in DB Ice-Induced Flooding No Impact No Impact No Impact FHRR Table 1.2-2 on the Site on the Site on the Site Identified Identified Identified Channel Migrations/Diversions No Impact No Impact No Impact FHRR Table 1.2-2 on the SIte on the Site on the Site Identified Identified Identified Note 1: Reported values are rounded to the nearest one-tenth of a foot.

Millstone Power Station, Unit 3 Table 2. Reevaluated Flood Hazards for Flood-Causing Mechanisms for Use in the MSA Mechanism Stillwater Waves/ Reevaluated Reference Elevation Runup Hazard Elevation Streams and Rivers 11.2 ft Not 11.2 ft FHRR Section 2.2 NGVD29 applicable NGVD29 Storm Surge Under Under Under Review Review Review Tsunami 14.7 ft Not 14.7 ft FHRR Section 2.6 NGVD29 applicable NGVD29 Note 1: The licensee is expected to develop flood event duration parameters and applicable flood associated effects to conduct the MSA. The staff will evaluate the flood event duration parameters (including warning time and period of inundation) and flood associated effects during its review of the MSA.

Note 2: Reevaluated hazard mechanisms bounded by the current design basis (see Table 1) are not included in this table.

Note 3: Reported values are rounded to the nearest one-tenth of a foot.