ML14071A456
Text
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.4-11 Line of Demarcation for Historical Storm Central Pressure Analysis 41.5°N, 71°W 36.5°N, 76°W Legend PSEG Site Page 2-98
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.4-12 Nested SWAN Grid Resolution Comparison Page 2-99
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.4-13 Nested SWAN Validation Points Coarse vs. Nested Sig. Wave Height, Point 1
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.4-14 Comparison of Still Water Level and Total Water Level at Point 1 - HCGS SWIS North Wall Point 1 Hope Creek Water Intake North Max TWL versus Max SWL for Each Event 10 9
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Figure 2.4-15 Comparison of Still Water Level and Total Water Level at Point 2 - HCGS SWIS West Wall Point 2 Hope Creek Water Intake West Max TWL versus Max SWL for Each Event 1 1 r----.----.----,----,-----,----.----.-~~
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Page 2- 101 Sargent & L.undy~~ "
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.4-16 Comparison of Still Water Level and Total Water Level at Point 3 - HCGS SWIS South Wall Point 3 Hope Creek Water Intake South Max TWL versus Max SWL for Each Event I , I , I I ,
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Figure 2.4-17 Comparison of Still Water Level and Total Water Level at Point 4 - HCGS SWIS East Wall Point 4 Hope Creek Water Intake East Max TWL versus Max SWL for Each Even!
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Page 2-102 Sargent & Lundy ~ ~ ~
PSEG Nuclear LLC SL-01 2271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.4-18 Comparison of Still Water Level and Total Water Level at Point 19 - HCGS West Wall Point 19 Hope Creek Generating Station West Max TWL versus Max SWL for Each Event
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Figure 2.4-19 Comparison of Still Water Level and Total Water Level at Point 20 - HCGS South Wall Point 20 Hope Creek Generating Station South Max TWL versus Max SWL for Each Event 11
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Page 2-103 Sargent & LundyllC
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.4-20 Comparison of Still Water Level and Total Water Level at Point 22 - HCGS North Wall Point 22 Hope Creek Generating Stati on North Max TWL versus Max SWL for Each Event 1 0r----.----.----.----.-----.----.----.---~
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Page 2-104 Sargent & Lundy'I. e
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.5 SEICHE Seiche is an extreme sloshing of an enclosed or partially enclosed body of water excited by meteorological causes (e.g., barometric fluctuations, storm surges, and variable winds),
interaction of wave trains with geometry and bathymetry of the water body (e.g., from tsunamis),
and seismic causes (e.g., a local seismic displacement resulting in sloshing of the water body).
Seiche motion can be complex in water bodies with variable width and depth. The simplest seiche motion in an estuary like Delaware Bay causes the largest water level fluctuations at the head of tide (near Trenton, NJ) while water levels are relatively constant at the mouth of the bay. This type of seiche is called the fundamental mode (Reference 2.5-2). The free oscillation period of the fundamental mode seiche propagating along the length of the Delaware Estuary from its mouth at RM 0 to the head of tide at Trenton (RM 134) is 31 hrs.
Shorter length seiche waves (with shorter oscillation periods) are possible. The effect of winds blowing along the axis of Delaware Bay (northwest-southeast) may excite a seiche within Delaware Bay, but with little effect on the upper estuary, due to the change in orientation of the river in the upper estuary (more nearly northeast-southwest) and less surface area for the wind to act on. Therefore, winds from the northwest tend to excite a shorter length wave with greater effect in Delaware Bay and less effect in the upper estuary. Fluctuations in the strength of northwest winds could generate seiche waves of the second mode, which have a period of 10 hrs. (Reference 2.5-2).
Researchers have observed water level fluctuations in Delaware Bay that have lower frequency than tides, which are semidiurnal (indicating 12-hour periods). Water level fluctuations that have lower frequency than tides are referred to as subtidal. The magnitude of such subtidal oscillations observed by these researchers at the PSEG Site was less than 2 ft. Researchers further determined that these water level fluctuations are associated with wind forces of two types. The first type is direct wind stress on the surface of Delaware Bay, while the second is an indirect forcing associated with wind stress fluctuations over the Atlantic Ocean. The fluctuations in wind stress are associated with fluctuations in water levels in the Delaware Bay at periods of more than 3 days. Together, these direct and indirect wind stress fluctuations are associated with nearly all subtidal fluctuations of water surface elevations observed at Reedy Point, DE, 7 mi. from the PSEG Site. (References 2.5-3 and 2.5-4)
From the observations reported, it can be seen that the atmospheric forcing, associated with seiche motion in Delaware Bay, occurs with longer periods (more than 3 days) than the natural period of oscillation of the Delaware Estuary (30 hrs. or less). Therefore, Delaware Bay does not resonate with the meteorologically-induced wave periods. This lack of resonance contributes to the relatively small magnitude of seiche motion in Delaware Bay.
The Delaware Bay also would not resonate with seismic activity. Seismic waves have a period of 1 hr. or less (Reference 2.5-1). Subsection 2.6 documents the effect of tsunami-induced seiche motion in Delaware Bay, showing that the magnitudes of water level fluctuations are too small to affect safety-related SSC.
Due to the lack of resonance with identified forcing functions, as well as observational evidence of the relatively small magnitude of seiche motions, potential seiche waves produce much smaller flood levels than the hurricane based storm surge.
Page 2-105
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.5.1 References 2.5-1 Oliver, J., A Summary of Observed Seismic Surface Wave Dispersion, Bulletin of the Seismological Society of America, 52: p. 81 - 86, 1962.
2.5-2 U.S. Army Corps of Engineers, Coastal Engineering Manual, Engineer Manual 1110-2-1100, United States Army Corps of Engineers, Washington, D.C. (in 6 volumes), 2002.
2.5-3 Wong, K. and J.E. Moses-Hall, On the Relative Importance of the Remote and Local Wind Effects to the Subtidal Variability in a Coastal Plain Estuary, Journal of Geophysical Research, 103: p. 18,393 - 404, 1998.
2.5-4 Wong, K. and R.W. Garvine, Observations of Wind-Induced, Subtidal Variability in the Delaware Estuary, Journal of Geophysical Research 89: p. 10,589 - 597, 1984.
Page 2-106
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.6 TSUNAMI The tsunami analysis presented in the PSEG Site ESPA SSAR is prepared using methodologies based on present-day regulatory guidance and is directly applicable to HCGS (Reference 2.6-1).The SSAR describes the tsunami analysis conducted using the MOST model and a range of distant and near field sources, including a subduction zone event in the Hispaniola Trench, a volcanic cone collapse in the Canary Islands, and a Currituck landslide event on the continental shelf margin. Runup values calculated during simulations are relative to 10 percent exceedance high tide, which serves as the static initial water level in the simulations.
Drawdown values calculated during simulations are relative to the 90 percent exceedance low tide elevation. The 10 percent exceedance high tide is 4.5 ft. NAVD and 90 percent exceedance low tide is -5.08 ft. NAVD based on historical observation data from the NOAA tidal gage at Reedy Point (Reference 2.6-2). This provides an approximation for extreme water levels reached for wave runup events arriving coincident with high astronomical tide, or for drawdown events arriving coincident with low astronomical tide. The probable maximum tsunami (PMT) at the PSEG Site is caused by the Currituck Landslide. In the most conservative model without bottom friction, maximum runup at the PSEG Site is 5.65 ft. NAVD and maximum drawdown is
-6.16 ft. NAVD. (Reference 2.6-1)
The U.S. Nuclear Regulatory Commission issued JLD-ISG-2012-06 (Reference 2.6-3), which provides guidance on tsunami analysis. The methodologies used in developing the PMT analysis for the PSEG Site were reviewed against the current regulatory guidance. The guidance includes the following statement, which requires clarification relative to the methodologies employed for the PSEG Site:
Computational modeling tools based on the shallow-water equation have been shown to be reasonably accurate throughout the evolution of a tsunami, and are widely used.
However, these tools lack the capability to simulate dispersive waves, which could be the predominate features in landslide-generated tsunami, and for tsunami traveling a long distance. (Section 3.5, page 9)
This statement applies to the MOST model used in the PSEG Site ESPA SSAR analysis, which is a shallow-water equation model. The SSAR analysis showed, however, that the high frequency components of the wave train corresponding to the Currituck landslide case, which is taken to be the probable maximum tsunami (PMT) event, are strongly filtered by physical processes in Delaware Bay, and are not critical to the final runup or drawdown estimates at the PSEG Site. The resulting wave train at the PSEG Site is characterized by timescales which fall within the range of validity for a simulation of the region based on shallow-water equations.
Therefore, the PSEG Site ESPA SSAR analysis is valid within the scope of the more recent JLD-ISG-2012-06 guidelines.
2.6.1 Conclusions Hope Creek Generating Stations is immediately adjacent to the proposed new plant on the PSEG Site and is subject to the same potential flooding due to PMT. The PMT event does not lead to flooding anywhere on the PSEG Site, including the Salem and Hope Creek Generating Stations. The site is not subject to drawdown effects or velocity effects due to PMT that require further analysis. Therefore, the tsunami event is not a viable flood causing mechanism at the PSEG Site.
Page 2-107
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.6.2 References 2.6-1 PSEG Power, LLC and PSEG Nuclear, LLC. PSEG Site Early Site Permit Application, Part 2, Rev.2, Subsection 2.4.6. 2013.
2.6-2 National Oceanic and Atmospheric Administration, Sea Level Trends Online, 8551910 Reedy Point, Delaware, Website, http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8551910.
2.6-3 U.S. Nuclear Regulatory Commission, Interim Staff Guidance for Performing a Tsunami, Surge, or Seiche Hazard Assessment, JLD-ISG-2012-06, January 2013.
Page 2-108
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.7 ICE INDUCED FLOODING The ice effects analysis presented in the PSEG Site ESPA SSAR is prepared using methodologies based on present-day regulatory guidance and is directly applicable to HCGS (Reference 2.7-1). This analysis simulates the historical worst ice jam upstream of the PSEG Site on record, based on the USACE Cold Regions Research and Engineering Laboratory (CRREL) Ice Jam Database (Reference 2.7-2). HEC-RAS was used to determine water levels in the Delaware River at the PSEG Site due to the postulated failure of the worst historical upstream ice jam. The resulting 8.1 ft. NAVD water surface elevation at the PSEG Site, is due to the combination of the 10 percent exceedance high tide (4.5 ft. NAVD), the spring base flows (0.7 ft.), the rise in the Delaware River resulting from the upstream ice jam breach at Trenton (0.1 ft.), and the coincident wave runup from a 2-year wind speed applied in the critical direction (2.8 ft.).
The CRREL Ice Jam Database was re-evaluated in January 2013 for recent flood events since preparation of the SSAR analysis, and no recent ice jam events more severe than the historical event modeled for the SSAR was identified (Reference 2.7-2). Based on review of historical ice jam information and model simulation performed for the SSAR (Reference 2.7-1) of a major historic ice jam event, the flooding potential resulting from historic ice jam discharge is elevation 8.1 ft. NAVD at the PSEG Site.
The resulting 8.1 ft. NAVD water surface elevation at the PSEG Site, is due to the combination of the 10 percent exceedance high tide (4.5 ft. NAVD), the spring base flows (0.7 ft.), the rise in the Delaware River resulting from the upstream ice jam breach at Trenton (0.1 ft.), and the coincident wave runup from a 2-year wind speed applied in the critical direction (2.8 ft.).
2.7.1 Conclusions This flood elevation is considered applicable to HCGS, as HCGS is downstream of the new plant on PSEG Site. The flood elevation (8.1 ft. NAVD) resulting from the ice effects is below the lowest grade elevations of safety-related structures (excluding water intake structures) at HCGS, located at elevation 9.0 ft. NAVD. Therefore, an ice-induced event is not a viable flood causing mechanism at the PSEG Site.
2.7.2 References 2.7-1 PSEG Power, LLC and PSEG Nuclear, LLC. PSEG Site Early Site Permit Application, Part 2, Rev.2, Subsection 2.4.7. 2013.
2.7-2 U.S. Army Corp of Engineers (USACE). Cold Regions Research and Engineering Laboratory, Ice Jam Database, Website, https://rsgisias.crrel.usace.army.mil/apex/f?p=273:1:, accessed January 2, 2013.
Page 2-109
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.8 CHANNEL MIGRATION OR DIVERSION The channel diversion and migration analysis presented in the PSEG Site ESPA SSAR is prepared using methodologies based on present-day regulatory guidance and is directly applicable to HCGS (Reference 2.8-1).The Delaware River has been flowing in its current channel at least since the last ice age, approximately 10,000 years ago. There is no historical evidence of channel diversions of significance in the Delaware River Basin. There are no levees on the Delaware River, only on tributaries to the river. The collapse or breaching of a levee or dam on upstream tributaries would not cause a flood at the PSEG Site, as discussed in Subsection 2.3.
The potential for channel diversions caused by landslide, mudslide, or other temporary diversion of flow either directly upstream or downstream of the PSEG Site is highly unlikely due to the shallow nature of the lower Delaware River and the flat topography near the PSEG Site.
2.8.1 Conclusions The analysis presented in the PSEG Site ESPA SSAR concludes that given the seismic, topographical, geologic, and thermal evidence in the region, there is very limited potential for upstream diversion or rerouting of the Delaware River (due to channel migration, river cutoffs, ice jams, or subsidence) and therefore, no adverse impacts to safety-related SSCs are postulated. Therefore, channel diversion and migration is not a viable flood causing mechanism at the PSEG Site.
2.8.2 References 2.8-1 PSEG Power, LLC and PSEG Nuclear, LLC. PSEG Site Early Site Permit Application, Part 2, Rev.2, Subsection 2.4.9. 2013.
Page 2-110
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.9 COMBINED FLOOD EFFECT Combined effect of different flood-causing mechanisms is evaluated based on the guidelines presented in NUREG/CR-7046 (Reference 2.9-1) and ANSI/ANS-2.8-1992 (Reference 2.9-2),
which provide detailed guidance on selecting combined events criteria for power reactor site locations on inland streams, open or semi-enclosed bodies of water, and enclosed bodies of water.
Flooding reevaluations for different flood mechanisms are described in Sections 2.1through 2.8.
As described in this report, dam failure (Section 2.3), seiche (Section 2.5), tsunami (Section 2.6), ice-induced flooding (Section 2.7), and channel diversion (Section 2.8) have no impact to any safety-related SSCs of the HCGS. These flood mechanisms are screened out as not applicable to the site based on the topographic, geological, and hydrologic environment.
Therefore, a combined effect flooding assessment for these mechanisms is not necessary.
Reevaluation of the LIP event in Section 2.1 identifies that the SSCs could be flooded from a local PMP event if the watertight doors are not closed ahead of the event. NUREG/CR-7046 (Reference 2.9-1) and ANSI/ANS-2.8-1992 (Reference 2.9-2) do not provide combined effect criteria for a LIP event.
The analysis of flooding in streams and rivers (Section 2.2) uses the combined effect guidance presented in ANSI/ANS-2.8-1992 (Reference 2.9-2) and NUREG/CR-7046 (Reference 2.9-1) to develop the overall water surface elevation at the site. This analysis concluded that the storm surge and tidal components of the combined effect flood dominate the total water surface elevation. Since these aspects of the combined effect flood dominate the total water surface elevation, wave run-up analysis is not undertaken as the storm surge evaluation described in Section 2.4 bounds the storm surge events addressed in Section 2.2.
The effect of hurricane storm surge is reevaluated in Section 2.4. Due to the complex nature of the storm surge analysis presented, the combined effects considered for this event (river discharge, tidal effects, and wave run-up) are discussed in detail in Section 2.4.
2.9.1 Conclusions The reevaluation of flood causing mechanisms for the PSEG Site indicates that the LIP event and the maximum storm surge including wave runup are the controlling flooding mechanisms for the site. Appropriate combined event criteria for these flooding events are included in the evaluations.
2.9.2 References 2.9-1 U.S. Nuclear Regulatory Commission, Design-Basis Flood Estimation for Site Characterization at Nuclear Power Plants in the United States of America, NUREG/CR-7046, November 2011.
2.9-2 Determining Design Basis Flooding at Power Reactor Sites, American National Standards Institute/American Nuclear Society, ANSI/ANS-2.8-1992, Nuclear Standard 2.8, 1992.
Page 2-111
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.10 ASSOCIATED EFFECTS Reference 2.10-2 defines Flood height and associated effects as:
The maximum stillwater surface elevation plus the following factors:
wind waves and run-up effects; hydrodynamic loading, including debris; effects caused by sediment deposition and erosion; concurrent site conditions, including adverse weather conditions; groundwater ingress; and other pertinent factors.
Analysis of wind waves and run-up effects is discussed in Section 2.9; the remaining items are discussed below.
2.10.1 Hydrostatic and Hydrodynamic Loads At the PSEG Site, the critical flood causing mechanism in terms of flood height and wave action is the storm surge event. Therefore, to address the associated effect of hydrostatic and hydrodynamic loads, the storm surge event discussed in Section 2.4 is further evaluated.
Section 2.4 describes a probabilistic methodology to establish the 10-6 AEP still and total WSEL at critical points around the PSEG Site. There currently exists no guidance on translating these probabilistic results to a detailed hydrodynamic loading analysis; therefore, a suite of representative storms were selected to represent the 10-6 event.
Table 2.10-1 presents a tabulation of of the subset of storms that bracket the still WSEL presented in Section 2.4 along with the storm parameters considered (radius to maximum winds, storm track, landfall displacement, central pressure, forward speed, and Holland B) and the simulated SWL results for each storm. The 10-6 AEP still WSEL (22.0 ft. or 6.7 m NAVD) identified in Section 2.4 has a tidal adjustment of 0.18 m included. For comparison purposes, the tidal adjustment was added to the still WSEL for the subset of storm events. This yields adjusted still WSEL values of 6.89 m, 7.19 m, 6.93 m, 6.42 m, 6.46 m, and 6.55 m for Storms 11, 20, 21, 25, 33, and 60, respectively. The average of the adjusted SWL for the selected storms is 6.7 m, which matches the flood level (6.7 m) identified in Section 2.4 to represent the 10-6 AEP still WSEL.
The 10-6 AEP still WSEL also includes aleatory uncertainty in the probabilistic calculations; however, this uncertainty is difficult to accurately specify for each storm event in a deterministic sense so it is not assigned to the selected storms events in Table 2.10-1. The six storms were selected to average to the 10-6 AEP still WSEL with aleatory uncertainy value (as opposed to the 19.4 ft. (5.9 m) NAVD still WSEL value discussed in Subsection 2.4.3.6 that does not include the effect of aleatory uncertainty) to represent the design flood level (including aleatory uncertainty) for the deterministic calculations performed in Section 2.10. In addition, the selected storms in Table 2.10-1 represent a variety of storm parameters evaluated in Section 2.4. For example, two different radius to maximum wind values, two different Holland B parameters, three different landfall locations, and three different approach angles are represented in this subset of storms. Including multiple storms events in this analysis allows for varied surge and wave conditions to be evaluated, which is advantageous over choosing just Page 2-112
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 one of the storms from Section 2.4 (e.g., Storm 11) that most closely matches the 10-6 AEP still WSEL. The singular storm approach could, for example, miss potentially important factors that are important at some locations but less important at others. As a result, the subset of storms selected for final analysis in the wave and debris force calculations provides a representative sample of the overall JPM analysis, both in terms of average still WSEL and variety of storm parameters.
Following regulatory guidance provided in Reference 2.10-3, the methodology provided in the USACE Coastal Engineering Manual (Reference 2.10-4) is used for computing hydrostatic and hydrodynamic loads against inundated vertical surfaces. The specific method was developed by Goda and Tanimoto et al. (References 2.10-5 and 2.10-6) and is presented in CEM Table VI 53 and as Figure 2.10-1.
The methodology adopted assumes that the waves are not experiencing local breaking, which is a justifiable assumption at the PSEG Site due to wave blocking, diffraction, and scattering by the buildings and as indicated by the nested SWAN model results. The Goda method accommodates obliquely incident waves with wave angle defined in Figure 2.10-1, and it also assumes that the vertical wall causes a reflected or standing wave against the waterside of the wall with the crest of the wave at an elevation greater than one-half of reflected wave height due to wave nonlinearity (the 0.75(1+cos) parameter in *). Because Godas method does not include the hydrostatic contribution of the total force on the wall, this was added to the wave force to produce the total force on the wall. The hydrostatic force (Fh), in terms of the variables in Figure 2.10-1, is defined as Fh = wgh2, where w is the density of seawater, g is gravitational acceleration, and h is the depth of water at the wall.
Table 2.10-2 lists the maximum calculated total wave loading (hydrostatic and hydrodynamic) in kips/ft of wall for each of the critical points for the six storms determined to bracket the 10-6 AEP storm surge event. It includes for each point: wave loading in kips/ft and the average load for the point. It can be seen that locations on the river side of the intake structures, which front directly on to the Delaware Bay, have the highest wave loads. Subsection 3.10.1 of this report shows a comparison to the existing design total wave loading combinations at critical locations around the site.
2.10.2 Debris Loads To consider the potential impact loads due to floating debris during a severe storm, the following steps are taken:
Establish the Floating Debris Spectrum Apply an Appropriate Impact Load Methodology for Critical Locations around the PSEG Site 2.10.2.1 Floating Debris Spectrum There currently exists no known regulatory guidance on how to establish a floating debris spectrum for a storm surge event. In absence of any specific guidance, a review of the HCGS licensing and design basis was undertaken, as it considered floating missiles at a nuclear power plant. The current licensing basis for HCGS (Reference 2.10-9) references a probabilistic and deterministic evaluation of floating missiles impacting plant operation. A.D. Little (Reference Page 2-113
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.10-10) prepared an analysis of the likelihood of waterborne traffic and other floating objects on the Delaware River impacting HCGS in severe storms. Reference 2.10-10 includes the following primary objectives:
Developed a profile of floating objects and assessed their impacts on the overall integrity of the plant.
Profiled the marine traffic on the Delaware River and estimate the likely probability of impacting HCGS.
2.10.2.1.1 Floating Objects in the Site Vicinity With assistance from USACE and input from the Bechtel Design Guidelines for tornado missiles, Reference 2.10-10 developed a floating debris spectrum of potentially damaging missiles during floods and severe storms. At that time and still today, design criteria for environmentally damaging missiles had not been established by the NRC or any other federal agency. This historical floating debris spectrum represents, similar to the tornado missile spectra, objects that would typically be found around a power plant site. Since the PSEG Site is remotely located, surrounded primarily by marsh lands and the Delaware River, objects on the PSEG Site property were considered. A walkdown of the PSEG Site was completed to augment the list of types of floating debris considered at the time of HCGS licensing with any robust and potentially buoyant objects not considered to be enveloped by the historical floating debris spectrum. The resulting floating debris spectrum is presented in Table 2.10-3.
2.10.2.1.2 Marine Vessel Traffic The second portion Reference 2.10-10 develops a conservative analysis of the probability of marine vessel traffic in the Delaware River impacting the powerblock or intake structures.
Based on a conservative review of marine traffic, the potential for a runaway vessel, and the probability of the initiating event (a PMH storm occurring), the report concludes the probability of the service water intake structure being impacted by any vessel under the postulated storm conditions is 6.1 x 10-8. The probability of the HCGS powerblock being impacted by any vessel under the postulated storm conditions is 4.7 x 10-8. To assess the applicability of this analysis to current day conditions, the marine traffic levels considered in Reference 2.10-10 are reviewed against current day values.
Reference 2.10-10 provides marine traffic estimates for a given day. These values were recognized to be extremely conservative - both by the authors of Reference 2.10-10 and by the mariners and military officers who provided them at the time. The provided values were used to develop estimates of the risk that vessel traffic would present to HCGS during a severe storm.
The authors of Reference 2.10-10 made all their assumptions in a conservative manner to ensure that the final report was deemed to be a conservative overestimate of the likelihood of the events of concern. A comparison of the vessel traffic values observed during the last decade and the values used in Reference 2.10-10 show that the values in the Reference 2.10-10 are an order of magnitude higher than observed vessel traffic levels from 2004 to 2008 (Reference 2.10-16). This demonstrates the extremely conservative and enveloping nature of the vessel traffic levels considered in Reference 2.10-10.
Hurricane preparations described in Reference 2.10-10 consist of vessels going to sea, or those remaining in port using additional anchors, longer anchor chains, additional mooring lines and Page 2-114
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 bridge and standby engine room watches. No specific restrictions on anchorage were considered in Reference 2.10-10. Reference 2.10-10 assumes that 6 to 12 vessels will be in anchorages to the south of HCGS during a hurricane. In comparison, current day USCG hurricane preparation (Reference 2.10-12), restricts vessels from remaining at anchor above Big Stone Point less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to hurricane, and does not allow barges to anchor during a hurricane without USCG permission.
Based on the assessment of current day marine vessel traffic levels to those considered in Reference 2.10-10 and the increased hurricane preparations undertaken today by the USCG, the probability conclusions in Reference 2.10-10 are considered to remain applicable today.
Therefore, further consideration of the impact of large marine vessels is not required.
2.10.2.2 Waterborne Debris Impact Forces As with developing the debris spectrum for consideration at the PSEG Site, a lack of specific guidance exists in assessing the effects of floating debris impacts during a hurricane-induced storm surge event. Reference 2.10-17 recommends using a methodology for determining impact loads based on the momentum impulse method described in Reference 2.10-13.
Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers (ASCE) 7-10, provides requirements for general structural design and includes means for determining dead, live, soil, flood, snow, rain, atmospheric ice, earthquake, and wind loads, as well as their combinations, which are suitable for inclusion in building codes and other documents (Reference 2.10-13). ASCE 7-10, Section C5, specifically Equation C5-3 shown below, presents a methodology for determining impact loads for flood borne debris.
Equation 2.10-1 where:
F resulting force in lb W weight of the object in lb, taken from Table 2.10-3 Vb velocity of the object in fps (assumed equal to the velocity of water per Reference 2.10-13), taken as the maximum average current velocity perpendicular to the structure at each critical point around the PSEG Site, see Table 2.10-4 Ci importance coefficient, taken as 1.3 per Table C5-1 of Reference 2.10-13 CO orientation coefficient, taken as 0.8 per Reference 2.10-13 CD depth coefficient, taken as 1 per Table C5-2 of Reference 2.10-13 for a still water depth greater than 1.5 m (5 ft)
CB blockage coefficient, taken as 1 per Table C5-3 of Reference 2.10-13 Rmax maximum response ratio, conservatively taken as 1.8 per Table C5-4 of Reference 2.10-13 t impact duration, taken as 0.03 seconds per Reference 2.10-13 g acceleration due to gravity, 32.2 ft/s2 As described in Subsection 2.10.1, a set of storms was selected to bracket the 10-6 AEP still WSEL producing event for the site. The average of this set approximates the 10-6 AEP still WSEL and the storms include the broadest range of storm parameters possible. The ADCIRC+SWAN model velocity results for these six storms are used to determine debris loads Page 2-115
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 for the set of debris types presented in Table 2.10-3. Table 2.10-4 presents the maximum current velocity component normal to the structure adjacent to each of the locations for each storm event. The highest velocities are typically at points on the south side of facilities. The average of the maximum velocity component normal to the structure for the six storms is used in Equation 2.10-1. Table 2.10-5 presents the debris forces (in kips) for all locations and debris types. Table 2.10-6 includes the debris impact pressure (kips/ft2), distributing the force over the contact area defined in Table 2.10-3.
Waves have the ability to push debris into structures and it is recognized that the above methodology does not account for the effects of waves on waterborne debris. An established method developed by Dean and Dalrymple (Reference 2.10-14) presents a rigorously derived expression for the wave forces applied to a floating rectangular object, assuming the object is small relative to the wavelength of the applied waves. The Reference 2.10-14 methodology focuses on wave forces applied to a floating rectangular object, and it is assumed that forces applied by waves to an object are (or can be) carried by the debris directly into a wall or structure at the PSEG Site. This is clearly conservative, particularly for larger debris items, as the debris items will not respond as quickly as the water in the wave. The forces applied by the waves computed using the Dean and Dalrymple methodology are much less than the forces computed using the ASCE 7-10 methodology; therefore, the forces presented in Table 2.10-5 are considered the bounding debris forces during a storm surge event.
2.10.2.3 Conclusions The debris impact force and pressure values presented in Tables 2.10-5 and 2.10-6, respectively, represent a conservative assessment of the effect of debris in a hurricane-induced storm surge event. Due to the broad site-wide nature of the debris impact analysis at this stage of the flood hazard reevaluation project, this analysis does not consider the following location specific aspects of a more detailed debris impact analysis:
No consideration is given to the debris deforming. Further analysis will likely show the debris will deform at lower forces than the concrete wall or pressure tight doors, therefore reducing the actual loads imparted to the plant structures.
The floodwater velocities evaluated are the maximum values for each location, thereby conservatively assuming the debris is within the water current and at the impact location at the exact time the velocity peaks.
Further discussion of the comparison to the current design and licensing basis of the plant is provided in Subsection 3.10.2.
2.10.3 Erosion and Sedimentation As described in the preceding sections, the LIP and storm surge events are the controlling flood causing mechanisms for the PSEG Site. Therefore, the effect of erosion and sedimentation is considered for these events. The discussion of sedimentation and erosion due to the LIP event is discussed in Subsection 2.1.4.2 and concludes that the potential for erosion and deposition during the LIP event is low. Sedimentation and erosion during the storm surge event is discussed in Subsection 2.4.6. The storm surge event can cause resuspension of natural sediments in the Delaware Bay and lead to deposition on the order of 2 in. of material. Erosion potential around the critical safety related structures is low.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.10.4 Concurrent Site Conditions Site conditions at the PSEG Site for the critical flood causing mechanisms, LIP and storm surge, in both cases would be a concurrent severe storm event. As described in Section 1.5, the flood protection features at HCGS do not require operator action outside the flood protected Category 1 structures. The reevaluated flood causing mechanisms assessed do not introduce any other plausible storm event scenarios than those already considered at the PSEG Site.
2.10.5 Groundwater Ingress The groundwater analysis presented in the PSEG Site ESPA SSAR provides a recent assessment of the conditions around the PSEG Site. Per Subsection 2.4.12.1.2 of Reference 2.10-8:
The shallow soils of the PSEG Site consist of fill materials or spoils (hydraulic fill) historically dredged from the adjacent Delaware River. Beneath the hydraulic fill are alluvial deposits (riverbed sands, gravels, and clays). These alluvial deposits represent the original ground surface (which was submerged as the river bed in this area at the time the dredge spoils were initially placed) (Reference 2.4.12-29). The hydraulic fill and the alluvial sands and gravels also constitute the shallow groundwater flow system that overlies either the alluvial clay or the top of the Upper Kirkwood Formation (a clay-rich, semi-confining unit at approximately -39 ft. NAVD). The shallow aquifer is recharged directly by infiltration of precipitation where not impeded by buildings, pavement, or other stormwater diversion structures from the existing plants. The groundwater surface is typically encountered at depths ranging from 5 to 10 ft. bgs.
Comparison to the current licensing basis for the plant is discussed in Section 3.10.5.
2.10.6 Other Pertinent Factors The other pertinent factor for flood causing mechanisms at the PSEG Site is the flood event duration. Flood event duration is defined in Reference 2.10-2 as the length of time the flood event affects the site, beginning with conditions being met for entry into a flood procedure or notification of and impending flood (e.g., a flood forecast or notification of dam failure), including preparation for the flood and the period of inundation, and ending when water has completely receded from the site and the plant has reached a safe and stable state that can be maintained indefinitely. Each of these three aspects is described below for the two critical flood causing mechanisms, LIP and Storm Surge. Comparison to the current licensing basis for the plant is discussed in Section 3.10.6.
2.10.6.1 LIP Event Duration Site Preparation for Flood Event Closure of watertight doors will be required to mitigate the potential flooding effects of the LIP event. As discussed in Section 4.1, PSEG is undertaking an assessment of LIP trigger levels and predictive measures to inform operations staff to execute the door closure procedure ahead of a LIP event. This trigger will allow enough time for operations staff to close the doors, currently a one (SWIS) to 1.5 (power block) hour credited activity per Technical Specification Page 2-117
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 3/4.7.3 (Reference 2.10-15). After the watertight doors are closed, HCGS flood protection features have significant margin above the LIP WSELs evaluated in Section 2.1.
Period of Inundation The period of inundation for the LIP event defined as the duration in which floodwaters are above the floor elevation on which the door is located, is provided in Table 2.1-3 and is bounded by the inundation associated with the storm surge event, which is discussed in Subsection 2.10.6.2.
Recession of Water from the Site The recession of water from the site is considered in the values provided in Table 2.1-3.
2.10.6.2 Storm Surge Event Duration Site Preparation for Flood Event Site preparation prior to a severe weather event begins 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> before the potential onset of the event. A list of the trigger procedures and associated actions for providing flood protection and mitigation is summarized in Reference 2.10-7. Closure of watertight doors is the primary flood protection activity taken in the hours preceding the period of inundation. Watertight doors are required to be closed when severe storm warnings from the National Weather Service (NWS) which may impact Artificial Island are in effect or with the water level at SWIS above elevation 6.0 ft. msl (95.0 ft. PSD) per Technical Specification 3/4.7.3 (Reference 2.10-15).
The reevaluated storm surge hazard does not introduce any new limitations on the current site preparation for the flood event. The Technical Specification 3/4.7.3 watertight door closure time of 1 to 1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after a NWS severe storm warning is issued or the river level of 95.0 ft PSD is reached provides adequate time to close the watertight doors prior to the storm surge flood waters to encroach onto site grade.
Period of Inundation The period of inundation for the storm surge event is developed by assessing the six storm events discussed in Section 2.10.1 and determining the duration the storm surge WSEL exceeds site grade, nominally and conservatively taken as 9 ft. NAVD (98.8 ft. PSD). Results from the ADCIRC+SWAN simulations indicate the average period of inundation is 10.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> with a standard deviation of 1.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.
Recession of Water from the Site The recession of water from the site is considered in the values provided in the period of inundation duration. The storm surge simulations were run with sufficient duration to assure any effect of the surge water traveling back towards the site is not encountered. Therefore, once the surge water recedes during the period of inundation, activities outside the plants flood protected structures can proceed as required.
2.10.7 References 2.10-1 U.S. Nuclear Regulatory Commission, Trigger Conditions for Performing an Integrated Assessment and Due Date for Response, ML12326A912, December 3, 2012.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.10-2 U.S. Nuclear Regulatory Commission, Interim Staff Guidance for Performing the Integrated Assessment for External Flooding, JLD-ISG-12-05, Revision 0, November 30, 2012.
2.10-3 U.S. Nuclear Regulatory Commission, Interim Staff Guidance for Performing a Tsunami, Surge, or Seiche Hazard Assessment, JLD-ISG-12-06, January 2013.
2.10-4 U.S. Army Corps of Engineers, Coastal Engineering Manual, Engineer Manual 1110-2-1100, United States Army Corps of Engineers, Washington, D.C. (in 6 volumes), 2002.
2.10-5 Goda, Y. New Wave Pressure Formulae for Composite Breakwaters, Proceedings of the 14th International Coastal Engineering Conference Vol.3, pp.
1702-1720. 1974.
2.10-6 Tanimoto, K, K. Moto, S. Ishizuka, and Y. Goda. An Investigation on Design Wave Force formulae of Composite Breakwaters, Proceedings of the 23rd Japanese Conference on Coastal Engineering, pp 11-16. 1976.
2.10-7 PSEG Nuclear LLC, Hope Creek Generating Station Response to Recommendation 2.3: Flooding Walkdown of the Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident, Letter No. LR-N12-0369, dated November 26, 2012.
2.10.8 PSEG Power, LLC and PSEG Nuclear, LLC. PSEG Site Early Site Permit Application, Part 2, Rev.2, Subsection 2.4.12. 2013.
2.10-9 PSEG Nuclear LLC, Hope Creek Generating Station Updated Final Safety Analysis Report, Revision 19, 2012.
2.10-10 Arthur D. Little, Inc., An Analysis of the Likelihood of Waterborne Traffic and other Floating Objects on the Delaware River Impacting the Hope Creek Generating Station in Severe Storms, C-50918, September 1984.
2.10-11 Not Used.
2.10-12 U.S. Coast Guard, COTP Sector Delaware Bay Port Hurricane Contingency Plan, through Amendment Change No. 6, 2011.
2.10-13 American Society of Civil Engineers (ASCE) 7-10. Minimum Design Loads for Buildings and Other Structures. Second Printing.
2.10-14 Dean, R.G. and Dalrymple, R.A., Water Wave Mechanics for Engineers and Scientists, Prentice Hall, 353pp. 1991.
2.10-15 PSEG Nuclear LLC, Hope Creek Generating Station Technical Specifications, through Amendment 194, 2013.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 2.10-16 Rutgers University, Modeling and Analysis of the Vessel Traffic in the Delaware River and Bay Area: Risk Assessment and Mitigation, Report 204-RU6532, January 2012.
2.10-17 U.S. Nuclear Regulatory Commission, Guidance for Assessment of Flooding Hazards Due to Dam Failure, JLD-ISG-2013-01, Revision 0, July 29, 2013.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-1 Subset of Storm Events Selected for Final Analysis in the Wave and Debris Load Calculations Radius to Central Forward Still Storm Maximum Holland B Landfall Angle of Pressure Speed WSEL Number Winds Parameter Displacement Storm (millibars) (knots) (m)
(nm) 11 918 45 1.00 2.00 0.00 30 6.71 20 918 45 1.10 2.00 0.00 30 7.01 21 918 45 1.10 3.00 0.00 30 6.75 25 918 45 1.10 1.00 0.00 30 6.24 33 918 30 1.10 2.00 -22.50 30 6.28 60 918 30 1.10 2.00 -11.25 30 6.37 Page 2-121
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-2 Maximum Wave Loading for Six Storms and Calculated 10-6 Probability Loads Max Total Load for Each Storm (kips/ft) Average Total Location Load(b) 11 20 21 25 33 60 (kips/ft) 1 6.27 9.33 6.82 6.15 5.07 6.08 6.62 2 16.81 17.45 16.83 13.02 13.48 13.36 15.16 3 15.49 16.54 15.80 11.72 12.07 11.79 13.90 4 6.79 8.41 6.98 5.34 5.43 5.46 6.40 5 8.31 9.31 8.43 6.66 6.94 7.11 7.80 6 24.26 23.87 24.14 18.44 19.41 19.18 21.55 7 16.21 18.43 16.46 12.57 13.05 13.50 15.04 8 5.62 6.70 5.80 4.25 4.33 4.42 5.19 9 6.10 7.29 6.24 4.71 4.95 5.09 5.73 10 6.61 8.00 6.80 5.16 5.41 5.58 6.26 11 10.54 11.42 10.62 7.75 8.25 8.38 9.49 12 10.60 11.51 10.68 7.93 8.38 8.52 9.60 13 8.14 8.99 8.16 6.44 6.87 7.04 7.61 14 7.90 8.84 7.93 5.91 6.55 6.64 7.29 15 7.39 8.48 7.49 5.23 5.79 5.82 6.70 16 6.39 7.35 6.49 4.38 5.00 5.17 5.80 17 Not Applicable(a) 5.35 18 5.61 6.85 5.76 4.29 4.53 4.66 5.28 19 5.30 6.30 5.40 3.53 3.91 4.02 4.74 20 8.46 9.97 8.67 5.36 6.24 6.33 7.51 21 Not Applicable(a) 3.86 22 4.91 6.41 5.09 3.31 3.71 3.77 4.53 a) Hydrodynamic wave forces are not applicable at this location as wave action is blocked by the turbine building. Therefore, only the hydrostatic component of the total wave force is presented.
b) Total load includes hydrostatic forces and hydrodynamic wave loads.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-3 Waterborne Debris Spectra Tare Diameter Height Length Width Contact Weight Gross Debris Type (ft.) (ft.) (ft.) (ft.) Area(a) (ft2) (lb) Weight (lb) 1.Cryogenic Dewar 2.17 4.42 N/A N/A 3.7 300 1,700 2.Referigerant 2.50 4.78 N/A N/A 4.9 334 1,334 Recovery Tank 3.IBC Tank N/A 4.50 4.5 6.3 20.3 1,047 13,456 4.Bullet Resistant N/A 7.33 8 6 44.0 N/A 12,250 Enclosure
- 5. Intermodal Shipping Container, N/A 9.50 53 8.5 80.8 10,310 67,200 53'
- 6. Intermodal Shipping Container, N/A 9.50 45 8.5 80.8 10,910 74,960 45'
- 7. House N/A 10.0 20 10 50.0 N/A 4,000
- 8. Recreational Boat N/A 4.0 34 6 0.55 N/A 25,000
- 9. Automobile N/A 4.5 16.4 6.6 20.0 N/A 4,000
- 10. Telephone Pole 1.125 N/A 35 N/A 0.99 N/A 1,490 a) Contact area is defined as the smallest surface area of the object. Contact area for items 7 through 9 are from Reference 2.10-10.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-4 Maximum Impact Current Velocity at Each Location(b)
Max Impact Current Velocity for Each Storm (ft/sec) Average Velocity Location 11 20 21 25 33 60 (ft/sec) 1 0.31 0.45 0.44 0.56 0.59 0.49 0.48 2 0.12 0.22 0.17 0.15 0.33 0.22 0.20 3 2.88 2.77 2.81 2.48 2.44 2.46 2.64 4 0.67 3.26 0.62 0.77 0.58 0.61 1.09 5 0.09 1.05 0.00 0.82 0.44 0.99 0.57 6 0.89 0.80 0.85 0.72 0.73 0.90 0.82 7 2.82 2.78 2.79 2.07 2.11 2.29 2.48 8 2.26 2.62 2.26 1.51 1.74 2.59 2.16 9 0.39 0.33 0.36 0.36 0.40 0.39 0.37 10 0.45 0.39 0.42 0.29 0.36 0.35 0.38 11 0.18 0.12 0.14 0.16 0.17 0.13 0.15 12 0.18 0.12 0.14 0.16 0.17 0.13 0.15 13 0.18 0.12 0.14 0.16 0.17 0.13 0.15 14 0.42 0.38 0.42 0.31 0.26 0.37 0.36 15 0.47 0.48 0.45 0.38 0.41 0.40 0.43 16 3.39 3.62 3.26 2.70 3.00 2.90 3.15 17 Not Applicable(a) 18 1.31 1.16 1.25 0.99 1.07 1.03 1.13 19 0.00 0.00 0.00 0.15 0.00 0.00 0.03 20 0.34 0.37 0.34 0.26 0.28 0.27 0.31 21 Not Applicable(a) 22 0.34 0.30 0.33 0.38 0.30 0.32 0.33 a) Current velocity is not applicable at this location as it is interior to the building.
b) Maximum current impact velocity is the velocity component normal to the structure.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-5 Maximum Debris Force at Each Location Sheet 1 of 2 Maximum Debris Force (kips) at each Location Debris Type 1 2 3 4 5 6 7 8 9 10
- 1. Cryogenic Dewar Tare 0.43 0.18 2.41 0.99 0.52 0.75 2.26 1.98 0.34 0.34
- 2. Refrigerant Tare 0.48 0.20 2.69 1.10 0.57 0.83 2.52 2.20 0.38 0.38 Recovery Tank Gross 1.93 0.82 10.73 4.41 2.30 3.32 10.06 8.79 1.51 1.53
- 3. IBC Tank Tare 1.51 0.64 8.42 3.46 1.80 2.60 7.90 6.90 1.19 1.20
- 4. BRE (Elevated) Gross 17.72 7.51 98.52 40.49 21.08 30.45 92.38 80.74 13.88 14.01
- 5. Shipping Tare 14.92 6.32 82.92 34.08 17.74 25.62 77.75 67.95 11.68 11.79 Container, 53' Gross 97.23 41.19 540.47 222.11 115.65 167.02 506.74 442.91 76.12 76.88
- 6. Shipping Tare 15.78 6.69 87.75 36.06 18.78 27.12 82.27 71.91 12.36 12.48 Container, 45' Gross 108.45 45.95 602.88 247.76 129.01 186.31 565.26 494.06 84.91 85.75
- 7. Office Trailer Gross 5.79 2.45 32.17 13.22 6.88 9.94 30.16 26.36 4.53 4.58
- 8. Recreational Boat Gross 36.17 15.32 201.07 82.63 43.03 62.14 188.52 164.77 28.32 28.60
- 9. Automobile Gross 5.79 2.45 32.17 13.22 6.88 9.94 30.16 26.36 4.53 4.58
- 10. Telephone Pole Gross 2.16 0.91 11.98 4.92 2.56 3.70 11.24 9.82 1.69 1.70 Page 2-125
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-5 Maximum Debris Force at Each Location Sheet 2 of 2 Maximum Debris Force (kips) at each Location Debris Type 11 12 13 14 15 16 17 18 19 20 21 22
- 1. Cryogenic Dewar Tare 0.14 0.14 0.14 0.33 0.39 2.87 0 1.04 0.02 0.28 0 0.30
- 2. Referigerant Tare 0.15 0.15 0.15 0.37 0.44 3.20 0 1.15 0.03 0.31 0 0.34 Recovery Tank Gross 0.61 0.61 0.61 1.46 1.75 12.78 0 4.61 0.10 1.26 0 1.34
- 3. IBC Tank Tare 0.48 0.48 0.48 1.15 1.38 10.03 0 3.62 0.08 0.99 0 1.05
- 4. BRE (Elevated) Gross 5.63 5.63 5.63 13.41 16.12 117.38 0 42.33 0.94 11.55 0 12.30
- 5. Shipping Tare 4.74 4.74 4.74 11.29 13.56 98.79 0 35.63 0.79 9.72 0 10.35 Container, 53' Gross 30.88 30.88 30.88 73.59 88.40 643.93 0 232.23 5.15 63.34 0 67.48
- 6. Shipping Tare 5.01 5.01 5.01 11.95 14.35 104.54 0 37.70 0.84 10.28 0 10.95 Container, 45' Gross 34.45 34.45 34.45 82.08 98.61 718.28 0 259.05 5.74 70.65 0 75.27
- 7. Office Trailer Gross 1.84 1.84 1.84 4.38 5.26 38.33 0 13.82 0.31 3.77 0 4.02
- 8. Recreational Boat Gross 11.49 11.49 11.49 27.38 32.89 239.56 0 86.40 1.91 23.56 0 25.10
- 9. Automobile Gross 1.84 1.84 1.84 4.38 5.26 38.33 0 13.82 0.31 3.77 0 4.02
- 10. Telephone Pole Gross 0.68 0.68 0.68 1.63 1.96 14.28 0 5.15 0.11 1.40 0 1.50 Page 2-126
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-6 Maximum Debris Pressure at Each Location Sheet 1 of 2 Maximum Debris Pressure (kips/ft2) at each Location Debris Type 1 2 3 4 5 6 7 8 9 10
- 1. Cryogenic Dewar Tare 0.12 0.05 0.65 0.27 0.14 0.20 0.61 0.53 0.09 0.09
- 2. Refrigerant Tare 0.10 0.04 0.55 0.23 0.12 0.17 0.51 0.45 0.08 0.08 Recovery Tank Gross 0.39 0.17 2.19 0.90 0.47 0.68 2.05 1.79 0.31 0.31
- 3. IBC Tank Tare 0.07 0.03 0.41 0.17 0.09 0.13 0.39 0.34 0.06 0.06
- 4. BRE (Elevated) Gross 0.40 0.17 2.24 0.92 0.48 0.69 2.10 1.84 0.32 0.32
- 5. Shipping Tare 0.18 0.08 1.03 0.42 0.22 0.32 0.96 0.84 0.14 0.15 Container, 53' Gross 1.20 0.51 6.69 2.75 1.43 2.07 6.27 5.48 0.94 0.95
- 6. Shipping Tare 0.20 0.08 1.09 0.45 0.23 0.34 1.02 0.89 0.15 0.15 Container, 45' Gross 1.34 0.57 7.46 3.07 1.60 2.31 7.00 6.11 1.05 1.06
- 7. Office Trailer Gross 0.12 0.05 0.64 0.26 0.14 0.20 0.60 0.53 0.09 0.09
- 8. Recreational Boat Gross 65.77 27.86 365.60 150.25 78.23 112.98 342.78 299.61 51.49 52.00
- 9. Automobile Gross 0.29 0.12 1.61 0.66 0.34 0.50 1.51 1.32 0.23 0.23
- 10. Telephone Pole Gross 2.18 0.92 12.11 4.97 2.59 3.74 11.35 9.92 1.70 1.72 Page 2-127
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 2.10-6 Maximum Debris Pressure at Each Location Sheet 2 of 2 Maximum Debris Pressure (kips/ft2) at each Location Debris Type 11 12 13 14 15 16 17 18 19 20 21 22
- 1. Cryogenic Dewar Tare 0.04 0.04 0.04 0.09 0.11 0.78 0 0.28 0.01 0.08 0 0.08
- 2. Refrigerant Tare 0.03 0.03 0.03 0.07 0.09 0.65 0 0.24 0.01 0.06 0 0.07 Recovery Tank Gross 0.13 0.13 0.13 0.30 0.36 2.61 0 0.94 0.02 0.26 0 0.27
- 3. IBC Tank Tare 0.02 0.02 0.02 0.06 0.07 0.49 0 0.18 0.00 0.05 0 0.05
- 4. BRE (Elevated) Gross 0.13 0.13 0.13 0.30 0.37 2.67 0 0.96 0.02 0.26 0 0.28
- 5. Shipping Tare 0.06 0.06 0.06 0.14 0.17 1.22 0 0.44 0.01 0.12 0 0.13 Container, 53' Gross 0.38 0.38 0.38 0.91 1.09 7.97 0 2.87 0.06 0.78 0 0.84
- 6. Shipping Tare 0.06 0.06 0.06 0.15 0.18 1.29 0 0.47 0.01 0.13 0 0.14 Container, 45' Gross 0.43 0.43 0.43 1.02 1.22 8.89 0 3.21 0.07 0.87 0 0.93
- 7. Office Trailer Gross 0.04 0.04 0.04 0.09 0.11 0.77 0 0.28 0.01 0.08 0 0.08
- 8. Recreational Boat Gross 20.89 20.89 20.89 49.78 59.80 435.58 0 157.09 3.48 42.84 0 45.64
- 9. Automobile Gross 0.09 0.09 0.09 0.22 0.26 1.92 0 0.69 0.02 0.19 0 0.20
- 10. Telephone Pole Gross 0.69 0.69 0.69 1.65 1.98 14.42 0 5.20 0.12 1.42 0 1.51 Page 2-128
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Figure 2.10-1 Table VI-5-53 from USACE Coastal Engineering Manual Table VI-5-53 Goda F01lllula fot' Irregular Waves (Goda 1974; Tanimoto et al. 1976)
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h" ,,'I,tc'r tIt'pth ilt H cli:-.tann' (If 5/1 * ....i1wllttl of til" hrl'"kwal.'r fronl wall.
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Page 2-129 Sargent & Luncly\l~
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 3.0 COMPARISON OF CURRENT DESIGN BASIS AND FLOOD CAUSING MECHANISMS This section summarizes the comparison of current design basis flood elevations at various safety-related SSCs against corresponding reevaluated flood elevations from the same flood-causing mechanisms. Table 3-1 shows the comparison of flood elevations from all flood-causing mechanisms for the current and reevaluated design basis conditions. Table 3-1 indicates which of the reevaluated flood causing mechanisms are bounded by the current licensing basis flood hazard. The comparison shows that the reevaluated flood elevation due to the local intense precipitation (LIP) event exceeds the current design basis flood elevation at some of the critical water tight doors. Interim actions proposed are described in Chapter 4 of this report.
Page 3-1
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 3-1 Comparison of Current Licensing Basis Flood Elevations and Reevaluated Flood Causing Mechanisms CLB Still CLB Max Reevaluated Flooding Mechanism Critical SSC Water Height Flood Height Flood Level Bounded (ft. PSD) (ft. PSD) (ft. PSD)
Watertight Doors at SWIS Local Intense Precipitation 101.9 102.6 No and Powerblock Flooding in Streams and Powerblock/SWIS 97.3 109.8 104.2 Yes(a)
Rivers No Flooding Dam Breaches and Failures Site Grade 102.5 115.3 Yes Expected Powerblock 113.8 120.0/124.4 112.3/120.0 Yes Storm Surge SWIS 113.8 134.4 112.3/126.1 Yes No Flooding Seiche Site Grade No Flooding Expected Yes Expected No Flooding Tsunami Site Grade 95 107.1 Yes Expected No Flooding Ice Induced Flooding Site Grade No Flooding Expected Yes Expected Channel Migration or No Flooding Site Grade No Flooding Expected Yes Diversion Expected Combined Effects Powerblock/SWIS See Section 1.2.9 See Section 3.9 Yes Not specifically addressed in Associated Effects Powerblock/SWIS See Section 3.10 No the CLB a) See Section 3.2 for a discussion of this event.
Page 3-2
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 3.1 LOCAL INTENSE PRECIPITATION The HCGS UFSAR (Reference 3-1) indicates that the site drainage design allows storm water drainage away from the site and eliminates any flooding impact to the site. The plant area has a site grade elevation of approximately 11.7 ft NAVD or 101.5 ft. PSD. The watertight door locations at grade are nominally elevation 12.2 ft. NAVD or 102 ft. PSD.
The reevaluated flooding impacts due to the local intense precipitation are presented in Section 2.1. The reevaluation uses HMR 52 to obtain the point rainfall intensities and used the FLO-2D computer model to simulate peak runoff and corresponding maximum water levels at the critical door locations at the power block area. The analysis is performed assuming underground storm drains and culverts, as well as roof drains are clogged and not functioning during the LIP event.
The simulated peak water surface elevations (WSELs) in the power block area varied between 11.9 and 12.8 ft. NAVD (101.7 to 102.6 ft. PSD) resulting in a range of flooding water depths from 0.5 to 1.7 ft. above grade at the critical door locations. The simulated peak WSEL at the service water intake structure is 9.7 ft. NAVD (99.5 ft. PSD) resulting in a flood depth of 0.7 ft.
above grade and 2.5 ft. below the watertight door threshold. The simulated peak flow velocities varied between 0.6 feet per second (fps) to 0.9 fps, which are not expected to produce any erosion hazards as described in Section 2.1. Since the CLB WSEL of 101.9 ft. PSD is exceeded by the reevaluated LIP event WSEL, this event is not considered bounded by the CLB.
Proposed interim actions based on the results of this analysis are described in Chapter 4.
3.2 FLOODING IN STREAMS AND RIVERS The HCGS UFSAR (Reference 3-1) evaluated flooding in streams and rivers utilizing analysis results from a previous study for the Summit Generating Station Preliminary Safety Analysis Review to estimate PMF discharge on the Delaware River at the Chesapeake and Delaware Canal. The PMF was determined to be a relatively minor flooding event in comparison to other postulated events evaluated. Therefore, a simplified but conservative estimating approach for the CLB PMF levels at the HCGS was utilized. The CLB PMF still WSEL at HCGS was calculated to be 97.3 ft. PSD, with a total WSEL of 109.8 ft. PSD.
Reevaluation of flooding in streams and rivers, as discussed in Section 2.2, identifies a peak still WSEL of 14.4 ft. NAVD or 104.2 ft. PSD due to the combined effects of the probable maximum flood (PMF), 10% exceedance high tide and coincident storm surge. As discussed in Section 2.2, the tidal and storm surge components dominate the total WSEL established, with the flooding due to the half-PMF or full-PMF only producing a still WSEL of approximately 2 to 3 ft.
NAVD (91.8 to 92.8 ft. PSD) at the PSEG Site. The combined effects of storm surge and tide are analyzed in detail in Section 2.4, and the relatively low WSEL at the PSEG Site associated with the PMF, HCGS is not adversely impacted from hazards associated with flooding in streams and rivers. Since the CLB PMF still WSEL of 97.3 ft. PSD exceeds the reevaluated PMF WSEL, this event is considered bounded by the CLB.
3.3 DAM FAILURE The HCGS UFSAR (Reference 3-1) considers flooding due to dam failure. The HCGS CLB dam breach flood hazard analysis considered the both single and cascading dam failure events. The CLB worst case scenario (postulated multiple failures of Cannonsville, Pepacton, and Tocks Page 3-3
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Island Dams) analysis resulted in a still WSEL of 12.7 ft. NAVD (102.5 ft. PSD) at HCGS. The CLB maximum wave runup elevation was estimated to be 25.5 ft. NAVD (115.3 ft. PSD).
Reevaluation of flooding due to dam failure in accordance with current regulatory guidance (Reference 3-2), as discussed in Section 2.3, concludes there are no critical dams in the watershed above the PSEG Site. Therefore, HCGS is not adversely impacted from hazards associated with flooding due to dam failure. Since the CLB dam failure still WSEL exceeds the reevaluated dam failure WSEL, this event is considered bounded by the CLB.
3.4 STORM SURGE The HCGS UFSAR (Reference 3-1) evaluation of flooding due to storm surge indicates this is the design basis flood event for the site. Section 1.2.4 describes the CLB storm surge evaluation methodology and concludes the maximum still WSEL of 113.8 ft. PSD (with tidal effects), and total WSELs of 120.0 to 124.4 ft. PSD at the powerblock and 134.4 ft. PSD at the service water intake structure are calculated with wave runup. Doors and penetrations in exterior walls of the HCGS Auxiliary and Reactor Buildings are protected against water inflow up to elevation 127 ft. PSD for parts of the south exterior walls and up to elevation 121 ft. PSD of other exterior walls. Penetrations in exterior walls and slabs of the SSWS intake structure are protected against water inflow up to elevation 121 ft. PSD for the north and east exterior walls and up to elevation 128.5 ft. PSD for other exterior walls and slabs.
Using the Joint Probability Method with Optimal Sampling (JPM-OS) developed by USACE, the reevaluated 10-6 annual exceedance probability still WSEL is established at 112.3 ft. PSD, including the potential future effects of sea level rise. Table 3-2 presents a comparison of storm surge still and total WSELs between the CLB and reevaluated storm surge event. The reevaluated storm surge wave runup values are bounded by the CLB calculated values at all safety related structures around the plant. Since the CLB storm surge total WSEL is greater than the reevaluated storm surge total WSEL, this event is considered bounded by the CLB.
Associated effects of the storm surge flooding event are further discussed in Section 3.10.
3.5 SEICHE The HCGS UFSAR (Reference 3-1) analysis of flooding due to seiche concludes seiche is not a viable flood causing mechanism on the Delaware Estuary. Reevaluation of flooding due to seiche, as discussed in Section 2.5, concludes there is no plausible mechanism where a seiche could cause flooding at the PSEG Site. Therefore, HCGS is not adversely impacted from hazards associated with flooding due to seiche. Since neither the CLB or the reevaluated assessment considers flooding from a seiche event to be a flood hazard for HCGS, this event is considered bounded by the CLB.
3.6 TSUNAMI The HCGS UFSAR (Reference 3-1) includes and evaluation of flooding due to a tsunami, as discussed in Section 1.2.6. The CLB still WSEL at HCGS resulting from tsunami waves is 5.2 ft.
NAVD (95 ft. PSD). The total WSEL including a coincident wave height with a 2-year extreme wind associated with the tsunami wave height and 10 percent exceedance high tide is 17.3 ft.
NAVD (107.1 ft. PSD).
Page 3-4
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Reevaluation of flooding due to a tsunami, as discussed in Section 2.6, concludes the peak WSEL of 5.7 ft. NAVD at PSEG Site due to a combination of the 10% exceedance high tide (4.5 ft. NAVD) and tsunami effects. When compared to site grade, conservatively taken as 9 ft.
NAVD, HCGS is not adversely impacted from hazards associated with flooding due to a tsunami. Since the CLB tsunami still WSEL exceeds the reevaluated tsunami WSEL, this event is considered bounded by the CLB.
3.7 ICE INDUCED FLOODING The HCGS UFSAR (Reference 3-1) concludes the potential for flooding due to an ice jam is negligible, but does indicate surface ice is possible. Reevaluation of flooding due to an upstream ice jam failure, as discussed in Section 2.7. The resulting 8.1 ft. NAVD WSEL at the PSEG Site, is due to the combination of the 10 percent exceedance high tide (4.5 ft. NAVD), the spring base flows (0.7 ft.), the rise in the Delaware River resulting from the upstream ice jam breach at Trenton (0.1 ft.), and the coincident wave runup from a 2-year wind speed applied in the critical direction (2.8 ft.). When compared to site grade, conservatively taken as 9 ft. NAVD, HCGS is not adversely impacted from hazards associated with flooding due to an upstream ice jam break. Since neither the CLB or the reevaluated assessment considers flooding from an ice jam event to be a flood hazard for HCGS, this event is considered bounded by the CLB.
3.8 CHANNEL MIGRATION OR DIVERSION The HCGS UFSAR (Reference 3-1) does not evaluate flooding due to channel migration or diversion, indicating no channel diversions needs to be considered in the Delaware Estuary.
The potential for channel diversions caused by landslide, mudslide, or other temporary diversion of flow either directly upstream or downstream of the PSEG Site is highly unlikely due to the shallow nature of the lower Delaware River and the flat topography near the PSEG Site.
Therefore, HCGS is not adversely impacted from hazards associated with flooding due to channel migration and diversion. Since neither the CLB or the reevaluated assessment considers flooding from an channel migration or diversion to be a flood hazard for HCGS, this event is considered bounded by the CLB.
3.9 COMBINED EFFECTS Combined effects of different flood causing mechanisms are discussed in Sections 3.1 through 3.8, where applicable. The combined effects of wave run-up, tides and river discharge are considered in the reevaluation of the storm surge hazard. The total WSEL at critical locations around the plant structures, as discussed in Section 2.4 and 3.4, are bounded by the existing CLB at all safety related structures.
3.10 ASSOCIATED EFFECTS An assessment of flood height and associated effects is required as discussed in Reference 3-3. The phrase flood height and associated effects is defined in the Reference 3-4 as the maximum stillwater surface elevation plus the following factors; wind waves and run-up effects; hydrodynamic loading, including debris; effects caused by sediment deposition and erosion; concurrent site conditions, including adverse weather conditions; groundwater ingress; and Page 3-5
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 other pertinent factors. Analysis of wind waves and run-up effects is discussed in Section 2.9; comparison of the remaining items is provided below.
3.10.1 Hydrostatic and Hydrodynamic Loads The current licensing basis for HCGS (Reference 3-1) includes evaluation of the effects of hydrostatic and hydrodynamic loads on all critical safety related structures. A comparison of the loading combinations evaluated in the current design basis versus the loads developed in Section 2.10.1 is presented in Table 3-3. As can be seen in the table, in all cases the reevaluated total loads are less than the loads used in analyzing the critical safety related structures. Therefore, the reevaluated total hydrostatic and hydrodynamic loads are considered bounded by the CLB.
Per HCGS UFSAR Section 3.4.1.1, "All exterior doors in Seismic Category I structures are designed to withstand the static and dynamic effects from postulated floods and the associated wave action. External watertight doors can withstand the same wave loading combinations the respective walls experience, and as discussed above, the reevaluated loads are lower than the CLB load combinations.
HCGS is not adversely impacted from any combined hydrostatic and hydrodynamic loads of the reevaluated flooding hazard.
3.10.2 Debris Loads The current licensing basis for HCGS (Reference 3-1) references probabilistic evaluation of floating missiles impacting plant operation. A.D. Little (Reference 1-15) prepared an analysis of the likelihood of waterborne traffic and other floating objects on the Delaware River impacting HCGS in severe storms, which is further discussed in Subsection 1.2.10.2. As discussed in Subsection 2.10.2, the reevaluated hazard from the effects of waterborne debris impacts include potential debris spectra based on typical current day site conditions, the velocity at which the waterborne debris could impact safety-related SSC, and a conservative evaluation of the forces and pressures the debris could impart on a structure or component.
Impact of debris in a flooded environment could lead to the failure of a flood protection feature and a potential leakage pathway into the flood protected areas of the plant. The primary flood protection features above grade on the exterior of the Category I plant structures are the concrete walls of the buildings and watertight doors.
For the concrete walls of flood protected Category I structures, the primary design criteria with respect to externally generated impact loads is related to tornado missiles. Per Subsection 3.5.3 of Reference 3-1, concrete elements subject to tornado missile impact are in general not less than 24 in. thick for walls and 18 in. thick for roofs, except for the roof of the Auxiliary Building radwaste/service area, and the portion of the roof of the plant cancelled area within the cylinder wall. This wall thickness has been analyzed as sufficient to withstand the impact from any tornado missiles. To assess the capability of a typical Category 1 concrete wall to withstand the effects of a waterborne debris impact, a comparison of the kinetic energy per unit area of the tornado missile spectra with the waterborne debris spectra developed in Subsection 2.10.2 is developed. Table 3-4 presents the kinetic energy of the tornado missiles using Equation 3.10-1 and the missile spectra from Table 3.5-12 of Reference 3-1. Table 3-5 Page 3-6
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 presents the kinetic energy of the waterborne debris using the same equation and information developed in Subsection 2.10.2.
KE = 1/2 mv2 Equation 3.10-1 where m mass in slugs v velocity in fps The maximum kinetic energy and kinetic energy per unit area values associated with the tornado missile spectra are much greater than those of the waterborne debris spectra. Both the tornado missile spectra and the waterborne debris spectra are expected to behave similarly when impacting a 24 in. thick concrete wall. The debris will likely absorb much of the energy while deforming against the concrete structure. Based on this comparison, waterborne debris impacts are not considered to adversely impact the reinforced concrete walls associated with Category I flood protected structures, and the reevaluated hazard is bounded by the CLB.
The other structures for consideration of debris impact are the watertight doors, typically located at grade level. The current design basis calculation analyzes the watertight doors due to the effects of floating missile impact by considering the energy absorption capability of the doors.
The watertight doors are first evaluated considering energy balance method for collision of two bodies. By equating the kinetic energy of the floating missile to the kinetic energy absorbed by plastic deformation of the door, a ductility ratio was determined based on the plastic deformation (deflection) of the door. The acceptance criteria for maximum allowable ductility ratio are based on two deflection requirements. First by limiting the allowable deflection to maintain structural integrity of the door, a ductility ratio of 10 is used. Second to maintain leak tightness of the door, the maximum ductility ratio was reduced to limit plastic deflection. The allowable ductility ratio for leak tightness varies per watertight door type.
Based on the methodology described above, to evaluate the structural capability of the watertight doors a comparison of kinetic energy and kinetic energy per unit area is made between the existing design basis calculation floating missiles and the waterborne debris spectra developed in Subsection 2.10.2. Table 3-5 presents the kinetic energy of the waterborne debris using Equation 2.10-1 and information developed in Subsection 2.10.2.
Table 3-6 presents the kinetic energy of the waterborne debris using Equation 2.10-1 and information from the existing design basis calculation. The maximum kinetic energy and kinetic energy per unit values associated with the existing floating missile spectra are much greater than those of the flood hazard reevaluation waterborne debris spectra due to the conservative velocities used in the current design basis calculation. Therefore, the effect of debris impact on watertight doors based on the reevaluated flood hazard is bounded by the CLB.
HCGS is not adversely impacted from the effects of debris impact during any reevaluated flooding hazard event.
3.10.3 Erosion and Sedimentation The current licensing basis for HCGS (Reference 3-1) does not include evaluation of the effects of erosion and sedimentation on critical safety related structures. As discussed in Subsection 2.10.3, the reevaluated hazard from erosion and sedimentation during the LIP and storm surge Page 3-7
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 events is considered minimal and will not have an adverse effect on the plant. Therefore, HCGS is not adversely impacted from erosion and sedimentation related to any reevaluated flooding hazard, and the reevaluated hazard is considered bounded by the CLB.
3.10.4 Concurrent Site Conditions The current licensing basis for HCGS (Reference 3-1) does not specifically discuss evaluation of concurrent site conditions, such as storm conditions during the event. However, as discussed in Section 1.5, the flood protection features for HCGS do not require operator action outside of flood protected structures concurrent with the severe storm event. All outside actions (e.g., traveling to the service water intake structure and closing watertight doors) take place prior to the onset of the inundation portion of the flood event. Therefore, HCGS is not adversely impacted by concurrent site conditions related to any reevaluated flooding hazard, and the reevaluated hazard is considered bounded by the CLB.
3.10.5 Groundwater Ingress The current licensing basis for HCGS (Reference 3-1) indicates the maximum expected water table elevation is conservatively taken as 96 ft. PSD for foundation analysis. Below grade structures at HCGS are designed to mitigate the effects of the continuous presence of groundwater through the use of waterproofing and waterstops. As discussed in Section 2.10.5, groundwater is typically encountered around the PSEG Site at 5 to 10 ft. below grade surface or nominally 92 ft. PSD. Therefore, HCGS is not adversely impacted by groundwater ingress related to any reevaluated flooding hazard, and the reevaluated hazard is considered bounded by the CLB.
3.10.6 Other Pertinent Factors As discussed in Section 2.10.6, flood duration is the other pertinent factor in the assessment of the reevaluated flood hazard. Reference 3-4 has defined flood duration as the total time comprising the preparations for a flood event, the period of inundation and the recession of flood waters from the site. The flood protection features at HCGS are design as permanent features and therefore, are not affected by the period of inundation and recession of flood waters from the site. The preparation for a severe weather event is covered both administratively via procedure and through Technical Specification Action Statements at HCGS.
Local Intense Precipitation No trigger currently exists to close the watertight doors prior to a LIP event. Watertight door closure is currently triggered on river level in both the severe weather procedure (Reference 3-
- 7) and the Technical Specifications (Reference 3-8). As discussed in Section 2.1, the WSEL during a LIP event at some of the critical door locations exceeds the watertight door threshold in less than one hour, faster than the one and a half hours currently credited to facilitate watertight door closure in the Technical Specifications. Therefore, this aspect of the flood hazard is not considered bounded by the CLB, and interim actions based on the results of this assessment are proposed in Chapter 4.
Storm Surge Watertight door closure is currently triggered on river level in both the severe weather procedure (Reference 3-7) and the Technical Specifications (Reference 3-8). Door closure is initiated Page 3-8
PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 when river level is expected to reach 95 ft. PSD in accordance with Reference 3-7 and door closure initiation is required by Reference 3-8 at river level 95 ft. PSD or with a NWS severe storm warning affecting the site. Based on these actions, sufficient time exists to assure the active flood protection features are in place prior to the onset of the storm surge event.
Therefore, this aspect of the flood hazard is bounded by the CLB and HCGS is not adversely impacted by the duration of the storm surge event.
3.11 CONCLUSIONS The comparisons between the CLB WSELs and the reevaluated flood hazard WSELs conclude the safety related structures at HCGS are protected from all flood causing mechanisms once the flood protection features are in place (i.e., watertight doors closed). However, as discussed above, the LIP event WSEL and site preparation duration time exceeds the CLB; therefore, interim actions and an integrated assessment of this event is required.
3.12 REFERENCES 3-1 PSEG Nuclear LLC, Hope Creek Generating Station Updated Final Safety Analysis Report, Revision 19, 2012.
3-2 U.S. Nuclear Regulatory Commission, Interim Staff Guidance for Estimating Flooding Hazards due to Dam Failure, JLD-ISG-2013-01, July 29, 2013.
3-3 U.S. Nuclear Regulatory Commission, Trigger Conditions for Performing an Integrated Assessment and Due Date for Response, ML12326A912, December 3, 2012.
3-4 U.S. Nuclear Regulatory Commission, Interim Staff Guidance for Performing the Integrated Assessment for External Flooding, JLD-ISG-2012-05, November 30, 2012.
3-5 Not Used.
3-6 PSEG Nuclear LLC, Severe Weather and Natural Disaster Guidelines, Procedure OP-AA-108-111-1001, Revision 9, 2013.
3-7 PSEG Nuclear LLC, Acts of Nature, Procedure HC.OP-AB.MISC-0001 (Q), Revision 23, 2013.
3-8 PSEG Nuclear LLC, Hope Creek Generating Station Technical Specifications, through Amendment 194, 2013.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 3-2 Comparison of Storm Surge Water Surface Elevations (b)
HCGS UFSAR Storm Surge Flood Height Values Reevaluated Storm Surge Max.
Max. Flood Corresponding Flood Structure Wall Height(d) Location Number Height (a)
(ft. PSD) (see Figure 2.4-4)
(ft. PSD)
South 120.0(c) 20 120.0 South Unit 1 Reactor (Between 20' to 120' west of turbine 124.4 20 120.0 Building building)
West 120.0 19 116.3 Auxiliary Building West 120.0 19 116.3 Diesel Generator North 120.0 22 116.7 Auxiliary Building South 120.0 20 120.0 Radwaste South (20' west of turbine building) 124.4 20 119.5 Plant Cancelled North 120.0 22 116.7 Area (Unit 2) West 120.0 19 116.3 East 120.0 4 116.5 North 120.0 1 114.2 SWIS South 134.4 3 126.1 West 134.4 2 121.8 a) The maximum flood height WSEL includes consideration of potential sea level rise.
b) HCGS UFSAR storm surge flood height values are from Reference 3-1.
c) The maximum flood height value for the south wall of the reactor building is from Fetch 2 on Table 2.4-10 of Reference 3-1.
d) The maximum flood height value at the power block for areas other than the wall between 20 ft. and 120 ft. west of the turbine building are conservatively set to the wave runup value associated with Fetch 2 on Table 2.4-10 of Reference 3-1.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 3-3 Comparison of Storm Surge Wave Loading (a)
CLB PMH Loads Revaluated Total Loads Design Wave Force (kips/ft)
Corresponding Total Load(b)
Building Wall Static Load Dynamic Load Total Location Number (kips/ft)
(see Figure 2.4-4)
East 7.00 39.80 46.80 21 3.86 North 7.00 39.80 46.80 22 4.53 Power Block South 7.00 39.80 46.80 20 7.51 West 7.00 39.80 46.80 19 4.74 East 7.00 39.80 46.80 4 6.40 North 2.00 8.60 10.60 1 6.62 SWIS South 13.50 77.00 90.50 3 13.90 West 53.80 27.60 81.40 2 15.16 a) HCGS UFSAR storm surge loads are from Table 2.4-11a of Reference 3-1.
b) Total load combines the hydrostatic and hydrodynamic component.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 3-4 Tornado Missile Kinetic Energy (a)
Contact Velocity Weight Mass KE No. Description Area(b) KE/ft2 (fps) (lb) (slug) (ft-lb)
(ft2) 1 Wood plank 0.29 272.3 114.6 3.56 132,068 451,419 2 6 in Schedule 40 Pipe 0.24 170.6 286.6 8.91 129,644 541,538 3 1-in steel rod 0.01 167.3 8.8 0.27 3828 701,905 4 Utility pole 0.99 180.4 1124.4 34.95 568,739 572,172 5 12 in Schedule 40 Pipe 0.87 154.2 749.6 23.30 277,024 319,926 6 Automobile 28.03 193.6 3990.4 124.04 2,324,588 82,937 Maximum 2,324,588 701,905 a) Tornado missile characteristics are from Table 3.5-12 of Reference 3-1.
b) Contact area is defined as the smallest surface area of the object, based on the characteristics provided in Table 3.5-12 of Reference 3-1.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 3-5 Waterborne Debris Kinetic Energy(b)
Contact Velocity Weight Mass KE No. Description KE/ft2 Area (ft2) (fps) (a) (lb) (slug) (ft-lb) 1 Cryogenic Dewar 3.70 4 1700 52.84 423 114 2 Referigerant Recovery Tank 4.90 4 1334 41.47 332 68 3 IBC Tank 20.30 4 13456 418.28 3346 165 4 Bullet Resistant Enclosure 44.00 4 12250 380.79 3046 69 5 Intermodal Shipping Container, 53' 80.80 4 67200 2088.90 16,711 207 6 Intermodal Shipping Container, 45' 80.80 4 74960 2330.12 18,641 231 7 House 50.00 4 4000 124.34 995 20 8 Recreational Boat 0.55 4 25000 777.12 6217 11,304 9 Automobile 20.00 4 4000 124.34 995 50 10 Telephone Pole 0.99 4 1490 46.32 371 374 Maximum 18,641 11,304 a) A conservative velocity of 4 fps is considered in the assessment of waterborne debris kinetic energy. This exceeds all the maximum impact current velocity values reported on Table 2.10-4.
b) Contact area and weight are defined in Table 2.10-3.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 Table 3-6 Current Design Basis Waterborne Debris Kinetic Energy (a)
Contact Velocity Weight Mass KE No. Description KE/ft2 Area (ft2) (fps) (lb) (slug) (ft-lb) 1 House 50.00 29.33 4000 124.34 53,494 1070 2 Recreational Boat 0.55 29.33 25,000 777.12 334,335 607,882 3 Automobile 20.00 29.33 4000 124.34 53,494 2675 4 Telephone Pole 0.99 29.33 1490 46.32 19,926 20,128 Maximum 334,335 607,882 a) Waterborne debris characteristics are from HCGS design basis documents.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 4.0 INTERIM EVALUATION AND ACTIONS TAKEN OR PLANNED 4.1 LOCAL INTENSE PRECIPITATION A storm capable of producing the amount of rainfall resulting in the LIP event would be expected to be predicted with at least 24-hour notice. OP-AA-108-111-1001 (Reference 4-1) and HC.OP-AB.MISC-0001 (Reference 4-2) will require revision to align current actions to the LIP event.
The specific revision elements have not been determined at this time. However, when completed they will provide sufficient notice to preemptively implement the flood protection features currently in place without being overly prescriptive.
As discussed in Section 2.1, the reevaluated LIP event could produce flood levels (102.6 ft.
PSD) that are above watertight door thresholds, but significantly below the plants flood protected elevation described in Section 1.5. Plant safety can be ensured by implementing operating procedure HC.OP-AB.MISC-0001 (Reference 4-2), which instructs operators to close all watertight doors. The advance notice needed prior to implementing the watertight door closure in HC.OP-AB.MISC-0001 is 1 to 1.5 hrs; however, the meteorological conditions that produce a LIP event (high-intensity, short-duration) are such that a determination of reasonable advanced notice is warranted.
Interim actions are proposed to assist in determining the advanced notice needed and provide recommendations for revising operating procedures OP-AA-108-111-1001 and HC.OP-AB.MISC-0001. These proposed interim actions include:
determine the threshold (i.e., minimum) LIP event that could produce flood levels above critical watertight door locations, identify the type of storms that produce a LIP event, and determine the best source (e.g., National Weather Service) for a set of parameters for use in initiating watertight door closure.
The goal of these proposed interim actions is to integrate severe weather forecast guidance into action level guidance to be used in procedures OP-AA-108-111-1001 and HC.OP-AB.MISC-0001. The parameters will provide adequate response time to enact the mitigative actions required, while not be overly conservative so as to warrant actions to be prescribed unnecessarily. The response time will also allow mitigative actions to be performed prior to the onset of the LIP event.
4.2 REFERENCES
4-1 PSEG Nuclear LLC, Severe Weather and Natural Disaster Guidelines, Procedure OP-AA-108-111-1001, Revision 9, 2013.
4-2 PSEG Nuclear LLC, Acts of Nature, Procedure HC.OP-AB.MISC-0001(Q), Revision 23, 2013.
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PSEG Nuclear LLC SL-012271 Hope Creek Generating Station Revision 0 Flood Hazard Reevaluation Project No.: 12800-213 5.0 ADDITIONAL ACTIONS Flood hazard reevaluations are being performed in two phases. In Phase 1 of the 50.54(f) letter process, flood hazards are reevaluated using present-day regulatory guidance and methodologies applicable to new plant applications. If the reevaluated hazard is not bounded by the design basis flood at the site, licensees must perform an integrated assessment for external flooding. During Phase 2 of the 50.54(f) letter process, NRC staff will use the Phase 1 results to determine whether additional regulatory actions are required. HCGS will perform an integrated assessment in accordance with JLD- ISG-2012-05, Guidance for Performing an Integrated Assessment for Flooding (Reference 5-1).
5.1 REFERENCES
5-1 U.S. Nuclear Regulatory Commission, Guidance for Performing the Integrated Assessment for External Flooding, JLD-ISG-2012-05, Revision 0, November 2012.
Page 5-1