ML19308D868
| ML19308D868 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 07/13/1973 |
| From: | Rodgers J FLORIDA POWER CORP. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19308D862 | List: |
| References | |
| NUDOCS 8003191075 | |
| Download: ML19308D868 (5) | |
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Florida July 13, 1973
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The Director
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United States Atomic Energy i
Commission Washington, DC 20545 3
If IN RE: FLORIDA POWER CORPORATION CRYSTAL RIVER NUCLEAR GENERATING PLANT DOCKET No. 50-302
Dear Sir:
Enclosed are seventy (70) copies of the following documents:
1.
Dames & Moore Report, July 13, 1973, Report Verification Study of Dames & Moore's Hurricane Storm Surge Model With Application To Crystal River Unit 3 Nuclear Plant, Crystal River, Florida, For Florida Power Corporation.
2.
Gilbert Associates, Inc., Report No. 1807, July 11, 1973, Hurricane Study, Crystal River Unit No. 3 Nuclear Plant.
Amendment No. 28, which will be filed on August 1,1973, consists
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of revised FSAR pages which constitute our response to the Request for j
Additional Information made in Mr. R. C. DeYoung's letter of March 12, 1973. The documents mentioned above are being provided to facilitate J
your staff's review of Amendment No. 28, since they are referenced therein.
In addition, we are enclosing seventy (70) copies of our response to the Request for Additional Information made in Mr. R. C. DeYoung's letter of March 12, 1973, in " question and answer" format to facilitate your review.
Please contact us if you require any discussion or clarification of the above information.
Very truly yours,
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J. T. Rodgers Assistant Vice President JTR/nu 56S1 Enclosures 800319107 General Office 320i inuty #ourtn street soutn. P O. Box 14042. St Petersburg. Florca 33733 e 813-866 5151
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ENCLOSURES (1) AND (2)
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ENCLOSURE (1)
Question 1 To consider your model further, we will require a complete mathematical and theoretical description of the model.
Response
The model is based on the general equations of horizontal fluid flow; simplified to neglect certain second-order terms and to be quasi-one dimensional in nature. The model is designed to analyze the open coast storm surge due to the passage of an idealized Probable Maximum Hurricane (PNH). A complete mathematical and theoretical description of the model can be found in Section 2 and Appendix B of the Dames & Moore, Report -
Verification Study of Dames & Moore's Hurricane Storm Surge Model with Application to Crystal River Unit No. 3 Nuclear Plant, Crystal River, Florida. For Florida Power Corporation, dated July 13, 1973.
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- athD 1W The Director ci SUG natul([
Directorate of Licensing J
United States Atomic Energy Commission Y.ywsf Washington, D. C. 20545 W
Dear Sir:
0 In Re: Florida Power Corporation Crystal River Nuclear Generating Plant Docket No. 50-302 Enclosed are three (3) originals and nineteen (19) conformed copies of Amendment No. 28 to the Application for Licenses for Crystal River Unit 3 Nuclear Gene-rating Plant. Also enclosed are an additional eighty-one (81) copies for a total of 103 copies as previously furnished for your distribution.
Amendment No. 28 consists of revised pages to the Final Safety Analysis Report and Supplement No. 1 contained therein.
Specifically, these revisions contain responses to all the questions of the Request for Additional Information made in Mr. R. C. DeYoung's letter of March 12, 1973.
In our efforts to be responsive to the concerns expressed by the staff, we have met several times to exchange information concerning the probable maximum hurri-cane (PMH) with various staff personnel. Prior to this submittal, the enclosed information was reviewed via a visual presentation format at the Crystal River Plant Site with members of your staff arid their consultants.
The design presented to them and confirmed in Amendment No. 28 represents an adequately conservative one to assure safety during the PMH occurience which the AEC has proposed to'us.
Please contact us if you require any discussion or clarification of the above information.
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Very truly yours, G
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ads 1 General Office 32oi TNrty fourtn street soutn. P.O. Box 14042. St. Petersburg. Flonda 33733 e 81J -866-5151
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e Question 2 To consider your model further, we will require your basis for the selection of significant input parameters and a discussion of their degree of conservatism including bottom stress coefficients, wind stress coefficients and any other calibration coefficients.
Response
The parameters which define the intensity of a PMH such as: Central Pressure Inde::, Asymptotic Pressure, Radius to Maximum Winds, Forward Trans1ctional Speed and Maximum Wind Speed are found in the Hydrometeorological Memorandum HUR 7-97 published in May,1968. Both Dames & Moore and the AEC consultant use this reference to obtain these PHH parameters, and therefore obtain the same degree of conservatism. The coefficients which define wind stress and bottom friction in the Dames & Moore model have been calibrated with information for five hurricanes of record. These results are reported in Sections 2.2, 4.4 and 6.4.2 of Report - Verification Study of Dames & Moore's Hurricane Storm Surne Model with Application to Crystal River Unit No. 3 Nuclear Plant. Crystal River. Florida. For Florida Power Corporation. A bottom friction coefficient of 0.003 was used for Crystal River, which is the same value as used by the AEC's consultatt, CERC.
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x Question 3 To consider your model further, we will require a comprehensive verification of the model and its parameters by a comparison with the recorded surge hydro-graphs and peak water levels using recorded wind field and pressure data for at least the following storms:
1.
Hurricane Carla (1961) - Surge hydrographs at Galveston and Freeport, Texas.
2.
The October 3, 1949 hurricane surge hydrographs at Galveston and Freeport, Texas.
3.
Hurricane Ione (1955) - at a location north of where the storm crossed the East Coast.
4.
Hurricane Camille (1969) - peak water level on the Gulf Coast.
Response
A comprehensive verification of the Dames & Moore mathematical model and its parameters is covered in the Report - Verification Study of Dames & Moore's Hurricane Storm Surge Model with Application to Crystal River Unit No. 3 Nuclear Plant. Crystal River. Florida. For Florida Power Corporation. The verification of the model was accomplished by statistically comparing the calculated surge hydrographs with the recorded surge hydrographs for various storms supplied by the Atomic Energy Commission. Hydrographs were calculated using wind field and pressure data for the following storms:
1.
Hurricane Carla (1961) - Surge hydrographs at Galveston and Sabine Pass, Texas. Sabine Pass had been substituted for Freeport, Texas by the AEC's suggestion. A complete description of the data used and results obtained for this hurricane are reported in Sections 4. 3.2.1, 4. 3. 2.2, 4. 4. 7.1, 4. 4. 7.2, 4. 4.8, and 4.4.9 of the verification study mentioned previously.
2.
The October 3, 1949 hurricane with a surge hydrograph at Freeport, Texas. The hydrograph at Galveston, Texas was not used because the wind field data supplied by the AEC was not applicable to this station. The data used and the results obtained from the study for this hurricane are reported in Sections 4.3.3, 4.4.7.4, 4.4.8 and 4.4.9 of the previously mentioned verification study.
3.
Hurricane Audrey (1957) with a surge hydrograph at Eugene Island, Louisiana. The data used and the results obtained for this hurricane are reported in Sections 4.3.3, 4.4.7.3, 4.4.8 and 4.4.9 of the previously mentioned verificatica study..
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Hurricane Ione (1955) was not used in this verification study because no surge hydrograph data was supplied by the AEC for this hurricane.
Instead, Hurricane Carol (1954) was used.
5.
Hurricane Carol (1954) with a surge hydrograph at Newport, Rhode Island. The data used and the results obtained for this hurricane are reported in Sections 4. 3.5, 4. 4. 7.5, 4.4.8 and 4.4.9 of the previously mentioned verification study.-
6.
Hurricane Camille (1969) with peak water level for Biloxi, Mississippi. The data used and the results obtained for this hurricane are reported in Sections 4.3.6 and 4.4.10 of the previously mentioned verification study.
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Question 4 To consider your model further, we will require an explanation and analysis of the principle differences between your maximum surge for Crystal River and the staff's estimate.
Response
The Dames & Moore mathematical model is identical to that used by the AEC's consultant insofar as the form of the general equations defining horizontal fluid flow and the associated assumptions which define the validity of the horizontal flow equatione. Also, identical in the two models are the means of determining the input wind field and the range of the input values for the bottom friction factor. There are, however, two primary differences in the models: the wind stress factor and the numerics used in solving the general equations of horizontal fluid flow. These differences and their resolutions are the main subjects of the Dames & Moore study Report - Verifi-cation Study of Dames & Moore's HLrricane Storm Surge Model with Application to Crystal River Unit No. 3 Nuclear Plant, Crystal River Florida, For Florida Power Corporation. A detailed discussion of these differences can be found in Sections 2.2.3 and 6.1 of this report.
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s Question 5 We disagree with the basic application of your model to the P E surge level and, therefore, the coincident wind wave activity at the site. The follow-ing are the areas of disagreement, or areas for which insufficient information has been provided, and for which either a revised estimate or substantiation of your position should be provided.
Question 5(a)
The ambient tide conditions, during which a PE is assumed include both a high spring tide, and what is generally termed an initial rise. The initial rise is considered to be a sea level anomaly and is estimated by comparing recorded and preducted tides. Based on several years of record at local Gulf Coast tide stations, an initial rise of 0.6 feet should be assumed for the site. This condition is not considered a function of meteorological factors which could cause a PE, such as indicated on page 7 of your Appendix 2C, but rather to other causes as are generally observed in tide records. Provide a revised surge estimate including the above consideration.
Response
Since there is insufficient data to conclusively document whether or not an initial surge value attributed to non-pressure and non-wind effects should be included, a value of 0.6 foot initial surge was used in the calculation of a PE surge level for the Crystal River Unit No. 3 Nuclear Plant at Crystal River, Florida.
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Question 5(b)
Hurricane wind speed adjustments, when the storm is approaching closely to shore, are discussed in Memorandum HUR 7-97 (which was prepared by the Hydrometeorological Branch of the Weather Bureau, now National Oceanic and Atmospheric Administration) and your Appendix 2C.
However, surface wind speed reductions at two miles offshore would produce more conservative surge estimates than would the selected three mile value and should be included in a revised surge estimate.
If reference can be made, however, to doctamented evidence that wind speed reductions can be assumed further effshore, this less conservative assumption would be acceptable.
Response
According to the Hydrometeorological Memorandum HUR 7-97, the computed overwater wind should be adjusted when moving onshore. In using Table III of HUR 7-97, the overwater wind field should be reduced from full value two to three miles offshore to.89 of the value at the shoreline. Hugo Goodyear, an author of HUR 7-97, confirmed that this consideration applied to the Crystal River area. To be conservative, the overwater wind field was reduced from full value at two miles offshore to.89 of the value at the shoreline.
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Question 5(c)
No water surface frictional estimates are presented. Based on the U.S. Army Coastal Engineering Research Center Publication, Technical Memorandum No. 35, however, it has been found that surface friction should be assumed to vary with wind speed. Your assumptions should be presented, and if different than the referenced publication, they should be substantiated.
Response
It has previously been mentioned that the major difference in the utilization of Dames & Moore's mathematical model and that used by CERC involves the form used for the wind stress coefficient. The form of this coefficient as used in Dames & Moore's program has been demonstrated and documented in the Report - Verification Study of Dames & Moore's Hurricane Storm Surge Model with Application to Crystal River Unit 3 Nuclear Plant. Crystal River. Florida, For Florida Power Corporation, to be:
[CSK1 + CSK2 (1-U /U) ] (1.17P/29.92) k
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P is the barometric pressure, inches Hg U, is taken to be 15 mph U is the wind velocity in mph CSK1 and CSK2 are constants and k is independent of U, if U is less than or equal to Uo.
The values of the coefficients CSK1 and CSK2 were determined by correlating the output of Dames & Moore's program to storm surge hydro-graphs of record. These hydrographs were produced by the hurricanes of record mentioned in Response 3.
It was determined in the above mentioned report that good correlation to the data for these hurriccnes of record Oas obtained, using Dames & Moore's storm CSK1=1.0X10-6andCSK2=1.4X10gurgeprogram,withthevalues A detailed discussion of this correlation is - reported in the previously mentioned study in Sections 2.2.4, 5 and 6.4.2 (Section 12).
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Question 5(d)
For each safety-related structure, system, and component identified as necessary for plant protection (see Request 2.16 in Enclosure (2)), and based 4
on both a stillwater level of 33.4 feet MLW and your fully verified still-water elevation estimate, provide tabulations cf the height of the most significant (average of the highest one-third) and the maximum (1 percent) waves, or the breaking waves (whichever is the most severe) and the associated runup for each case.
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Response
The stillwater level, vind-generated wave height, breaking wa re height, and the wave runup corresponding to the fully verified 29.4 foot PMH stillwater level (Dames and Moore study, Report - Verification Study of Dames and Moore's Hurricane Storm Surge Model with Application to Crystal River Unit No. 3 Nuclear Power Plant - Crystal River Florida - for Florida Power Corporation, dated July 13, 1973) are shown in Figure 6 of the Gilbert Associates, Inc.
Report No.1807 Crystal River Unit No. 3 Hurricane Study, dated July 11, 1973 hereinaf ter referenced as the GAI Report. The maximtm (highest 1 percent of the waves) and significant (highest one-third) wave heights were determined by wind vectors normal to the coast, along the traverse, and were calculated using the storm surge computer output.
The intersection of the breaking wave curve and the generated wave height curves show that with the highest 1 percent of the waves breaking, the maximum height of the waves that can travel across the fill approaching the plant is 15.0 feet. With the average of the highest 33 percent of the waves breaking, the maximum height of the waves that can reach the protective embankment with-out breaking is 13.9 feet.
The effects of breaking waves and wave runup on the embankment slope were determined from model testing conducted in a wave tank at the University of Florida.
Unlike the spectrum of wind-generated waves, the model tests were conducted with waves of essentially uniform height. The embankment profile giving the results shown in Figure 3 corresponds to the stepped slope that will be constructed at Crystal River Nuclear Station.
The elevation of the water overtopping the elevation 118.5 embankment will be somewhat less than the elevation of the runup on the test slope because with a limited slope height (the steps above 118.5 used in the model do not exist in the actual design) the surging water will reach elevation 118.5 and merely fall over on the embankment.
The curves of maximum and median runup shown on Figure 6 of the GAI Report were developed from the indicated stillwater levels using Figure 3.
When the
- height of the wind-generated waves reaching the protective embankment becomes 10 to 15 feet (the range of wave heights found from the model tests to cause the ' greatest runup), the results of the model tests become applicable. Until that time, the wind-generated waves would produce less runup than indicated; -
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the runup is therefore shown as a dotted line. Employing the conservative assumption that the wave height in the model tests was the " maximum" generated wave height (i.e., assuming that all of the waves attacking the embankment are " maximum" waves), Figure 6 shows that the model results becomes applicable at 23.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> af ter the center of the hurricane crosses the continental shelf.
This is also the time of maximum stillwater level.
Overtopping of the embankment by the maximum runup begins about hour 22.7 and continues until hour 24.2.
In this 1.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> period, the maximum depth of stillwater at the safety class structures nearest the edge of the embankment ( a distance of about 100 feet) due to overtopping, is estimated to be one foot. At locations along the plant embankment that are not exposed to direct wave attack, overtopping should not occur. Water that does over-top the embankmant on the windward side of the plant will drain off the embankment on the lee side.
In response to the 33.4 foot surge level condition, refer to Section 9.0, PROTECTION AGAINST A SURGE LEVEL OF 33.4 FEET, of the GAI Report, dated July 11, 1973. Under this condition, where heights and associated runups are specifically addressed in Subsection 9.1 of the GAI Report.
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Question 5(e)
Discuss the applicability of your hydraulic model studies for estimating runup on and over ~ the soil-cement protected embankment and on interior facilities for both water levels and wave conditions discussed herein.
Response
The approach path of wave trains that will produce maximum runup at the site is along a north-south section with the waves approaching the plant from the south.
This critical path of approach was duplicated in a wave tank model for Unit No. 3 using existing topography, where applicable, and final grading and construction contours and facilities.
Wave tests using the criteria developed for the PMH tidal conditions were conducted by the Department of Coastal and Oceanographic Engineering of the University of Florida to determine the extent of wave runup on the protective embankment along the south side of the plant.
Since the model (Figure 1 of GAI Report No.1807) accurately represents the characteristics of topography, structures, and the protective embankment, the test results include the local effects unique to this site which are not reflected in generalized analytical relationships, but which increase in importance as the waves approach the plant.
Before performing the runup tests, experiments were conducted to cetermine the most adverse test conditions (i.e., the combination of wave period and height which caused the maximum runup over the tidal range of interest).
From these pre-test experiments and periodic checks during the tests, it was found that the maximt= runup occurred with a prototype wave period of 5.4 seconds, and prototype wave amplitudes of 10 to 15 feet, the specific height depending on the test case.
The wave action testing was conducted at proto-type tide levels from elevation 104 to 120 feet in two-foot increments.
Initial tests were conducted on a smooth slope embankment.
simulated the runup effects against the stepped embankment. Subsequent tests The tests results indicated no overtopping of the smooth slope below tide levels of 110 feet with occasional overtopping starting at a tide level of 112 feet and becoming continuous above elevation 114. Tests on the stepped slope revealed no over-topping below tide elevation 112 feet, sligh overtopping at 114, and more continuous overtopping above elevation 116 feet.
Pertinent results of the model tests are shown on Figures 2 and 3 and on Tables 1, 2, and 3.
The applicability of the model tests for the increased surge levels is further illustrated by Figure 3 and two letters from Dr. R. G. Dean dated April 3,1972, and April 11, 1973, contained in the Attachments to GAI Report No.1807.
indicated by Figure 3, the median and maximum runup elevations occurring at a As tide level of 117.4 feet are 122.5 and 123.5, respectively on Profile 5, the final design slope.
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