ML20010A729
| ML20010A729 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 08/06/1981 |
| From: | Linder F DAIRYLAND POWER COOPERATIVE |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-02, TASK-3-2, TASK-RR LAC-7738, NUDOCS 8108120117 | |
| Download: ML20010A729 (9) | |
Text
,
D DAiRYLAND h
COOPERAT/'E
- Po BOX 81/
- 2615 EAST AV SOUTH
- LA CROSSE. WISCONSIN 54601 (608) 788-4000 August 6, I')81 In reply, please refer to LAC-7738 DOCKET NO. 50-409 U. S. Nuclear Regulatory Commission l
ATTN:
Mr. Darrell G. Eisenhut, Director Division of Licensing dI ib Office of Nuclear Reactor Regulation 51U.
.U a
~
Division of Operating Reactors
/\\UG 1119P1 >
Washington, D. C.
20555 7b.,#* W.T # dh
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SUBJECT:
DAIRYLAND POWER COOPERATIVE LA CROSSE BOILING WATER REACTOR (LACBWR)
' 1.d
^/g PROVISIONAL OPERATING LICENSE NO. DPR-45 SEP TOPIC III WIND AND TORNADO LOACINGS
Reference:
(1)
DPC Letter, LAC-7387, Linder to Eisenhut, dated February 27, 1981.
Gentlemen:
Enclosed find Safety Evaluation Report (SER) for Wind and Tornado Loadings (SEP Topic III-2) which we have prepared for the La Crosse Boiling Water Reactor.
Our letter, Reference 1, identified topics for DPC to submit for NRC evaluation.
The subject topics were listed in the schedule submitted with Reference 1.
If there are any questions regarding this report, please contact us.
Very tru~y yours, DAIRYLAND POWER COOPERATIVE
/W Frank Linder, General Manager FD:FL:af cc:
J.
G.
Keppler, Director, NRC-DRO III NRC Resident Inspectors b
dYI if8 I 8108120117 8108 66 PDR ADOCK 05000409 P
L o
LA CROSSE BOILING WATER REACTOR SYSTEMATIC EVALUATION PROGRAM SAFETY EVALUATION REPORT TOPIC III-2 J
f WIND AND TORNADO LOADINGS I.
INTRODUCTION The safety objective of this review is to assure that structures, systems and components identified in Regulatory Guide 1.117 are adequately designed for wir.d loading, tornado wind loading, tornado pressure drop loading and that any damage to structures which are not designed for such loadings will not endanger the ability to nlace and maintcin the plant in a safe shutdown condition.
Tornado effects on emergency cooling ponds are also reviewed to assure that tornado winds will not prevent the cooling ponds from serving as a heat sink.
II. REVIEW CRITERIA The currently accepted design criteria for wind and tornado loadings on structures is outlined-in.the Standard Review Plan (SRP) Section 3.3.1 and Section 3.3.2 and in Regulatory Guides 1.76 and 1.117.
Tornado wind load is the governing wind load.
Regulatory Guide 1.76 specifies a maximum wind spced of 360 MPH and a pressure drop of 3 PSI at a rate of 2 PSI per second as the design basis tornado for the region in which LACBWR is located.
Reference 1 forwarded & site specific analysis of 4
tornado and straight wind hazards for LACBWR.
This site specific analysis provided a detailed probability distribution including "Mean Recurrence Interval" and " Hazard Probability" for various windspeeds.
Based on criteria included in Section 2.2.3 of the Standard Review Plan, the results of Reference 1 indicate a design basis tornado with a probability of 10-7 per year and expected windspeeds of 300 MPH or a design basis tornado with a probability of 10-6 per year and expected windspeeds of 237 MPH.
o Blow out panels are not used at this. plant to mitigate differ-ential pressure.
LACBWR uses the Mississippi River as a heat sink, therefore, concerns regarding the effect of tornadoes on emergency cooling ponds are not applicable to LACBWR.
l 1-I
III.
EVALUATION The La Crosse Boiling Water Reactor was built prior to the establishment of tornado loading criteria.
Wind loading, tornado wind loading, and tornado pressure drop loading were i
not considered in the original design of the La Crosse Bojling Water Reactor.
According to data included with Table 3-10 of the LACBWR Safeguards Report, the highest wind of record in 5
i the La Crosse area is 69 MPH in October 1949.
Section 3.4.4,6 of the LACBWR Safeguards Report, Reference 3, states that the La Crosse area reported approximately 10. tornadoes in a 50-i mile square from 1920 to 1949.
This led to the conclusion in the Safeguards Report that in the La Crosse area, there is an annual probability of 1/2000 that a tornado will affect a given square mile and that the chance that.a tornado will pass directly over the reactor site is even smaller.
The Reactor Containment Building was designed to withstand an internal pressure of 52 PSIG and a negative pressure of 0.5 PSIG.
Two vacuum breakers are set to start opening at a neg-ative pressure of app oximately 0.2 PSIG and to be fully open prior to reaching 0.5 PSIG negative pressure.
Original design calculations for the Containment Building also included a wind pressure of 20 lb/fta.
The Turbine Building was designed to withstand 25 lb/ft2 2
negative pressure and 25 lb/ft positive
- pressure, i
Subsequent wind and tornado analyses for major plant structures were performed in 1974 as part of the LACBWR Application fcr a Full-Term Operating License forwarded to the AEC by Beforence 4.
Structures analyzed included the LACBWR stack, the Genoa 3 stack, the Reactor Containment Building, the Waste Disposal Building, the Turbine Building and the Control Room.
Calculations of I
tornado wind loading and pressure drop loading were based on a tornado wind velocity of 300 MPH.
The following conclusions were stated in Section 1.3.2 of the LACBWR Application for a Full-Term Operating License:
(1)
The LACBWR chimney can withstand wind velocities up to 224 MPH without overturning at any section.
(2)
The Genoa #3 chemney can withstand wind velocities up to 235 MPH without overturning at any section.
o (3)
The analysis of the reactor containment building indicates that there is no danger due to external wind forces, or internal or external pressure differentials.
The cylindrical shell and concrete liner will not be perforated by missiles resulting
4 from a tornado.
However, the upper hemispherical head may be perforated by a small missile or a very large missile.
(4)
In general, the walls of the buildings investi-gated - the waste disposal building, the turbine building, and the control room - will be able to withstand the effect of missiles and differential air pressures occurring during a tornado.
An exception is the walls of the turbine building above 668 feet elevation.
The roofs, except for the control room, may be lifted off by air pressure, and in all cases the roofs may be perforated by falling sections of the LACBWR chimney.
It should be noted that air locks set for less than approxi-mately 3 PSI may be opened and natch covers leading to the pipe tunnel may be lifted off as indicated in Reference 1.
(5)
Because of the possibility of stock overturning and missile penetrations during a torn 0do, adequate administrative procedures are required to place the l
plant in a safe condition prior to the event.
l l
The analyses and plant design information forming the basis for the conclusions in Section 1.3.2 of the LACBWR Application for a Full-Term
{
Operating License have been reviewed.
It has been determined that further analysis will have to be performed on the west wall of the Control Room which is constructed of masonry and on the north walls of the Control Room, Electrical Equipment Room, and Machine Shop which are constructed of insulated metal paneling.
The 1B Diesel Generator Building was designed for a Maximum Windspeed of 111 MPH, a Rotational Speed of 83 MPH, a Translational Spaed of 28 MPH, a Radius of Maximum Rotational Speed of 100 feet, a Pressure Drop of 0.25 PSI ar.d a Rate of Pressure Drop of 0.08 PSI /SEC.
The Crib House is constructed of insulated metal paneling and has not been analyzed for tornado loading, but loss of the Crib House due to fire or a seismic event has been considered and it has been determined that the plant can achiave and maintain cold shutdown after loss of the Crib House.
It should be noted that the Advisory Commi'. tee on Reactor Safe-guards recommended the establishment of procedures for use in the event of a tornado warning in its letter to the Atomic Energy Commission dated November 17, 1966, Reference 1.
Heference 2, dated January 1967, stated that tornado alert procedures had been established.
In addition, required actions during a tornado warning were included as paragraph 4.1.5 of LACBWR Technical Specifications.
The current Tornado Warning procedure is included in Section 3.3.4 of the LACBWR Operating Manual, Volume I.
Plant Operators have several sources of weather information _ _ - _ - _ _ _ - _ _ _ _ - _ _ _ - _ _ - _ _ _ _ _ _ _ _ _ _ _ - _
at their disposal, including a NAWAS phone system and a NOAA weather radio in the Shift Supervidor's Office.
Plant personnel maintain frequent visual checks for the development, arrival, and passage of a severe storm.
Upon notification of a tornado warning for an area endangering the LACBWR site, the warning area will be plotted on charts maintained in the Control Room.
In the event a tornado is reported within 10 miles of the plant and the plant site is in the path of the storm, plant electrical load will be reduced to 20 MWe and the plant will be shut down if deemed necessary to ensure plant safety and integrity. to Reference 5, " Tornado and Straight Wind Hazard Probability for La Crosse Nuclear Power Reactor Site" included the following summary of tornado hazard probabilities:
TORNADO HAZARD PROBABILITIES WITH 95 PERCENT CONFIDENCE LIMITS l'EAN HAZARD TORNADO WINDSPEEDS, MPH RECU1RENCE PROBABILITY Fi7ECTED LOWER UPPER INT 1RVAL PER YEAR VALUE LIMIT LIMIT
~4 10,000 1.0 x 10 93 61 132
-5 100,000 1.0 x 10 174 146 215
-6 1,000,000 1.0 x 10 237 200 283
-7 10,000,000 1.0 x 10 300 261 364 Straight windspeed probabilities were calculated from historical data at Madison, Wisconsin, which is more severe than historical data at La Crosse.
Based on results cf the tornado hazard analysis, the following summary of windspeed hazard probabilities for La Crosse was derived:
o >
a
SUMMARY
OF WINDSPEED HAZARD PROBABILITIES FOR LA CROSSE MEAN EXPECTED RECURRENCE HAZARD WINDSPEED INTERVAL PROBABILITY MPH TYPE OF STORM
-1 10 1.0 x 10 70 Straight Wind
-2 100 1.0 x 10 91 Straight Wind
-3 1,000 1.0 x 10 111 Straight Wind
-4 10,000 1.0 x 10 131 Straight Wind
-5 100,000 1.0 x 10 174 Tornado
-6 1,000,000 1.0 x 10 237 Tornado 10,000,U00 1.0 x 10 300 Tornado Tornado analyses supporting the conclusions in the LACBWR Application for a Ful2-Term Op3 rating Licence used a windspeed of 300 MPH which is the Expected Windspeed of a tornado with a Mean Recurrence Interval of 10,000,000 years and a Hazard Probability Per Year of 1 x 10-7 I
At the 95 percent confidence upper limit, a tornads with a windspeed of 300 MPH has a Menn Recurrence Interval between 1,000,000 years and 10,000,000 and 1 x 10 years and a Hazard Probability Per Year between 1 x 10-5 The most limiting case of tornado damage would be the possible failure of the LACBWR stack 'or the possible failure of the Genoa #3 stack.
The probability that collapse of the stacks due to a tornado would lead to potential consequences in excess of 10 CFR Part 100 is reduced by the following factors:
(1)
There are conservatisms in the site specific analysis forwarded by Rtference 5 including the elimination of an curlying data point.
(2)
There is a substantial probability that even in the event of a tornado induced failure of the LACBWR o
stack or the Genoa #3 stack, there would be no sig-nificant impact on safety related structures.
A large section of the 350 foot tall LACBWR stack would have to fall within an arc of approximately 90*
to be of safety cor.eern due to possible damage to the Containment Building, the Control Room, or the Turbine - _ _ _ _ _ _ _ _ _ _ _ - _ _
Building.
Parts of the LACBWR stack would have to fall within another arc of approximately 70' to damage the Waste Treatment Building.
A large section of the 500 foot tall Genoa #3 stack would have to fall within an arc of approximately 30* at a distance of 400 to 500 feet from the base of the stack to be of safety concern due to possible damage to the Turbine Building, the Control Room, the Containment Building, the Waste Treatment Building, or the 1B Diesel Generator Building.
(3)
Calculations of the potential for stack penetration of the containment Building and the Control Room are based on very conservative assumptions of stack failure mode.
(4)
In the event that a stack does. penetrate the Containment Building or the Turbine Building, there is a substantial probability that no significant damage will occur to t
safety-related systems due to the location of safety-related equipment and the protection provided by the massive internal structures of the Containment Building and the Turbine Building.
In the Containment Building, the Fuel Element Storage Well and Shutdown Condenser might be damaged but the reactor vessel and recirculation piping are protected by a concrete plug.
The Turbine i
Building above the Turbine Floor at the 668' level is constructed of insulated metal panel walls and a precast concrete panel roof.
Equipment on the Turbine Floor is vulnerable to damage from tornado wind loading and collapse of the LACBWR stack or Gevca #3 stack, but I
there is no safety-related equipme.,t located on the-Terbine Floor.
Safety related equipment in the Turbine Building is located on the Mezzanine Floor and the Grade Floor where it is protected by reinforced concrete walls with a thickness of 12 inches or more and.the Turbine Floor and Mezzanine Floor which are 8 inch rein-forced concrete on heavy steel frame except the center section around the Turbine Pedestal which is reinforced concrete.
(5)
In the event safety-related systems were damaged, it is likely that radioactive releases could be limited or prevented by back-up systems and operator action.
IV.
CONCLUSION:
In conducting reviews for the preparation of this SER, we have determined that the information in Section 1.3.2 of the LACBWR Application for a Full-Term Operating License is incomplete.
It has been determined that the building walls discussed in this paragraph are reinforced concrete, concrete block, or a combination of the two including insulated exterior paneling.
The Control Room ceiling and south and east walls are reinforced concrete.
The west wall is concrete block and the north wall is insulated metal paneling with some 3/8" Astrolcy steel plates fastened to metal girts on the inside.
The limiting wind velocities reci/ed for the LACBWR and G-3 stacks are being re-examined.
There is a poscibility that earlier assumptions were less conservative than required and that additional calculations are needed.
Specifically in this regard, preliminary estimates indicate that the foundation of the G-3 stack and the section of the stack section approximately one-third of the distance from the top are likely to fail due to a seismic event before the stack base fails.
Evaluating these areas with respect to wind-induced pressure loads produces an estimate that failure of the G-3 stack could be expected at wind speeds in the range of 100-150 mph.
Altbough the LACBWR stack has not yet undergone a complete seismic analysis, similar considerativns apply to this structure.
Maximum windspeed for this stack can also be expected to be in the range of 100-150 mph.
These preliminary conclusions will be further investigated and verified.
In view of the observed possible, departures from Review Plan and Regulatory Guide Criteria justification for cont.irued operation of LACBWR is provided by the arguments presented above including the fact that the frequency of occurrence of late summer severe storms capable of generating high winds or in this geographical area tornadoes, is greatly reduced.
We are proaxding with further technical evaluative actions on this question on a priority basis.
o _--
REFERENCES 1.
ACRS Letter, Okrent to Seaborg, dated November 17, 1966.
2.
Amendment No. 31 to Construction Authorization CAPR-5, ACNP-67501, January 1967.
3.
"La Crosse Boiling Water Reactor Eafeguards Report",
ACNP-65544, August 1967.
4.
DPC Letter, LAC-2788, Madgett to Giambusso, dated October 9, 1974.
5.
NRC Letter, Crutchfield to Linder, dated December 15, 1980.
6.
Standard Review Plan (SRP) Section 2.2.3,
" Evaluation of Pc.ential Accidents",
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