ML20030C023
| ML20030C023 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 06/26/1981 |
| From: | Linder F DAIRYLAND POWER COOPERATIVE |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| TASK-02-03.C, TASK-2-3.C, TASK-RR LAC-7631, NUDOCS 8108250316 | |
| Download: ML20030C023 (9) | |
Text
D DA/RYLAND h
k COOPERAT/W eo so< e17 reiseAsTwso$T-1 ^ coast E mscov>Ne m,
t6CS 7834030 June 26, 1981 In reply, please refer to LAC-7631
,9' I ?!) m ) 'ET NO. 50 t109 U. S. Nuclear Regulatory Commission
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ATTN:
Mr. Darrell G. Eisenhut, Director 3-Q,4 go Division of Licensing Office of Nuclear Reactor Regulation Y
U Division of Operating Reactors
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.J Washington, D. C.
20555
SUBJECT:
DAIRYT AND POWER COOPERATIVE LA CROSSE BOILING WATER REACTOR (LACBWR)
SEP TOPIC II.3.C SAFETY RELATED WATER SUPPLY (ULTIMATE HEAT SINK - UHS)
REFERENCE:
(1)
DPC Letter, LAC-7387, Linder to Eisenhut, dated February 27, 1981.
Gentlemen:
Enclosed find the Safety Evaluation Report (SER) for Safety Related Water Supply (Ultimate Heat Sink - UHS) (SEP-II.3.C) 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 letter, please contact us.
Very truly yours, DAIRYLAND POWER C00 PERATIVE 17dl4/ h Adnt L Frank Linder, General Manager l
JDP:TL:ee jFOW cc:
J. G. Keppler, Reg. Dir., NRC-DRO III
,5 NRC Resident Inspectors
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0108250316 810626 PDR ADOCK 05000409 P
LA CROSSE BOILING WATER REACTOR SYSTEMATIC EVALUATION PROGRAM SAFETY EVALUATION REPORT TOPIC II.3.C SAFETY RELATED WATER SUPPLY TULTIMATE HEAT SINK - UHS)
The safety objective of this topic is to assure that the ultimate ~
heat sink provides an adequate source of water for facility oper-ation and, should it be necessary, for post accident cooling.
The ultimate heat sink of the La Crosse Boiling Water Reactor (LACBWR) is the Mississippi River.
The low flows in the Mississippi river at the site are subject to a certain amount of control and regulation by the 11 navigation dans on the river above the site and by several power reservoirs on the river and its tributaries.
However, the basic low-flow discharge pattern has not been altered, the effect of the regulation being largely transitory and of small influence on average monthly flows.
Low flow at the site occurs in the fall and winter; the lowest monthly average flow is most frequently recorded in February.
In periods of drought, minimum flows have also occurred in August and September.I The following tabulation of minimum and average flows is based on records collected by the U.
S. Geolocical Survey at the La Crosse, Wisconsin gagina station, 1930-1955.I FLOW DATE DISCHARGE, CFS Minumum daily December 30, 31, 1933 3,200 Median of annual 8,100 minimum daily Average monthly 9,000 exceeded in 95 percent of months 27,970 Average Low flows at the site will vary orig a; lightly from those at La Crosse.1 The minimum daily flow of N 300C cf, OD December 30, 31, 1933, remains the historic minimum as of 10?t,
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Regulatory Guide 1.27, Revision 2,
" Ultimate Heat Sink for Nuclear Power Plants", specifies an ultimate heat sink capable of providing sufficient cooling for at least 30 days to permit safe shutdown, cooldown and naintenance in a safe shutdown condition.
The normal maximum operating heat rejection water loads of LACBWR are 143 cfs, which is less than 5% of the historic low flow.
This water usage is condenser circulating water and service water.
As the plant demineralized water system make-up is drawn from well water, the service water is essentially a non-consumptive use.
In the cool-down process, these cooling requirements decrease.
The most signifi-cant usage of water in an off-normal situation would be the use of alternate core spray (an ECC System).
The alternate core spray would add a consumptive usage of 2 cfs.
The total usage requirement of decay heat removal and alternate core spray would be substantially less than the 143 cfs.
The need for information to substantiate the cooling method from other similar installations is not required in this case as LACBWR is a facility with 14 operating years of experience.
The reliability of the Mississippi River as the single ultimate heat sink is well documented in review of the historical low flow reported.
Therefore, an extremely low probability of losing the capacity of that source exists and a second source is not required.
The crib house (pumping station) was designed to the uniform Building Code 1958 edition which includes the site in Zone 0.
In February of 1981, an emergency service water system was installed which utilizes portable pumps.
If the crib house would become unavailable due to a seismic event, the emergency service water supply system would be available to supply water fer plant cooldown of power-accident re-quirements.
The capabilitios of this system were considered in the Atomic Safety and Licensing Board hearings of Decenter 16 and 17, 1980.
The emergency service water supply system design has been reviewed and approved by the Nuclear Regulatory Commission.2 The system's u.ailability and desiga adequacy for seismic events was specifically reviewed in the Safety Evaluation by the Office of Nuclear Reactor Regulation which resulted in the issuance of a license amendment governing availability and surveillance.3 Consideration of transportation accidents and river diversion that have happened in the region historically or may occur during plant lifetime indicate no events which would jeopardize the ultimate heat sink or damage the crib house and the emergency service water supply system.
The plant has been operational 14 years and portions of the site utilized by Dairyland Power Cooperative since 1939.
DPC has also operated 2 other Mississippi River sites ".
periods greater than 20 years.
This represents a good data base fc supporting this conclusion. __
The review of this SEP Topic reaches the conclusion that the ultimate heat sink of the La Crosse Boiling Water Reactor complies with the intent of the Regulatory Position enumerated in Regulatory Guide 1.27, Revision 2, specifically:
Regulatory Position:
"1.
The ultimate heat sink should be capable of providing sufficient cooling for at least 30 days (a ) to permit simultaneous safe shutdoun and cool-doun of all nuclear reactor units that it serves and to maintain them in a safe shutdoun condition, and (b) in the event of an accident in one unit, to limit the effects of that accident safety, to permit simultaneous and safe shutdoun of the remaining units, and to maintain them in a safe shutdoun condition.
Procedures for ensuring a continued capability after 30 days should be available.
Sufficient conservatism should be provided to ensure that a 30-day cooling supply is available and that design basis temperatures of safety-related equipment are not exceeded.
For heat sinks uhere the supply may be limited and/or the temperature of plant intake uater from the sink may eventually become critical (e.g.,
ponds, takes, cooling tovers, or other sink where recirculation be:veen plant cooling vater discharge and intake can occur), transient analyses of supply and/or temperature should be performed.
The meteorological conditions resulting in mamimum evaporation and drift loss should be the vorst 30-day average combination of controlling parameters (e.g.,
deupoint depression, vindepeed, solar radiation).
The meteorological conditions resulting in minimum water cooling should be the vorst combination of controlling parameters, including diurnal variations uhere appro-priate, for the critical time period (s) unique to the specific design of the sink.
The follouing are acceptable methode for selecting these conditions:
Based on regional climatological information, a.
celect the most severe observation for the critical time period (s) for each controlling parameter or parameter combination, oith substantiation of the conservatism of these values for site use.
The individual conditions may be combined uithout regard to histor:' cal occurrence.
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"b.
Select the most severe combination of controtting parameters, including diurnat variations uhere appropriate, for the total of the critical time period (s) based on examination of regionat clima-tologicat* measuremente that are demonstrated to be representative of the site.
If significantly tese than 30 years of representative data are available, other historical regional data should be examined to determine controtting meteorological conditions for the critical time period (s).
If the examin-ation of other historical regional data indicates that the controtting meteorological canditions did not occur within the period of record for the available representative data, then these conditions should be correlated with the available representative data and appropriate adjustments should be made for site con-ditions.
c.
Less severe meteorological conditions nay be assumed when it can be demonstrated that the coneequences of exceeding lesser design basis conditions for short time periods are acceptable.
Information on magnitude, persistence, and frequency of occurrence of controtting meteorological parameters that exceed the design basis conditione, based on acceptable data as discussed above, should be presented.
The above analysis related to the 30-day cooling supply and the excess temperature should include sufficient information to substantiate the assumptione and analytical methods used.
This information should include actual performance data for a similar cooling method operating under load near the j
specified design conditions or justification that conserva-tive evaporation and drift toss and heat transfer values have been used.
A cooling capacity of less than 30 days may be acceptable if it can be demonstrated that rcptenishment or use of an alternate vater supply can be effected to assure the con-tinuous capability of the sink to perform its safety functione, taking into account the availability of replenish-1 ment equipment and limitations that may be imposed on 1
" freedom of movement" fottoving an accident or the occurrence of severe natural phenomena."
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- Climatological in this context pertains to a recent period of record at least 30 years in length. "
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Conclusion:
The ultimate heat sink is the Mississippi River where well documented historical flow records indicate sufficient cooling even during periods of low-flow to exceed the 30-day requirement for both operating and shutdown cases.
No procedures are required for capacity beyond 30 days because the river itself is the ultimate long-term available cooling source.
The highest normal summer water temperatures for the river are in the 800F. to 850F. range.
Because of the relatively low maximum temperature and the high flow rate compared to plant needs (even in the case of historic low flow), no meteorological conditions can occur which will impair the ability of the river to act as the ultimate heat sink.
Regulatory Position:
"2.
The ultimate heat sink complex, whether composed of single or multiple cater sources, should be capable of vithstanding, vithout loss of the sink safety functions specified in regulatory position 1, the following events:
a.
The most severe natural phenomena expected at the site, with appropriate ambient conditions, but uith no tuo or more such phenomena occurring simultaneously, b.
The site-related events (e. g., transportation accident, river diversion) that historically have occurred or that may occur during the plant
- lifetime, c.
Reasonably probable combinations of less severe natural phenomena and/or site-related events, d.
A single failure of manmade structural features.
Ultimate heat sink features, uhich are constructed specifically for the nuclear pouer plant and which are not required to be designed to uithstand the Safe Shutdoun Earthquake or the Probable Ma imum Flood, should at tecst be designed and con-structed to withstand the effects of the Operating Basis Earth-quake (as defined in 10 CFR Part 100, Appendix A) and waterflov based on severe historical events in the region. "
Conclusion:
The ultimate heat sink (Mississippi River) is capable of withstanding the types of severe natural phenomena predicted for the site (e.g., -_,n
the relatively low Safe Shutdown Earthquake).
The intake /outfall manmade structures consisting of a Crib House, a 60" circulating water inlet pipe, a 6" high pressure service water supply pipe, a 16" low pressure service water pipe and a 60" circulating water discharge pipe, were not specifically designed to withstand the proposed.llg site specific criteria which is the basis for the Design Basis Earthquake.5 The Emergency Service Water Supply System was designed to provide the capability for portable pumps to draw directly from the river to provide for shutdown, cooldown or post-accident situations in the case where a seismic event results in loss of any of the man -
made structures.
This redundancy is available for other events including the single failure of a man-made structure, transportation accidents, etc.
It also provides a second system located in a separate building in the event of high winds.
The Crib House has 8
actually been subjected to a greater than 200 year frequency flood and the man-made structure portion of the ultimate heat sink is capable of withstanding waterflow based on historical events in the region.
The ultimate heat sink including man-made structures when redundancy is considered, are capable of withstanding even low probability natural phenomena without total loss of heat sink function.
Regulatory Position:
"3.
The ultimate heat sink should conciet of at least tuo sources of water, including their retaining structures, each with the capability to perform the safety functione specified in regulatory position 1, untees it can be demonstrated that there is extremely Lou probability of losing the capability of a single source.
For close-toop cooiing systeme, there should be at least tuo aqueducts to return the cooling vater to the source, untees it can be demonstrated that there is extremely 100 probability that a single aqueduct can functionalty fait entirely as a reeutt of natural or site-related phenomena.
For once-through cooling systems, there should be at least tuo aqueducts connecting the source (s ) uith the intake structures of the nuclear pouer units and at least tuo aqueducts to discharge the cooling vater vett away from the nuclear pouer plant to ensure that there is no potential for plant flooding by the discharged cooling vater, untees it can be demon-strated that there is extremely Lou probability that a single aqueduct can functioncity fait as a result of natural or site-related phenomena.
Att vater sources and their associated aqueducts should be highty reliable and should be separated and protected such that failure of any one vitt not induce failure of any other." e
Conclusion:
The man-made portions of the ultimate heat sink intake have redundancy for shutdown, cooldown, and post-accident situations by the use of the emergency service water supply system.
Plant cooldown and post-accident conditions which are primarily water makeup situations, are also provided redundancy by the emergency service water supply system.
The river is a single source of water which due to high volume even in recorded historical low flow, demonstrates a low probability of unavail-ability.
The low site specific design criteria (referenced in response to Position 2) make failure of the normal circulating water and discharge piping a low probable event.
Reaulatory Position:
"4.
The technical specifications for the plant should include provisions for actions to be taken in the event that conditions threaten partial loss of the capability of the ultimate heat sink or the plant temporarily does not satisfy regulatory positions 1 and 3 during operation."
Conclusion:
The Technical Specifications for the emergency service water supply system provide provisions to be taken in the event of loss of 3
system capability.
They also provide a requirement for routine surveillance to insure a high probability of system availability.
This concludes the review of this SEP topic.
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REFERENCES (1)
" Geology and Hydrology of a Proposed Reactor Site Near Genoa, Vernon County, Wisconsin", by Alfred Clabsh, Jr.
and Eric L. Meyer.
United States Geological Survey, Water Resources Division, Department of the Interior, August 1962.
(2)
Design Details for Alternate Safe Shutdown System, DPC Letter, Linder to Crutchfield (LAC-7355), February 2, 1981.
(3)
License Amendment #24 to Provisional Operating License DPR-45, NRC Letter, Crutchfield to Linder, February 25, 1981.
(4)
U.
S.
Corp of Engineers, St. Paul, Minnesota (5)
" Site Specific Ground Response Spectra for SEP Plants Located in the Eastern United States"; A Request from Mr. Dennis M. Crutchfield, Chief, Operating Reactors Branch No. 5, USNRC, to All SEP Owners (Except San Onufre),
dated June 17, 1981.
(6)
" Hydrologic Description", A Safety Evaluation Report for SEP Topic II.3.A., June 16, 1981, DPC Letter, Linder to Eisenhut.
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