ML20205B770
| ML20205B770 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 09/06/1985 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20205B762 | List: |
| References | |
| NUDOCS 8509120234 | |
| Download: ML20205B770 (6) | |
Text
.
ENCLOSURE LA CROSSE BOILING WATER REACTOR SAFETY EVALUATION REPORT DOCKET NO.:
50-409 IPSAR SECTION 4.7.1 CONTAINMENT STABILITY IPSAR SECTION 4.7.2 STACK STABILITY 1.
INTRODUCTION SEP Topic II-3.B " Flooding Potential and Protection Requirements" and Topic 2
11-3.8.1 " Capability of Operating Plants to Cope with Design Basis Flooding Conditions" indicate that:
(1) the original design basis
~
flood for the LACBWR site corresponds to the flood which produces a surface water elevation at nominal station grade, elevation 639 feet mean sea level (MSL); (2) safety related structures have their grade level access and floors above the predicted water elevations for floods up to a 500-year occurrence interval; and (3) the site can be shut down and maintained in a safe shut down condition for floods significantly l
greaterthanthestandardprojectflood(Ref.1). The design basis flood level (DBFL) as developed by the staff consists of a probable maximum flood of 658 ft (MSL) with an associated 3-foot wave height end a corresponding flow of 1,000,000 cfs(Ref.2&4). Since this DBFL is substantially higher than the original design basis flood, the staff o
i requestedDairylandPowerCooperative(DPC)toevaluatetheeffectsof the DBFL on the LACBWR structures.
l l
This report sumarizes the staff's evaluation of the licensee's analyses of the stability of the containment and stacks under flood conditions. The staff's review was conducted in accordance with the procedures described intheStandardReviewPlan(NUREG-0800)Section2.5.4andcurrent
~
engineering practice.
0509120234 850906 PDR ADOCK 05000409 P
2.
EVALUATION 2.1 Containment The evaluation of the Reactor Containment was performed by a DPC consultant using the Black & Veatch computer program described in reference 2.
Sliding and overturning of the containment are resisted by the 30 feet of embedment of the containment vessel.
The soil properties used in the analyses for the reactor containment structure are based on the subsurface investigation performed by Raymond, Inc., during 1962 at the LACBWR site. These borings were performed prior to the foundation pile installation and do not reflect the compaction effects due to pile driving. Hence, the subsurface parameters used to determine foundation resistance are conservative.
The parameters used for calculating soil sliding resistance and the lateral. resistance of the piles are: (a)loosesand,UnifiedSoil Classification SP, and (b) angle of internal friction Jf= 30'.
The resistance against overturning was determined by calculating the maximum individual pile loads due to the overturning loads on the structure from the wind and wave forces as described in reference 5.
The factors of safety calculated by Black & Veatch are 2.1 for sliding and 2.2 for overturning (Ref. 3).
,.. Since the soil properties used in the analyses are reasonable and the factors of safety are above the minimum value specified in the Standard Review Plan (SRP), the staff considers these analyses are acceptable and concurs with the licensee's conclusion that the containment is stable under flood conditions.
2.2 STACKS The stability analyses of the stacks G2 and G3 were conducted by Black &
Veatch as described in reference 4. Stack G3 consists of a 500-foot tall reinforced concrete shell with a self supporting steel liner. The l.
stack is supported on a 75-foot diameter, octagonal-shaped, soil supported, reinforced concrete mat foundation. Stack G2 is a 350-foot tall reinforced concrete structure which is supported on a pile supported reinforced concrete mat. Flood and wave loads similar to those used for the containment stability analyses were used to analyze the stability of the stacks.
1
The subsurface soil parameters used in the stability' analyses for Stack G3 are based on the results of the liquefaction investigation conducted in December 1980. The results of the standard penetration tests were used in accordance with NAVFAC DM 7.1 & 7.2 to determine the soil parameters for the stability analyses. The soil parameters are as follows: (a) medium dense sand, Unified Soil Classification SP (b) angle of internal friction ff = 32.2' and (c) coefficient of friction between foundation and soil, 0.4.
The subsurface parameters used in the analyses for Stack G2 were obtained from the investigation conducted in July 1980. Borings were drilled through the stack foundation mat to determine precisely the subsurface conditions below the stack. The soil parameters are: (a) medium dense to d
dense sand, Unified Soil Classification SP, SP-SM, (b) angle of internal friction f = 33', (c) saturated unit weight 122.4 and (d) coefficient of friction between foundation and soil, 0.4 The analyses showed that the factors of safety are (Ref. 4):
Stack No.
Sliding Overturning G2 3.6 1.7 G3 5.8 5.2 i
l
- ,i l
Since the soil parameters used in the analyses are reasonable and the i
factors of safety are above the SRP specified minimum value, the staff considers these analyses are acceptable and concurs with the licensee's conclusions that the stacks are stable under flood conditions.
3.
CONCLUSIONS Based on the review of the information (Ref. I thru 5) provided by the licensee, the staff concludes that the reactor containment and the stacks have capabilities against sliding and overturning under DBFL flood conditions.
i L
i l
i
}
,* 4.
REFERENCES:
(1) Letter from F. Linder of DPC to D. Crutchfield of NRC, dated May 12, 1982, "DPC LACBWR Provisional Operating License No.
DPR-45" (2) Letter from Linder (DPC) to Crutchfield (NRC), dated October 22, 1982, "SEP Topic III-3.A - Effect of High Water Level on Structures (REY. 1)."
(3) Letter from Linder (DPC) to Eisenhut (NRC), dated February 14, 1983, "DPC LACBWR SEP Topic III-3.A Safety Evaluation Report - Effect of High Water Level on Structures."
(4) LetterfromLinder(DPC)toCrutchfield(NRC),datedSeptember 29, 1983, "DPC LACBWR Provisional Operating License No. DPR-45, Integrated Plant Safety Assessment - SEP, NUREG-0827 - Full Tenn License Comitments "
(5) Letter from Linder (DPC) to Crutchfield (NRC), dated July 3,1984, "DPC LACBWR Integrated Plant Safety Assessment - SEP"
>