ML19345D009
| ML19345D009 | |
| Person / Time | |
|---|---|
| Site: | 07000754 |
| Issue date: | 09/29/1980 |
| From: | Hall W, Newmark N NATHAN M. NEWMARK CONSULTING ENGINEERING SERVICES |
| To: | Burkhardt W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML19345D004 | List: |
| References | |
| CON-NRC-03-78-150, CON-NRC-3-78-150 17584, NUDOCS 8012080774 | |
| Download: ML19345D009 (11) | |
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e NATHAN M. NEWMARK CONSULTING m.NGINEERING SERVICES 1114 CIVIL ENGINEERING BUILDING URBANA, ILLINOIS 61801 29 September 1980 Mr. Winston Burkhardt Fuel Reprocessing and Recycle Branch Division of Fuel Cycling and Material Safety US Nuclear Regulatory Commission Washington, DC 20555 Re: Contract NRC-03-78-150 Seismic Evaluation of Building 102 of the General Electric Vallecitos Nuclear Center
Dear Mr. Burkhardt:
This report contains our evaluation of the capability of Building 102 of the General Electric Vallecitos Nuclear Center to withstand seismic shaking and fault motion. Our report is based in part on material contained in Ref.1, as well as on the supporting Engineering Decision Analysis Company reports noted in Ref.1. One of the authors of this report, Dr. W. J. Hall, visited the site and inspected Building 102 in June 1977 and again briefly in April 1979; in the interim both of us 9
have participated in numerous meetings and telephone conversations with personnel from the U.S. Nuclear Regulatory Commission, with EDAC during the early stages, and most recently with LASL concerning evaluation of the noted facility. '
Description of Facility The General Electric Vallecitos f;uclear Center is located 5 miles SSE of Pleasanton, California on th<. north side of the Vallecitos Valley.
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2 Building 102 was constructed in 1956-57 with modifications nade at various times during the period 1969-1974. The building is a one-story structure with a partial basement under the north sector; the Advanced Fuel Laboratory (AFL) is located in the basement in the NE sector of Building 102.
The FML cells are located in the southeast por. tion of the building; working access to the cells is from the ground floor. The elevation of the roof-above the RML cells is significantly higher than the roof over the remainder of the building, and this region over the RML cells is referred to as the "High-Bay Area", whereas the remainder of the structure is referred to as the " Low-Bay Area". The Plutonium ' Analytical Laboratory (PAL) is located i
on the ground floor above the basement in the east portion of the building.
'The aboveground portion of Building 102, of steel frame construction, is P
sheathed with precast concrete panels, metal siding, and glass. The interior walls are constructed of reinforced concrete blocks of two thicknesses, and in some cases wood studs with gypsum board. About half of the 8 in. block walls are in-fills in the structural steel framing. The building was designed generally to comply with provisions of the 1952 Uniform Building Code.
The areas in Building 102 that may contain an inventory of plutonium compcunds from time to time include (a) the Plutonium Analytical Laboratory (PAL), (b) the RML cells, and (c) the Advanced Fuel L 3 oratory (AFL). These areas are designated as the critical building areas in the studies made.
4 The walls of the PAL are constructed 6f precast concrete panels on one side, 8 in. concrete block on two other sides, and 4 in. concrete block on the scuth (an interior wall) side. Thus the weakest structural m--
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3 element, as noted in the referenced report, would be expect 3d to be the south wall of the PAL.
The RML cells are massive reinforced concrete boxes that extend from the basement foundation level to about 17 ft above the ground floor.
The weakest section of the cells is through the ground floor windows and equipcent chases. The cells themselves are extremely massive, and resistant to shaking and faulting.
The basement area, in which the Advanced Fuel Laboratory (AFL) is located, has reinforced concrete exterior walls and concrete block and reinfcrced concrete partition walls. The heavy reinforced concrete basement roof slab is supported by the basement walls, by reinforced concrete columns, The basement floor is not connected structurally and by the interior walls.
to the walls, columns or footings. The glove boxes and exhaust equipment in the basement have recently been reconstructed and connected to the basement structure to provide seismic support in the event of earthquake vibratory motion.
Seismic Evaluation The evaluation of Building 102 was undertaken in a manner consistent with the general natural phenomenon review approach; that is, the analyses employed the most likely values or parameters characterizing the level of resistance of the individual parts of the system or the system as a whole. The approach thereafter involved consideration of an incremental increase in seismic loading effects to identify the load and deformation levels at which the stress or deformation allowables, or some beginning of structural or equipment difficulty, would be expected to occur. The advantage
4 of this approach is that this leads to levels of resistance which can be used in damage scenarios or in incremental evaluation of facility risk assessment.
Seismic Haza"d E
In order to proceed with the EDAC and LASL studies in 1977 and 1978 it was decided to employ a zero period peak horizontal acceleration on the order of 0.8 g for anchoring the free-field response spectra; this motion was considered to be the maximum that might arise from the Calaveras fault.
Similarly, in connection with the postulated Verona fault, it was decided l
to begin studies with a zero period peak horizontal ground acceleration of 0.6 g, a maximum fault displacement of about 2.5 meters, with a dip angle of 15 to 45 degrees, and with concurrent events of shaking and fault motion consistent with about 0.40 g and slip ranging upward to possibly 21/2 meters.
These initial choices were considered to be approximate hazards for which the facilities should be examined and thereafter incremental analyses would indicate the levels at which yielding, distress and damage might occur.
The latest seismic criteria recommended for use in review of the facilities at the Vallecitos site, including Building 102 and GETR, are contained in Attachment 1 to this report; additional backup is provided in It will be noted that the Calaveras related peak acceleration is slightly less acceleration (0.75 g) than noted above, whereas the Verona seismic criteria correspond to 0.6 g peak horizontal acceleration combined with 1 meter (net) slip in any direction.
Evaluation Procedure Details of the structural system: in Building 102 were thoroughly examined and reported in an EDAC report. Upon assuming responsibility for the analysis, LASL also undertook study of the building and its components.
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5 In summary, the analyses centered generally on four different areas of this complex building, namely the low-bay area (particularly as it affects the Plutonium Analytical Laboratory), the high-bay area and the RML cells, and the basement area (containing the Advanced Fuel Laboratory), as well as critical equipment.
The analyses were carried out in both eid: tic and inelastic regimes.
In most cases the response spectrum technique was employed for the dynamic analyses with ductility values employed in the case of irelastic behavior. The damping and ductility values employed were in general agreement throughout with ti.ose normally used for the reevaluation of structures.
In some cases conventional static an& lysis &pproaches were employed. The analysis for faulting included consideration of active and passive earth pressures against floors and walls, and general patterns of possible deformation.
It should be appreciated that the concurrent action of shaking and fault motions is difficult to nandle from a phasing point of view; the calculations were carried out carefully and involved considerable judgment in assessment of. the final results.
4 Summary of Analyses The analyses of the low-bay area indicated that with-a ductility factor of about 1.7 and damping corresponding to about 10 percent of j
critical, the dynamic strength was characterized by resistances associated with accelerations of 0.6 g or greater. Under this level of excitation the shear walls may crack to a degree which could be classed as corresponding
-to moderate to severe damage, even though the frame and the roof probably would still be intact.
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6 In the case of the high-bay area, it was estimated that out-of-plane shaking of the high block walls would lead to severe damage with acceleration of 0.4 g and greater. On the other hand, with in-plane loading, the high-bay system in general was estimated to be good for shaking charac-terized by accelerations of up to 1.0 g or possible greater; the resistance
- obviously depends in part on the support conditions at the bottom, sides and top of the wall.
The P.ML cells are massive reinforced concrete cells with windows at the ground floor and various utility ductways throughout the remainder of the cell. The ant.lvses indicate that cracking in the piers between the observation openings might start with shaking characterized by an acceleration level of about 0.9 g or possibly greater.
It is conceivable that the cells (as rigid units) could be cocked slightly if the floor system in the building were to defonn, but it is unlikely that the cells would overturn, because of the resistance due to the manner in which they are supported (surrounded) by the building structure, including the main floor.
The effect of shaking on the basement is harder to evaluate, but it is estimated that passive earth pressures (equivalent approximately, we estimate, to generated active pressures, i.e., higher than calculater by commonly publicized theories) would be generated with shaking characterized by about 0.6 g acceleration; in turn this general loading would lead to some cracking or yielding in the basement walls with possibly some structural opening to the atmosphere but with no expected loss of confinement in the glove boxes. The resistance of free-standing block walls in the basement was estimated to be about three times that level because of their end fixity and the fact that they are reinforced.
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e In the case of the glove boxes in the basement, with the recent modifications (fasten %g) it is believed that the resistance of these items corresponds generally to excitation on the order of 1 g acceleration or possibly slightly greater.
Surface Faulting The effect of surface faulting upon the low-bay and high-bay areas would be expected to be minimal. The ground faulting may lead to some gross defamation of the base of the structure, but with some lower level of deformation in the high-bay, low-bay or the Plutonium Analytical Lt.boratory within the low bay. A rather detailed analysis was carried out far the 4
RML cells, and it was concluded that the primary effect could be pressures against the lower part of the cells and perhaps deformation of the footings, but this in turn would have little consequence on the cells because the lower parts are nonfunctional; the disturbance could lead to some distortion of the cell and/or tipping (but not overturning) of the cell. Severe distortion may lead to damage of secondary filter ducts and other mechanical components, but one would not expect the primary filters to be damaged.
In the case of the basement, the analysis is more difficult for the task is one of evaluating the effect of the faulting on the basement as a whole and on individual elements such as exterior walls, floor slabs, interior walls, and roof slabs. The interaction of these elements is difficult to evaluate especially when it is not clear how the distortion would occur. The approach taken was one of assessing the gross effect upon the basement if the faults occurred at various locations across the basement region. - As discussed in the LASL report, several modes of distortion are -
j possible; the walls and floor would be expected to experience differential
8 shif ts. Obviously the massive stiff building would serve to resist and "even out" some of the fault defomation.
It is expected that the structure would definitely crack and be deformed grossly, generally commensurate with the deformation pattern of the fault.
In turn such distortion would lead to uneven floors, cracked walls, some cracking in the basement ceiling (a heavy floor), and possibly disruption of the equipment (glove boxes) in the basement area. The distortion would be expected to be less in the upper floors of the building.
Combined Faultino and Shaking On the basis of the LASL and the earlier EDAC studies, our general assessment is that the combined effects would be expected to be about the same as those described previously. The effect of the additional shaking with the faultit g would be one of leading to additional disruption of the critical equipment in the basement area and perhaps some additional damage in the upper structural levels although the level of shaking is currently estimated to be less than that which would lead to quite severe damage.
Damaae Scenarios We have examined the damage scenarios with care in the light of the remaincer of the report, and they appear reasonable.
For shaking characterized by peak accelerations up to about 1.10 g, which would seem reasonable, it is unlikely that even minor damage would be evident in any of the critical facilities or equipment.
For accelerations in the range of 0.10 g to 0.4 9 it is reasonable to expect that some of the walls would exhibit cracking; such distress could lead to a need for remedial repair to make the basement ( AFL), for example, and the plutonium Analytical
9 Laboratory cell areas leaktight.
In the range of 0.4 g to 0.8 g one would expect distorted frames'and cracked or damaged walls in the low and high bays, and possibly severe cracking in the basement walls. Ecof and floor slabs also would be expected to experience cracking. Damage scenarios above 0.8 g would be progressively worse although as indicated in the analyses, many parts of the structure should be able to withstand shaking characterized by 1 g or greater; hence the damage may be heavy in some portions and light in others.
The damage scenarios for faulting appear reasonable and progress from light to moderate degrees of distortion in the walls and floors, especially in the basement areas as one would expect.
Under the combined shaking and faulting, one would expect to see distortion in walls, floors, and ceiling in the basement and some distortion in equipment. The relative displacements could be significant but even so,
.i for the hazards employed in the analyses, a good portion of the structure could be expected to remain intact.
Equipment which had been shaken loose could slide or shift, or if still attached to the floor or wall it could be distorted. Possibly some pieces of masonry could fall and strike the glove boxes, but in view of the reinforced walls such failures would be limited.
It should be appreciated that the hazards employed in the LASL study, and reported in the LASL scenarios, go far beyond the generally cceepted seismic review criteria (Attachments 1 and 2).
Concludino Statement On the basis of our review of the physical facility and our evaluation of the studies carried out, we believe the camage scenarios to be generally realistic of the actual effects that might be observed
10 for the seismic hazards postulated.
In some cases, especially for the acceleration range of 0.4 to 0.8 g, based on judgment, we believe the damage could be slightly less than that described in the scenarios.
Respectfully submitted,
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32 N. M. Newmark
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W. J. Hall i
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Reference:
1.
" Seismic Evaluation of Building 102 of the General Electric V Ilacitor.
Nuclear Center",' by G. E. Endebrock, LASL Report Submitted to 1.
Burkhardt, USNhC, Los Alamos Scientific Laboratory, Los Alamos, New Mexico, 1979.
t Attachments:
1.
" Seismic Evaluation of Vallecitos Site", by N. M. Newmark and W. J.
Hall, N. M. Newmark Consulting Engineering Services,' Urbana, Ill.,
under Contract NRC-03-78-150, 14 April 1980.
2.-
" Seismic Evaluation of Vallecitos Site -- Basis of Earthquake Ground Motion Design Criteria", by W. J. Hall and N. M. Newmark, N. M. Newmark Consulting Engineering Services, Urbana, Ill., under Contract NRC 78-150, 29 September 1980.
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