ML18051A283
| ML18051A283 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/31/1982 |
| From: | JOHN A. BLUME & ASSOCIATES, ENGINEERS |
| To: | |
| Shared Package | |
| ML18051A282 | List: |
| References | |
| TASK-03-06, TASK-3-6, TASK-RR URS-JAB-8249, URS-JAB-8249-R01, URS-JAB-8249-R1, NUDOCS 8301240077 | |
| Download: ML18051A283 (23) | |
Text
Consumers Power Company Docket 50-255 SEISMIC STRUCTURAL - INTEGRITY EVALUATION OF SELECTED ELECTRICAL EQUIPMENT AT PALISADES NUCLEAR POWER PLANT DECEMBER 1982 15 Pages
,-- a3012400ii "83oiiel" _________.
PDR ADOCK 05000255 P
PD~_
OC0183-0005B-NL02 1/ 18 /83
SEISMIC STRUCTURAL-INTEGRITY EVALUATION OF SELECTED ELECTRICAL EQUIPMENT AT PALISADES NUCLEAR POWER PLANT Revision 1 This report shall be considered to be preliminary pending completion of URS/Blume quality assurance reviews.
Prepared for Consumers Power Company Jackson, Michigan December 1982 Prepared by URS/John A. Blume & Associates, Engineers 130 Sylvan Street Danvers, Massachusetts 01923 URS/JAB 8249
FORM 4.1-1 URS/BLUME DOCUMENT APPROVAL SHEET DOCUMENT T 1 TLE : __
s_e __ i_s_m_i _c_S_t_r_u_c_t_u_ra_l.;...* _l_n_t_eg_r *_, t_y_E_v_a_l u_a_t_i_o_n_o_f _S_e_l_e_c_t_e_d_E_l_e_c_t_r_i _ca_l _
Equipment at Palisades Nuclear Power Plant DOCUMENT TYPE:
CriteriaO lnterfaceO ReportKJ SpecificationO OtherO PROJECT NAME:
Palisades Electrical Equipment JOB NO.:
~
CLIENT:
Consumers Power Company This document has been prepared in accordance with the URS/Blume Quality Assurance Manual and Project requirements.
Initial issue REVISION RECORD:
Revision No.
Rev. 9 5/14/82 Reviewed By/Date Description of Revision Editorial corrections
- 1.
- 2.
- 3.
- 4.
1 2
CONTENTS INTRODUCTION....................................................
1 Background ***************************************************
1 Further Evaluation *******************************************
1 Report Organization ******************************************
2 ANCHORAGE OF ELECTRICAL DEVICES.................................
3 Methods and Criteria *****************************************
3 Results of the Evaluation ************************************
4 MOTOR CONTROL CENTERS AND 2...................................
Description of the MCC Assembly..............................
Methods and Criteria *****************************************
Results of the Evaluation ************************************
SUMMARY
REFERENCES......................................................
FIGURES Motor Control Centers 1 and 2 and Details........................
Details of Removable Shelf and Vertical Bus Support, Motor Control Centers 1 and 2..........................................
5 5
8 9
11 12 6
7 i i i
~lRi~/Blume
1
- INTRODUCTION At the request of Consumers Power Company, URS/John A. Blume & Associates, Engineers (URS/Blume), performed an evaluation of selected electrical equipment at the Palisades Nuclear Power Plant near South Haven, Michigan, for structural integrity under seismic loads.
The evaluation was conducted as part of the Systematic Evaluation Program of the U.S. Nuclear Regulatory Commission (NRC).
Background
In an earlier study,l URS/Blume investigated the seismic anchorage of safety-related electrical-equipment cabinets at the Palisades plant.
Items that were found to require additional seismic restraints were modified in the latter part of 1981 during a refueling outage.
A complete structural-integrity evaluation requires that the adequacy of the load path extending from electrical devices within equipment cabinets to the anchorage of the unit also be assessed.
In such an evaluation, three segments of the load path are of particular concerns the anchorage of electrical devices, the walls and panels of the cabinet, and the region in which support for the cabinet is provided.
The weakest segment of the load path is generally the cabinet-support region.
Therefore, as part of the anchorage study, two-point supports were designed for electrical equip-ment cabinets wherever possible.
The two-point method of support supplies lateral bracing from the top of the unit to adjacent concrete walls, in addition to anchorage at the base of the unit by means of anchor bolts.
In comparison with base-only support, this method results in higher natural frequencies, lower seismic accelerations and structural stresses, and a reduction in anchorage requirements for the electrical devices within the cabinets.
Further Evaluation During the phase of work recently completed, a generic review of the cab-inet anchorage of safety-related motor control centers (MCC), switchgears, 1 -
QJJ~~/Blume
and control panels was conducted.
Low-voltage and medium-voltage switch-gears and all MCCs except for MCC 1 and MCC 2 were provided with two-point support, which would result in low seismic forces on the cabinet supports.
MCC 1 and MCC 2 are located in the auxiliary building at elevation 610 ft, where seismic motion is expected to be stronger than at most other loca-tions of safety-related electrical equipment at the Palisades plant. *The control room is an exception.
MCC 1 and MCC 2 were therefore evaluated for seismic structural integrity on the basis of worst-case sampling.
Evalua-tion of control panels was not a part of the work reported here; it will be carried out in a separate study.
Evaluation of electrical-device anchorages was performed on a generic basis and is applicable to all safety-related equipment cabinets at the Palisades plant.
Report Organization Section 2 of this report describes the methods and criteria used to eval-uate the anchorage of electrical devices at the Palisades plant and pre-sents the results of the evaluation.
In Section 3, a detailed description of MCC 1 and MCC 2 is given.
Evaluation of these MCCs was the primary focus of effort i~ this structural-integrity assessment.
A description of the methods and criteria that were used and the results of the investiga-tion are also presented in Section 3.
Section 4 summarizes the work done in this phase of the study and is followed by a list of the references cited in the report.
2 -
lLllRi~/Blume
- 2.
ANCHORAGE OF ELECTRICAL DEVICES Methods and Criteria At the outset of the investigation, a generic study of the types of anchor-age used for electrical devices within the equipment cabinets at the Pali-sades plant was performed.
To assess the adequacy of the anchorage, the design-basis earthquake (DBE) loadings, as defined by the floor-response spectra for the containment building2 and for the auxiliary building,3 were used.
The curves for 5% damping presented in those analyses were chosen for this study.
For analysis of electrical-device anchorage, the equivalent-static-load method was selected.
For analysis of horizontal loading, the highest horizontal-response spectrum peak encountered at locations of safety-related electrical equipment in the plant was used.
That value was in-creased to provide a conservative estimate of the worst response to be expected at the midpoint of a simply supported rectangular plate in the vertical plane, located at the top of an unbraced electrical equipment cabinet.
Because electrical equipment cabinets are generally rigid (i.e.,
have a fundamental frequency higher than 33 Hz) in the vertical direction, the zero-period acceleration (ZPA) value of the DBE spectrum was used for analysis of vertical loading.
The computed horizontal-acceleration value used for evaluation of device anchorage was Sh= 21.Bg.
The vertical-acceleration value was Sv = 0.20g; this value was added to the dead load of the electrical device.
A list of electrical devices, with the manufacturer's name and model number and details of anchorage, had been compiled during a URS/Blume field sur-vey.
The actual weights of the devices had been determined from manufac-turers' catalogues or had been conservatively estimated.
The weights for the MCC 1 and MCC 2 devices ranged from 1-1/2 lb for an overload heater coil to 24 lb for a starter.
The anchorage patterns varied from two-bolt to four-bolt configurations using bolts of 1/8-in. to 1/4-in. diameter. ~~~/Blume
A static analysis of six conman anchorage configurations for electrical devices was performed for bolts of 1/8-in ** 3/16-in ** and 1./4-in. diameter.
The stresses from dead load and the vertical seismic load were combined by the absolute-sLm method with those from the more critical of the two hori-zontal directions in each case.
This method is in agreement with the method described in the final safety analysis report for the Palisades plant.~ Maximum allowable weights were then calculated for various aspect ratios of the electrical devices. with static loads being applied at the geometric center of the device.
The structural acceptance criteria for the bolts were those defined in the NRC 1s standard review plan. 5 Section 3.8.4.
for the safe-shutdown earthquake (SSE) load combination.
Thus. the allow-able stress limits used for the bolts were 1.6 times the allowable values for elastic design defined in the American Institute of Steel Construction (AISC) manual.6 Results of the Evaluation The methods and criteria described above were applied to the electrical devices in MCC 1 and MCC 2.
All electrical device anchorages for these two MCCs were found to be acceptable.
Consumers Power Company will evaluate devices located in other electrical equipment cabinets by using the methods and criteria applied to MCC 1 and MCC 2. (UJ~~/Blume
- 3.
MOTOR CONTROL CENTERS 1 AND 2 Description of the MCC The evaluation of MCC 1 and MCC 2 was based on dimensional information ob-tained from the manufacturer and on data gathered during a field visit by URS/Blume_personnel.
These MCCs are Cutler-Hammer products.
They comprise 19 units of essentially identical basic construction.
(See Figure 1.)
The only significant difference among units is in the size of the shelves to which electrical devices are anchored.
The entire MCC assembly is attached to two C4 X 5.4 channels, which are themselves anchored to a concrete ped-estal.
Each unit is approximately 7 ft 4 in. high, 1 ft 8 in. wide, and 1 ft 8 in. deep and is constructed of 12-gauge bent-steel plates.
Z-shaped vertical stiffeners and channels running the height of the side plates of the MCC units are used for the attachment of doors, device shelves, and electrical bus bars.
These are shown in the details of Fig-ures 1 and 2.
The two side plates are connected structurally through the door sills, the insulated vertical bus supports, and the device shelves, as shown in Figure 2.
All electrical devices within MCC units are anchored to the backboard of a U-shaped removable shelf consisting of a top plate, a bottom plate, and a back plate.
The shelf is anchored to the vertical channel of the MCC through a latch-and-bracket arrangement (see Figure 2).
Each MCC unit is supported by four legs, which are part of the 12-gauge bent-steel plate.
Each leg is bolted to the supporting C4 X 5.4 channel by a 3/8-in.-diameter bolt.
Three pairs of 1/4-in.-diameter bolts connect the units to each other.
The bottom pair is approximately 1-7/8 in. above the legs, ensuring composite behavior of the two side-by-side legs of adjoining units.
The mass of each of the 19 units of the MCCs was estimated on the basis of drawings an~ from information obtained from the manufacturer.
An average value for the 19 units was calculated, and that value was increased by 20%
to account for miscellaneous bolts and nuts, to allow for the estimated weight of devices, and for conservatism.
The resultant value, which was used in the evaluation, was 630 lb per unit. (Lll[Ri~/Blume
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- DESCRIPTION Item ND Location Elevation ITEM DESCRIPTION Consumers Power Company URS/Blume 8249 Pa I i~drs Nuclear Geooraling Plant Job NO t-tCG-1~ t-1CC-'2 8249-0-001 Drawi NO REV 0
Sheet '2 of '2 FIGURE 2 DETAIL OF REMOVABLE SHELF AND VERTICAL BUS SUPPORT, MOTOR CONTROL CENTERS 1 AND 2
Methods and Criteria The dynamic characteristics of the MCCs were estimated by using simple analytical models.
The lowest frequency calculated was 21.6 Hz for the rocking mode in the lateral (front-to-back) direction.
That value is sig-nificantly beyond the peak frequency of the floor-response spectra at ele-vation 610 ft of the auxiliary building. 3 However, since the dynamic properties were determined on the basis of a simple analytical evaluation, without substantiation by testing, the equivalent-static-load method was used for the structural-integrity evaluation.
The peak frequency of the 5%-damped DBE floor-response spectrum was increased by 50% for the horizon-tal direction, in accordance with the requirements of*Section 3.7.2 of the NRC's standard review plan.s The vertical-acceleration level was based on the ZPA of the vertical spectnun because of the rigidity of the MCCs in that direction.
The horizontal-acceleration value used was Sh= 2.5g.
A vertical-acceleration value of S = 0.21g was added to the dead-load com-v ponent.
The general approach that was used was to calculate the maximum horizontal capacity of each of the critical segments of the load path of the MCC.
Those segments ares The mechanism connecting the supporting plate for the electrical devices to the structural framing of the MCC cabinet The structural framing and side plate panel of the MCC cabinet The supporting legs of the MCC cabinet and their anchor bolts The channel, bolted to the concrete floor, that supports the entire MCC The structural calculations were performed for the lateral and longitudinal directions of the MCC by combining stresses due to the vertical loads (the DBE and dead loads) with those due to a 1g horizontal-acceleration compo-nent of seismic motion in each direction on an absolute-sum basis.
The structural acceptance criteria for the evaluation were those defined in Section 3.8.4 of the NRC's standard review plan5 for the SSE load combina-8 UJJ~~/Blume
tion.
All allowable stress limits used were 1.6 times the allowable I
stresses for elastic design defined in the AISC manua1 6 and in the American Iron and Steel lnstitute 1s (AISI) specifications for cold-formed steel mem-bers.7 However, no values greater than the material yield stress were used.
Because of a lack of information on the type of material used for the construction of the MCCs, a yield-stress value of 36 ksi was assumed.
Various ASTM grades of structural steel range in yield stress from 25 to 50 ksi and others could reach 65 ksi; however, as stated in Section B.1 of the AISI specification, "sheet ~nd strip steel with yield points lower than 33 ksi and plate steels lower than 36 ksi are rarely used for structural pur-poses.117 Results of the Evaluation Conservative assumptions were made throughout the evaluation, and judgment was used to decide which of the segments of the load path were critical.
All critical elements were found to have sufficient seismic capacity to meet the requirements of acceptance criteria for postulated DBE motion at elevation 610 ft of the auxiliary building.3 The leg of the HCC was found to have the lowest capacity for combined axial and bending stresses due to dead load and to vertical and longitudinal earthquake loads.
This struc-tural element was found to possess a conservatively calculated horizontal-seismic-load capacity of 2.5g.
The horizontal-seismic-load capacity of the support for the shelf to which the electrical devices are anchored was calculated to be about 25g.
This high capacity is due primarily to the light weight of the shelf and the devices.
The maximum weight of small shelves is approximately 45 lb; that of large shelves is approximately 62 lb.
The horizontal capacity of the unit's structural framing and side panels was calculated to be about 9g, the controlling stress being the allowable elastic buckling stress due to dead load and vertical and lateral earthquake loads.
This directional com-bination was also the controlling combination for the stress in the C4 X 5.4 channel that supports the entire MCC assembly, resulting in a horizontal-load capacity of 2.6g. UJJ~~/Blume
Because the capacities of all critical elements of the MCC cabinet were conservatively estimated to be at the required 2.59 horizontal level or abov~, it is concluded that MCC 1 and MCC 2 can be expected to survive the postulated DBE event without significant structural failure.
10 -
llJJlRi~/Blume
- 4.
SUMMARY
This report presents the methodology and criteria for a structural-integrity evaluation of MCC 1 and MCC 2 of the Palisades Nuclear Power Plant, concentrating on the critical segments of the load path.
Because the evaluation resulted in a judgment that all of the verified elements of the cabinets are structurally acceptable, the MCCs are expected to survive the postulated DBE for the site without significant structural failure.
Furthermore, because all of the switchgears have been provided with two-point support, the same statement can be made of those items.
In addition, an evaluation of the anchorage of electrical devices within the MCC cabinets was performed.
All items were found to be acceptable.
Maximum allowable weights for electrical devices were developed for six co1T1T10nly found anchorage patterns and for three bolt diameters, on the basis of very conservative assumptions.
Because of these conservative as-sumptions and because the evaluation was based on a generic review, the maximum allowable weights obtained for the electrical-device anchorages are applicable to all items of safety-related electrical equipment cabinets at the Palisades plant.
lUJ~~/Blume 11 -
REFERENCES
- 1.
u*RS/John A. Blume & Associates, Engineers, Consulta.tion fol' Safety-Rela.ted Electl'ioo.l Equipment at Fl:llisades NucleaP POIVeP Plant, Revi-s ion 1, URS/JAB 8013, Danvers, Massachusetts, January 1982.
- 2.
Bechtel Engineering Corporation, ReactoP Building Seismic Aralysis, ConsumePs POIVel' Comp:J..ny, Palisades Plant, CPCO-GW0-8428, Bechtel Job 10512-031, San Francisco, California, 1969.
- 3.
Bechtel Engineering Corporation, Seismic Design RequiPements fol' Equip-ment Looo.ted in the AuxiliaPy Building, Consumeps POIVeP Comp:lny, Palisades Plant, Specification 10512-034-c-17507, Attachment 2, Revi-sion 0, San Francisco, California.
- 4.
Consumers Power Company, Firal Safety Aralysis Repol't fol' Palisades Plant, Appendix A, Design Basis for Structures, Systems, and Equipment (Except Containment Structure) for Palisades Plant, Jackson, Michigan, Revised October 24, 1980.
- 5.
U.S. Nuclear Regulatory Commission, Sta.ndal'd Revieru Plan fol' the Review of Safety Aralysis RepoPts fop NucleaP POIVeP Plants, LWR Edition, NUREG-0800, Office of Nuclear Reactor Regulation, July 1981.
- 6.
American Institute of Steel Construction, Inc., Manual of Steel Con-stPUction: Specifioo.tion fop Design, Fabl'ioo.tion, and EPection of StPUctunil Steel fop Buildings, 8th Edition, New York, New York, 1980.
- 7.
American Iron and Steel Institute, Specifioo.tion fol' the Design of Cold-FoFmed Steel StPU<:tunil MembeFs and Commenta.zry, Washington, D.C.,
1968.
12 -
[1JJU?a~/Blume
General Offices: 212 West Michigan Avenue, Jackson, Ml 49201 * (517) 788-0550 ffl January~ 1983 Dennis M Crutchfield, Chief Operating Reactor Branch N~5 Nuclear Reactor Regulation US Nuclear Regulatory Comm ss on Washington, DC 20555 DOCKET 50-255 -
LICENSE DPR PALISADES PLANT -
SEP TOPIC III-6, "SEISMIC DESIGN CONSIDERATIONS", RESPONSE TO COMMITMENT CONCERNING ELECTRICAL COMPONENTS EVALUATIONS By letter dated August 17, 1982, Consumers Power Company provided the NRC with a status update and schedule for addressing one outstanding safeti issue related to SEP Topic III-6, "Seismic Design Considerations", for the Palisades Plant.
In that letter we indicated that evaluations of electrical cabinet integrity and mounting adequacy of internal components were being conducted and it was expected that this work would be completed by 12/20/82.
This letter submits our response to this commitment.
~The attached preliminary report by URS/John A Blume & Associates, Engineers,
..fJ-k;;J-
~ \\mtitled "Seismic Structural - Integrity Evaluation of Selected Electrical
~
- 1(~~.Y.iquipment at Palisades Nuclear Power Plant", provides Consumers Power Company
~
~.A"',,V-seismic analysis of Motor Control Centers (MCC) 1 & 2.
In addition to the MCC
> i,.&'J"Ttrb. 1 & 2 analysis, comp~t anchorage of devices (ie, transformers, circuit
.f!-~ #'V breakers, C§i"~:ormelr~)etc) in switchgear rn, BQnsidered to be Fepresentative
~"'{i Qf medium vglta~itchgear at Palisadest was analyzed using the methodology
~~~-~ developed in the attached report for evaluating anchorage of subcomponents at
~~-~~* the Palisades Plant.V The methodology developed in the attached report was
- ~ f~_:_ extended as required for additional anchorage configurations and for
~
bolt diameters.
In all cases, the anchorage of devices in switch-
~
found to be acceptable.
An investigation of the control room resulted in the identification of Control Room Panels C-11, C-llA, C-
. _c /13, C-04, C-06 and C-126 as safety-related control pane In addition 1
safety-related control panels in the control room, t~e
- tt.:t5 *\\
located at elevation 590'-0 of the auxiliary buildin
~-
a ently added in the control room and has been quali ied separate~:~\\~
ults of the qualificati
~ 1 a~e not ~ncorporated in the attached e~
n report.
L_
J In addition to evaluating anchorage of devic~e components in safety-related cabinets outsid~ontrol ~~-nt 1
ontainment were checked OC0183-0005A-NL02
~I
-fl.>-
DMCrutchfield, Chief Palisades Plant SEP Tomi II-6 January,)4, 1983 11 to ensure that anchor devices (ie, bolts and screws) were in place as required by the original construction specifications.
The component check revealed all anchor d~vices o be in place.
~oll-The(;~isifig~ on~l room panels (such as safety-related Panels C-11, C-12,
,C-1~
C-06) were part of an earlier study by URS/John A Blume to ure stability of safety-related electrical equipment at Palisades.
These~
els were provided with additional base support plus bracing from the top ~
ntrol panels.
Such support arr~ent results in higher natural frequencies, lower response acce~ons and therefore, lower stresses in the control panel structures.
Although Consumers Power Company has not performed a rigorous stress analysis for structural integrity of control room panels for the Palisades Safe Shutdown Earthquake (SSE), structural integrity of the control room panels is adequate due to their two-point support.
This conclusion is also substantiated by the results of an evaluation conducted by EQE, Inc entitled "Program For The Development Of An Alternativeeach To Seismic Equipment Qualification", which indicated that adequate!
pported electrical equipment has proven not to be a problem during an ear hquake event.
Control Panel C-33, located at elevation 590'-0 of the Auxiliary Building is P~.Q.l:'-te-a-,.only at its base. Since MCC 1 & 2 are supported only at the base and they are located at a higher elevation which exposes them to r accelerations, it was determined that MCC 1 & 2 represent the worst
/"'case for the structural integrity issue. It was, therefore, concluded that Of--/ Since the results of the enclosed report show MCC 1 & 2 to be structurally 1/ adequate, Control Panel C-33 is also expected to be capable of withstanding the Palisades SSE.
The issue of anchorage of subcomponents in the control panels and structural t::i..
integrity of Control Panel C-126 remains to be addressed.
Control Panel C-126_,t.u J-~(J.
contains safety-related temperature and pressure indica;prs and control
~
£1 1t switches for hydrazi~e~ddition ** 8'ft'tl ;it; s~p,~ed ~V'~:itb@ ~
Consumers
~
Power Compan~~-MITuations of these remaining items will show adequate seismic resi '{Il, e ased on our experience to date.
It is expected that these evaluations w1 be completed by July 1, 1983.
Kerry A Toner (Signed)
Kerry A Toner Senior Licensing Engineer CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades OC0183-0005A-NL02
Consumers Power Company Docket 50-255 SEISMIC STRUCTURAL - INTEGRITY EVALUATION OF SELECTED ELECTRICAL EQUIPMENT AT PALISADES NUCLEAR POWER PLANT
- DECEMBER 1982 OC0183-0005B-NL02 r
1/17/83
I I
LICENSING CORRESPONDENCE - RECORD
SUMMARY
DATE:
January 17, 1983 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
SEP TOPIC III-6, "SEISMIC DESIGN CONSIDERATIONS", RESPONSE TO COMMITMENT CONCERNING ELECTRICAL COMPONENTS EVALUATIONS
SUMMARY
This letter provides CPCO response regarding the electrical cabinet integrity and mounting adequacy evaluations.
The evaluations, conducted by URS/John A Blume & Associates and documented in a report entitled "Seismic Structural - Integrity Evaluation of Selected Electrical Equipment at Palisades Nuclear Power Plant", demonstrated that all the cabinets investigated are structurally acceptable.
One final commitment remains to be completed (see below).
COMMITMENTS MADE:
Perform evaluations of anchorage of subcomponents in the control panels and structural integrity of Control Panel C-126 by July 1, 1983.
PREVIOUS NRC/CP CO CORRESPONDENCE CPCo 8/17/82 AIR NO UFI NO 950-02000/13100 99*12 INDIVIDUALS PROVIDING INFORMATION PJKlein URS/John A Blume & Associates CONCURRENCES PJKlein JLKuemin KAT oner ORIGINATOR JDaiza MI0183-0009A-NL02 SPECIAL DISTRIBUTION JLKuemin KWBerry INDIVIDUALS ASSIGNED RESPON-SIBILITY FOR IMPLEMENTING COMMITMENTS:
AIR A-NL-83-003 prepared and forwarded to DRHughes (NPS)
COST/BUDGET IMPACT Actual/Potential Year (s) 1983 Materials/Parts NO Labor 4 Man-Months Capital NO Contractors NO
It LICENSING CORRESPONDENCE -
RECORD
SUMMARY
~---*~r DATE:~
V DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
SEP TOPIC III-6, TO COMMITMENT CONCERNING ELECTRICAL
~~'d "SEISMIC DESIGN CONSIDERATIONS", RESPONSE COMPONENkS VALUATIONS
SUMMARY
This letter provides CPCO response 09l the electrical cabinet integrity and mounting adequacy evaluations.
The evaluations, conducted by URS/John A Blume & Associates and documented in a report entitled "Seismic Structural - Integrity Evaluation of Selected Electrical Equipment at Palisades Nuclear Power Plant", demonstrated that all the cabinets investigated are structurally acceptable.
One final commitment remains to be completed (see below).
COMMITMENTS MADE:
Perform evaluations of anchorage of subcomponents in the control panels and structural integrity of Control Panel C-126 by July 1, 1983.
PREVIOUS NRC/CP CO CORRESPONDENCE CPCo 8/17/82 AIR NO UFI NO 950-02000/13100 99*12 INDIVIDUALS PROVIDING INFORMATION PJKlein URS/John A Blume & Associates SPECIAL DISTRIBUTION JLKuemin KWBerry fl:r/'.-l/-,JL-'i';3-M3 P"t°J I.,
\\
~
~
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..J /..:t't,
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~* JI.
INDIVIDUALS ASSIGNED RESPON-ffo.,..-
- ..- 1:
SIBILITY FOR IMPLEMENTING
/
/
~
COMMITMENTS:
ft 1/21/83
?
PJKleiR (NP~ tg perfg
~Dei:iia (NLD) to write~AIR ey v evaluations b':y 6/15/8*3/~---------------~
CONCURRENCES PJKlein JLKuemin KAT oner ORIGINATOR JDaiza MI0183-0009A-NL02 COST/BUDGET IMPACT Actual/Potential Year(s) 1983 Materials/Parts Labor Capital NO Contractors NO
consumers POYJer company General Offices: 212 West Michigan Avenue, Jackson, Ml 49201 * (617) 788-0560 January 18, 1983 Dennis M Crutchfield, Chief Operating Reactor Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR
- PALISADES PLANT -
SEP TOPIC III-6, "SEISMIC DESIGN CONSIDERATIONS", RESPONSE TO COMMITMENT CONCERNING ELECTRICAL COMPONENTS EVALUATIONS By letter dated August 17, 1982, Consumers Power Company provided the NRC with a status update and schedule for addressing one outstanding safety issue related to SEP Topic III-6, "Seismic Design Considerations", for the Palisades Plant.
In that letter we indicated that evaluations of electrical cabinet integrity and mounting ade.quacy of internal components were being conducted and it was expected that this work would be completed by 12/20/82.
This letter submits our response to this commitment.
The attached preliminary report by URS/John A Blume & Associates, Engineers, entitled "Seismic Structural - Integrity Evaluation of Selected Electrical Equipment at Palisades Nuclear Power Plant", provides Consumers Power Company seismic analysis of Motor Control Centers (MCC) 1 & 2.
In addition to the MCC 1 & 2 analysis, component anchorage of devices (ie, transformers, circuit breakers, etc) in switchgear lD was analyzed using the methodology developed in the attached report for evaluatingi' chorage of subcomponents at the Palisades Plant. It should be noted th switchgear lD is considered to be representative of medium voltage swit
~ ear at the plant. The methodology developed in the attached report was extended as required for additional anchorage configurations and for additional bolt diameters.
In all cases, the anchorage of devices in switchgear lD was found to be acceptable.
An investiga-tion of the control room resulted in the identification of Control Room Panels C-11, C-llA, C-12, C-13, C-04, C-06 and C-126 as safety-related control panels.
In addition to the safety-related control panels in the control room, there exists safety-related Control Panel C-33 located at elevation 590'-0 of the auxiliary building
- Panel C-llA has been recently added in the control room and has been qualified separately. The results of the qualification,
(:J+however, are not incorporated in the attached evaluation report.
)f' In addition to evaluating anchorage of devices, the components in safety-related cabinets outside both the control room and the containment were checked to ensure that anchor devices (ie, bolts and screws) were in place as required by the original construction specifications.
The component check revealed all anchor devices to be in place.
OC0183-0005A-NL02
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.. DMCrutchfield, Chief Palisades Plant SEP Topic III-6 January 18, 1983 Ji1 I
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"{he neftlainiiiig* control room panels (~~ safety-relatea.lanels C-11, C-12, C-13, \\.c-04,and C-06) were part of an earlier study by URS/John A Blume to ensure stability of safety-related electrical equipment at Palisades.
These panels were provided with additional base support plus bracing from the top of the control panels.
Such support arrangement results in higher natural frequencies, lower response accelerations and therefore, lower stresses in the control panel structures.
Although Consumers Power Company has not performed a rigorous stress analysis for structural integrity of control room panels for the Palisades Safe Shutdown Earthquake (SSE), structural integrity of the control room panels is adequate due to their two-point support *. This conclusion is also substantiated by the results of an evaluation conducted by EQE, Inc entitled "Program For The Development Of An Alternative Approach To Seismic Equipment Qualification", which indicated that adequately supported electrical equipment has proven not to be a problem during an earthquake event.
Control Panel C-33, located at elevation 590'-0 of the Auxiliary Buildini°:fs supported only at its base. Since MCC 1 & 2 are supported only at the ba~ and they are located at a higher elevation which exposes them to higher accelera-tions, it was determined that MCC 1 & 2 represent the worst case for the structural integrity issue. It was, therefore, concluded that since the results of the enclosed report show MCC 1 & 2 to be structurally adequate, Control Panel C-33 is also expected to be capable of withstanding the Palisades SSE.
The issue of anchorage of subcomponents in the control panels and structural integrity of Control Panel C-126 remains to be addressed.
Control Panel C-126, which is supported only at its base, contains safety-related temperature and pressure indicators and contrg~:flwitches for hydrazine addition.
Consumers Power Company expectsvefaruations of these remaining items will show adequate seismic resistance based on our experience to date.
It is expected that these evaluations will be completed by July 1, 1983.
Kerry A Toner (Signed)
Kerry A Toner Senior Licensing Engineer CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades OC0183-0005A-NL02