ML18052A965
| ML18052A965 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 04/30/1987 |
| From: | Kuemin J CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML18052A966 | List: |
| References | |
| RTR-NUREG-CR-1833, TASK-03-06, TASK-3-6, TASK-A-46, TASK-OR, TASK-RR NUDOCS 8705040193 | |
| Download: ML18052A965 (13) | |
Text
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consumers Power POWERINli NllCHlliAN"S PROliRESS General Offices: 1945 West Parnell Road, Jackson, Ml 49201 * (517) 788-0550 April 30, 1987 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
SEP TOPIC III-6, SEISMIC DESIGN CONSIDERATIONS -
RESOLUTION OF OPEN ISSUES Consumers Power Company letter of January 21, 1987, discussed the unresolved issues pertaining to SEP Topic III-6 in response to an NRC request of October 20, 1986.
In our letter, we committed to the use of the NUREG/CR-1833 response spectra and to resolution of the electrical cable tray issue during implementation of the Unresolved Safety Issue A-46.
The NUREG/CR-1833 response spectra has been used in the enclosed evaluations while the cable tray issue will be resolved as per our commitment.
Consumers Power Company also committed to providing information on out-of-plane vibration of floors and masonry walls and the structural integri-ty of electrical cabinets.
The attachments to this letter provide the information for resolution of these open issues as follow:
Attachment A, Out-of-plane vibration of Palisades Plant masonry walls Attachment B, Palisades Floors Flexibility Attachment C, Control Room Panel C-126 Attachment D, Control Room Panel C-llA Attachment E, EQE Report on Motor Control Centers 1 and 2; Control Panel C-33; and Switchgear Cabinet lD In C-33 control panel evaluation suggests that resolution is dependent upon physically connecting the panel to an adjacent panel to eliminate the poten-tial interaction between the panels which could result in structural failure.
Consumers Power Company commits to completing this modification by the end of the next refueling outage.
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We also note that in conjunction with future implementation of unresolved Safety Issue A-46, Consumers Power Company will reevaluate the hot-shutdown electrical cabinets noted above, as well as other equipment required for hot shutdown, to verify their seismic adequacy.*
In suuunary, resolution of the*seismic response spectra, cable tray issue (via USI A-46) out-of-plane vibration of floors and walls, and structural integrity of electrical cabinets (including our couunitment to modify C-33 control panel) have been provided to complete the open issues related to SEP Top~c III-6 *
/.~
~Kuemin Staff Licensing Engineer
- CC Administrator, Region III, NRC NRC Resident Inspector - Palisades OC0487-0048-NL02
ATT0487-0048-NL04*
ATTACHMENT A Consumers Power Company Palisades Plant
- Docket 50-255
. OUT-OF-PLANE VIBRATION OF PALISADES PLANT MASONRY WALLS April 30, 1987 1 Page
Page 1 of 1 A.TTACHMENT_ A OUT-OF-PLANE VIBRATION OR PALISADES PLANT MASONRY WALLS The masonry walls at the Palisades Pl~nt were evaluated under the auspices of I E ~ulletin 80-11.
CP co provided responses to the Staff on July 9, 1980 in a letter from D P Hoffman (CP Co) to J G Kepler (NRC) and on November 8, 1980 in a letter from B.D Johnson (CP co) to D M Crutchfield (NRC).
The letter of November 8 transmitted a re-evaluation criteria to the Staff.
se~tion 6~A of that design criteria for re-evaluation posed a maximum wall
- deflection criteria for stability analysis of 0.3 times the wall thickness.
That same section of the criteria explicitly st~ted that a determination would be made as to whether or not the total displacement of the wall would adversely-impact the function of equipment attached to the _wall~ The evaluation criteria did not indicate a requirement for a system/subsystem.*
(wall/attac~m~nt} interaction analysis designed to evaluate the dynamic amplification of acceleration which might be. introduced into the wall attacbment.
Some basic interaction assumptions were made for the purpose of bounding applied wall loads.
Some 73 walls were evaluated under the I E Bulletin effort.
Approximately 41 of those walls were repaired.
Repair typically consisted of either: moving safety related equipment from the proximity of the wall, adding large angles at the boundaries of walls so as to erisure a pinned boundary condition or running channel from top to bottom or from one side to the other of the wall so as to limit flexural stresses or displacements~
_Analysis summaries and 1980 photographs were reviewed for all of the walls for which they were available.
For most of the walls, safety related equipment was in proximity rather than attached to the walls.
Most of the equipment attached to the walls was piping.
Junction boxes and other electrical devices which were affixed to the walls tended to be at the side of the walls.
The photographs revealed no acceleration-sensitive devices attached to central regions of masonry walls.
None of the piping attached_ to th~ walls in the..
photographs was judg~d to be vulnerable to the potential displacements imposed at support points.
Ten of the walls were recently walked down and rephotographed~ The conclusion for these walls was the same.
That is~ no equipment on these very.lightly-loaded walls is vulnerable to wall_-
acceleration or displac~ment. The twd walls in containment-not initially photographed under the I E Bulletin program were n6t walked down for respons~
to this SEP topic.
The data record indic~tes that these walls support. pipe if t_hey support any equipment at all *.. Base_d _upon-a review of the other walls along with the design criteria for re-evaluation, it was concluded that these walls should pose rio concerns with regard to imposing exces~ive loads 6n the attached equipment.
Doc ID 0825E G009A
ATT0487-0048-NL04 ATTACHMENT B Consumers Power Company Palisades Plant Docket 50-255 PALISADES FLOOR FLEXIBILITY.
April 30, 1987 2 Pages
Page 1 of 2 ATTACHMENT B PALISADES FLOOR FLEXIBILITY The NRC staff has requested CP co to investigate the issue of floor flexibility with respect to its influence on equipment anchorage and structural integrity.
Floor flexibil~ty has the potential for a significant contributiuon to overall seismic response of equipment when the USNRC Regulatory Guide 1.60 earthquake floor spectra are employed.
The Regulatory Guide 1.60 spectra for Palisades are depicted in NUREG/CR 1833.
NUREG/CR 1833 shows the vertical response spectra to be of similar magnitude to the horizontal response spectra.
In the original Palisades Plant seismic design criteria, the horizontal seismic response spectra strongly dominated the ve~tical spectra.
Therefore, floor flexibility was not generally explicitly accounted for in the assessment of equipment response to seismic loadings.
The assessment of the C-126 panel by Stevenson and Associates* was one Of the anchorage assessments where*the floor frequencywas estim~ted and the spectral ordinate was used to amplify the seismic input to:the cabinet structure.
In order to assess the potential for floor flexibility, drawings were reviewed.
The civil drawings were scanned for large, relatively unsupported, thin concrete slabs loaded with heavy equipment.
It was concluded that the 12 inch slab supporting the control room equipment and the 12 inch slab floor of the cable spreading room were_ controlling from the perspective of floor flexibility.
Each of these floors had the following characteristics:
0 0
0 0
0 0
12 inches thick approximately 48 feet by 48 feet supported somewhat near the center by a concrete column spanned underneath in one.direction by a concrete member loaded with heavy equipment supporting safety related equipment It was c6ncl~ded that the dynamic characteristics of these two floors were very ~imilar. Therefore, the control room was selected for a detailed assessment bf out-of-plane floor flexibility becau~e it was representative of the cable spreading room floor and because it supports cabinets c-llA and c-126 which still constitute open items with regard to SEP Topic III-6.
Th~
intent of the detailed assessment was to create an out-of-plane seismic acceleration map of the control room floor.
This map could also yield inferences with regard to the accelerations anticipated at equipment locations in the cable spreading room located directly below.
IMPELL corp was retained by CP co to conduct the analysis of the control room floor.
A walkdown of the plant area was conducted and equipment locations were located and equipment weights were recorded.
A finite element model (SAP) of the control room was constructed.
A total of 176 plate elements defined by 204 model node points were employed to define the slab.
A 175 pounds per square foot (PSF) general floor loading was employed in the main area with a 200 PSF loading being employed in the office area.
Equipment mass
. was distributed as lumped weight around the outer edge of the eq~ipmen~.
Doc ID 0825E 0009A
- e.
Page 2 of 2 ATTACHMENT B (-cont Id-) -
The IMPELL model considered a column from grade level as a vertical deflection boundary condition.
This column is near the cente~ of the floor.
The model
~!so considered a deep beam which ~uns north-south near the center of the floor as an influence in section stiffness. Analysis was conducted for two
~~ti of floor slab end coriditi6ns._ A lower*bound_of.frequency was simulated by pinned-pinned boundary conditions.
A more realistic assessment was conducted with calculated joint stiffness *
. A response ~pectra arialysis was conducted_ on th~ model with both sets of edge boundary conditibris~ The vertical input spectrum vas that of NUREG/CR 1833 for 7 percent damping.
The response of the individual modes was combined bi USNRC Regulatory Guide 1.92 with closely spaced modes.
The zero period acceleration for this spectra is.28g and the peak is appr6ximately 1.209 at
.7.0 HZ.*
For the boundary condition of the pinned edge, the fundamental floor £requency was determined to be 9.5 HZ.
The first mcide dominated ali modes and yielded over 95 percent of the total re.sponse at all nodes.
The spectral ordinate at 9.5 HZ is.97g.
The maximum aciceleration at any node point was l.38g which represents an amplification_ of the spectral ordinate of approximately 1.42.
The seismic SSE ~ertical acceleration at the centei of the panel c-llA is
- 0. 86g.
The acceleration* at the center of panel C-126 is 1.039*. _
For the boundar~ conditiori of joint stiffness, the fundament~l floor frequency was calculated to be 11.5 HZ.
This results in a spectral ordinate of.80g, a maximum acceleration of 1.149, a c-llA acceleration of.7lg and a c-126 acceleration of
.85g~
~hese latter accelerations are judged suitable for ah evaluation of equipment anchorage or structural integrity.
The acceierations calculated for the control room floor should bound those of the cable spreadin~ roo~ floor which supports MCC-1 and _MCC-2.
Although the floor has the same span size, supporting column and floor thickness, the cable spreading room floor_is supported by an underside wall which essentially divides the floor in half.
In the cont~ol room,_ the underside.of the floor.
was supp~:>rted by a stiff beam.
The MCC layout is perpendicular to and is bisected by the underside wall.
Thus, the cable spreading room floor should be. stiffer than the control room floor and impart less seismic acceleration
_ response to the equipment supported on it.
Doc ID 0825E 0009A
ATT0487-0048-NL04 ATTACHMENT C
.Consumers Power Company Palisades Plant Docket 50~255 CONTROL ROOM PANEL C-126 April 30:. 1987 2 Pages
Page 1 of 2 ATTACHMENT C CONTROL ROOM PANEL C-126 A.
panel Structural Integrity and Base Anchorage Adequacy An equivalent static analysis was performed to qualify this panel by Stevenson & Associates in 1984.
Two load cases, the vertical acceleration plus dead load applied simultaneously to each of the horizontal accelerations, were evaluated.
The vertical and horizontal accelerations were 0.3g and 2.76g respectively.
These accelerations were based on the original Palisades Plant design criteria.
The 0.3g is two-thirds.of the 5% damping ground horizontal spectral acceleration value at the calculated control room floor natural frequency of 7.5 Hz, multiplied by a plate (floor) amplification factor of 1.62.
The 2.76g is obtained by applying a 1.5 factor to the peak spectral acceleration for the 625 ft elevation of the auxiliary building with 5% damping.
The stresses calculated were compared to the allowable stresses obtained by applying a factor of 1.6 to the AISC.and AISI specification allowable stresses. Results indicate that all structural component stresses above the base are below the allowable stresses except.for the base.anchorage *.
Modifications to the base anchorage wer~ recommended by Stevenson &
Associates using.base angles and Red Head expansion anchors.
subsequently; the base anchorage modifications were installed in 1985 using Hilti expansion wedge type anchor bolts and base angles.
In 1987, CP co performed an evaluation on the panel and the.installed base anchorage modifications using the NUREG/CR-1833 accel~ration levels which were based on 0.2g R.G. 1.60 spectra.
The horizontal and vertical
- accelerations used in the evaluations were 2.22g and 2.03g respectively.
Th* horizontal acdeleratt6n was obtained by applying a factor of.1.5 td the 5% damping average p~ak spectral acceleration of El. 610 1-0*_ and El.
640 1 -0*~ The vertical acceleration was obtained using the 7% damping peak vertical spectral acceleration multiplied by a plate (floor).amplificat(o~
factor of ~.62. - The control panel was assumed to be rigid in the verticai direction while the concrete floor was assumed to be flexible.
The techniques and acceptance criteria used in the CP co evaluation were consistent with those in Stevenson & Associates' calculation. *The Hilti wedge type anchors were evaluated for shear and tension interaction using a ~afety factor of 4.
The results indi~ate that the control panel c-126 maintains structural integrity, and the modified base anchorage meet the requirements ~f the interaction acceptance criteria.
Doc ID 0816E 0009A
Page 2of 2 ATTACHMENT c (Cont'd)
- a. Subcomponent Anchorage In 1984, CP co perfoimed an equivalent static analysis evaluation on c-126 subcomponent anchorage using the original Palisades Plant response spectra.
Two load cases, the dead load plus the vertical acceleration applied simultaneously to each of the horizontal accelerations, were evaluated.
The horizontal accelerations used were 2.76g in the direction parallel to the panel face and 4.47g perpendicular to the panel face.
The vertical acceleration was 0.63g.
The horizontal acceleration parall~l to the panel face was obtained by applying a 1.5 factor to the 5% damping peak horizontal spectral acceleration at El. 625 1-0*.
The horizontal acceleration perpendicular to the panel.face. include* an additional plate amplification factor of 1.62.
The vertical acceleration was obtained by applying factors of 1.5 and 1.62 for plate amplification to the 5% damping ground horizontal spectral acc~leration at the calculated control room floor slab frequency of 7.5 Hz.
The calculated stresses were compared with the allowable stresses obtained by applying a factor of 1.6 to the AISC and AISI specification allowable stresses.
Re~ults indicate that all the subcomponent anchorage stresses are below the allowable stresse~.
In 1987, CP co re-evaluated the subcomponent anchorages using the 0.2g R.G.
l.60 acceleration levels shown in NUREG/CR 1833.
The horizontal accelerations parallel and perpendicular to the panel face were 2.22g and 3.6g respectively were used.
These accelerations were based on an a6celeration of l.48g whic~ is the average of the 5% damping peak s~ectral
- accelerations of El. 610 1-0* and El. 640 1 ~0* and the same factors (l.62 and/dr 1;5) as the original calculation.
The vertical acceleration used wa~ 3.04g which was.based on a 7% damping pea~ vertical spectral acceleration of l.25g and the same.factors (1.5 and 1.62) as *the original calculation.
The loading combinations and.the acceptance criteria were consistent with the original calculation.
The results* indicate that the anchorage stresses _
are below the allowable stresses.
Doc ID 0816E 0009A
ATT0487-0048-NL04 ATTACHMENT D Consumers Power Company
- Palisades Plant Docket 50-255 CONTROL ROOM PANEL C-llA April _30, 1987 2 Pages
Page 1 of 2 ATTACHMENT D CONTROL ROOM PANEL C-llA A finite element analysis using beam and plate elements was performed by Analytical Engineering Associates, Inc. iri 1982 to evaluate the structural integrity and anchorage adequacy of the panel~ The analysis established that the fundamental frequency is 18.2 Hz which is at the rigid range of the floor spectra at El. 625 1-0*. *A static analysis ~as subsequently performed to evaluate the stresses of the members.
The acceleration values used were 0.5g horizontal for both directions and 0.14g vertical.
These levels were obtained from the original.Palisades Plant floor responie spectra at El. !25 1-0*.
The stresses due to directional excitation were summed by taking the square root of the sum of the squares.
The stress summary and the allowable stresses used in the analysis are as follows:
Member/Material SSE + D.L.
Allowable Plate Stresses/A-36 Flexural 688 psi 32,400 psi Shear 637 psi 17,820 psi Welds shear stress/EGO or E70 Weld Size same as Plate Thickness 7,219 psi 22,275 psi Weld Size 3/4 of Plate Thickness.
9,626 psi 22,275 psi Section Interface Bolts SheariA-325 11, 980 psi 42,075. psi Mounting Anchor Bolts/
Shear and tension 1.0 or less 5/8* Diameter Hilti linear interaction using safety factor Of 4 = 1.0 Base Gusset Plate 10,601 psi 32,400 psi stress/A-36 Base Channel Flange 29,675 psi 32,400 psi Flexural Stress/A-36 Beam.combined Flexural &
4,448 psi 32,400 psi Axial/A-36 Doc ID 0816E 0009A
Page 2 of 2.
ATTACHMENT D 'cont'd)
The floor response spectra shown in NUREG/CR 1833 based on 0.2g R.G. 1.60 spectra are somewhat different from the original Palisades Plant floor-response spectra.
To determine the control panel stresses due to this new set of floor response spectra, CP Co performed a calculation in 1987 using 0.4159 horizontal excitation (both directions) and 2.03g vertical excitation.
The 0.415g is the average acceleration of the 5% damping spectral acceleration at El. 610' and El.640' at 18.2 Hz.
The 2.03g is obtained using the peak vertical spectral acceleration with 7% damping multiplied by a plate (floor) amplification factor of 1.62.
The control panel was assumed to be rigid in the vertical direction while the concrete floor was assumed to be flexible.
The techniques and acceptance criteria used in CP co calculation were consistent with those in the Analytical* Engineering Associates, Inc.
calculations and the CP co calculation was based on the data shown in the Analytical Engineeiing Associates, Inc. calculation.
- only the structural components which have the ratio of allowable stress to computed stress (Analytical Engin~ering Associate~, Inc. calculation) of 2.65 or less were evaluated.
The 2.65 number. accounts for the increase in vertical acceleration iri NUREG/CR-1833, and is:
lg (Dead Load) + 2.03g (Vertical Acceleration used based on NUREG/CR 1833) lg (Dead Load)+.14g (Vertical Acceleration per Original Palisades.plant Criteria) consequently, the welds, the base channel flange and the mounting anchors were evaluated in CP co calculation.
The results are:
Member/Material
\\
Weld shear stress/E60 or E70 Weld Size Same as Plate Thickness
- weld Size is 3/4 of Plate Thickness Mounting Anchors/
5/8* Diameter.Hilti Base Channel Flexural Stress/A-36_
SSE + D.L.
Less than 8,771 psi Less than 11,700 psi Shear & tension linear interaction using S~F. of 4 = 0.974 27,000 psi Allowable 22,300 psi 22,300 psi 1.0 or less 32,400 psi Based on the above analyses, the control Panel ell-A will survive a DBE with acceleration levels depicted in both the original Palisad~s Plant spectra and.
the 0.2g R.G. 1.60 Spectra.
DOC ID 0816E 0009A