ML18032A739

Procedure BFN 50 C 7100, Detailed Design Criteria for Structural Acceptance of Drywell Access Platforms.

ML18032A739
Person / Time
Site:	Browns Ferry
Issue date:	03/10/1988
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML18032A738	List: ML18032A737 ML18032A739
References
BFN-50-C-7100, TAC-00301, TAC-301, TAC-R00301, TAC-R00302, TAC-R00303, TAC-R301, TAC-R302, TAC-R303, NUDOCS 8803150306
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CRITERIA BFN 50 C 7100 ATTACHMENT F BROWNS FERRY NUCLEAR PLANT DETAILED Design Criteria For STRUCTURAL ACCEPTANCE OF DRYWELL ACCESS PLATFORMS NOTE: This Attachment incorporates and replaces BFN-50-790 Rev. 0 88<>>

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BFN-50-C-7100 Attachment F TABLE OF CONTENTS

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1.0 INTRODUCTION

~ ~ ~ 1 1.1 Descrxotion ~ ~ ~ 1 1.2 Pocooee ~ ~ ~ 1 1.3 Sco e ~ ~ ~ 1 2.0 DESIGN SPECIFICATIONS ~ . . ~ . . ~ ~ ~ ~ . ~ ~ ~ . ~ ~ ~ ~ ~ ~ ~ 2 3~0 LOADS AND LOADING COMBINATIONS ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 2 3.1 Loadin Definitions ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 2 3.2 Loadin Combinations ~ ~ ~ 5 4 ' DESIGN AND ANALYSIS PROCEDURES ~ ~ ~ ~ ~ ~ ~ ~ ~ , ~ ~ . ~ ~ ~ ~ 5 5 ' REFERENCES ~ ~ ~ ~ ~ ~ . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 5 Figure 3.1.7 Combination of Dynamic Reactions from Attached Systems Table 3.2.1 Loading Combinations For Stress Evaluations Table 3.2.2 . Loading Combinations For Uplift Evaluations

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BFN-50-C-7100 ATTACHMENT F i

1 0 INTRODUCTION The drywell access platforms include two main platforms, one at elevation 584 feet 11 inches, and one at elevation 563 feet 2 inches. The flooring is standard grating, with l-l/2-inch by 3/16-inch load bars. The grating and support steel extend from the reactor pedestal to the drywell shell at elevation 563 feet 2 inches and from the sacrificial shield wall to the drywell shell at elevation 584 feet 11 inches.

The platforms are supported by 24"inch-deep, wide"flange beams radiating from the reactor pedestal and sacrificial shield wall to the drywell shell. The radial support beams for elevation 584 feet 11 inches are field-welded to header beams in the sacrificial shield wall. The radial support beams Eor elevation 563 Eeet 2 inches are field-bolted to embedded plates in the outside Eace of the reactor pedestal. All radial beams are supported by beam seats welded to the drywell shell. Lubrite pads under,<he radial beams allow drywell shell expansion. Shear bars welded to the bottom flange of the radial beams on both sides of the beam seat prevent lateral movement of the beams. Intermediate grating support beams at 6 feet 6 inches maximum spacing are framed between the radial beams. Additional support beams are framed between both the radial and grating support beams for equipment, HVAC, cable tray, and piping system load attachments.

V 1.2 ~Pur ose The purpose of, this criteria is to establish the requirements Eor the designer to assure uniformity in design during the evaluation of the drywell access platforms and to obtain a safe and complete design considering all appropriate loading combinations. This criteria defines the loads and load combinations Eor use in this evaluation and also the associated 'allowable stresses and uplift evaluation requirements.

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1.3.1 The requirements of this document shall apply only to the structural steel inside the drywell at eLevation 5&4 feet 11 inches and elevation 563 Eeet 2 inches as denoted on TVA drawings 48N442 and 48N443, including miscellaneous steel for these elevations as denoted on TVA drawings 48N1015-series, 48N1016-series, and 48N1028.

1.3.2 In the event of conflicting requirements between this document and any reference material, this document shall govern. However, the civil project engineer shall be notified of the difference.

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BFN-50-C-7100 ATTACHMENT F 2.0 DESIGN SPECIFICATIONS For this structural design or reevaluation, the 1978 A1SC Specification for the Design, Fabrication, and Erection of Structural Steel for Buildings shall be used.

3.0 LOADS AND LOADINC COMBINATIONS 3.1 Loadin Definitions 3.1.1 D - Deadload, including structural steel, permanent equipment, and attached systems, e.g., piping, HVAC, cable trays, etc, shall be a minimum of 40 psf.

3.1.2 Lo - Outage and maintenance loads, including any moveable equipment loads and other loads which vary with intensity and occurrence during an outage, i.e., these loads will not be present while the plant is operating. An Lo of 100 psf applied to the loadable open areas 'hall be evaluated as a baseline outage and maintenance live load for the initial analysis using this criteria, As concentrated live loads due to outage or maintenance procedures are identified, these loads shall be evaluated against the baseline case. If the results of the concentrated loads exceed the baseline case, the concentrated loads must be evaluated per this criteria. The cooler live load shall be 1.5 kips per foot of beam, ~here applicable.

3.1.3 L Live loads while the plant is operating, including any loads which vary with intensity and occurrence and are not otherwise accounted for. For the purpose of the initial evaluation using this criteria, L will .be assumed aero.

3.1.4 E - Loads due to effects of OBE on structural steel and permanent floor"mounted equipment. This excludes support loads from attached piping, HVAC ducts, and cable trays (these loads are defined in Section 3.1.8) ~

3.1.5 E' Loads due to effects of SSE on structural steel and permanent floor"mounted equipment. This excludes support loads from attached piping, HVAC ducts, and cable trays (these loads are defined in Section 3.1.8).

3.1.6 Yr Equivalent static load on the structural due to a pipe whip reaction from existing pipe rupture restraints attached to the drywell steel.

Note: The application of pipe rupture loads only at those locations where mitigation exists is consistent with the baseline approach to pipe rupture design inside the drywell. Only those locations where GE and/or TVA negotiated pipe rupture mitigation as part of the original design need be considered.

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0 BFN-50-C-7100 ATTACHMENT F RPE Restraint of free end displacement loads, e.g., thermal reactions from attached piping systems based on the most critical condition.< RFE loads can be subdivided as follows:

3.1.7.1 RFEul RFF. reactions which contribute to uplift.

3.1.7.2 RFEs All other RFE reactions, i.e., reactions whicn do not contribute to uplift.

-If reduced conservatism is needed, RFE loads may be divided into upset, emergency, and faulted conditions corresponding to the associated dynamic loading conditions.

DYNB, DYNC, and DYND - Reaction of attached systems, e.g.,

piping, HVAC, cable trays, etc., due to upset (service level B),

emergency (service level C), and faulted (service level D) dynamic events, respectively. Note: Not all attached systems are anal.yred for the faulted condition', therefore', some reaction po'ints on the floor steel will only have upset and emergency loading.

3.1.8.1 Dynamic Reaction Phasing Dynamic reactions from attached systems are transmitted to the floor steel. through rigid restraints and snubbers. Based on 'the location and orientation of these restraints, different assumptions can be made regarding the phasing of these dynamic loads. These assumptions can be grouped into three general categories as follows:

Group A - Phasing Known Mhen two or more dynamic restraints act together to restrain particular motion or mode of vibration of an a

attached system, in-phase reaction loads can be assumed. For example, reactions resulting from a matched pair of vertical snubbers on a piping system would fall into this group.

Group B Random Phasing Mhen a dynamic restraint acts independently to rest'raj,n a particular motion or mode of vibration of an attached system, this reaction can be considered randomly phased with other dynamic reactions.

Group C Morst, Case Phasing Mhen two or more dynamic restraints act to restrain a particular location of an attached system in more F-3

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BFN-50-C-7 100 ATTACHMENT F one direction, a phasing relationship for these restzaints cannot be assumed. For example, two snubbers which restrain essentially the same point on a piping system and ~hose lines of action are skewed to each other would fall into this group. The results of these reactions must be sumned absolutely to determine an enveloping condition.

If fuzther justification or additional analysis can show a phasing relationship between group C restraint loads, these restraints can be treated as group A restraints.

3.1.8.2 Pzocedure for Determining DYNB, DYNC, and DYND 3.1.8.2.1 As a minimum, the following procedure shall be used to determine 'the dynamic reaction load cases.

A. Assign each dynamic reaction to one of the groups defined above. This will require engineering judgment.

Justification for these groupings should be included as part of the analysis report as required by section 4.0 of this criteria.

B. Gz'oup A reactions should be arranged into load sets per the phasing sssumed. Each load set should be evaluated separateLy with the results of each evaluat-ion constituting a dynamic load step.

C. Each group B reaction should be evaluated separately with the results of each evaluation constituting a dynamic load step.

D. Group C reactions should be arz'anged into load sets per their potential for phasing. Each reaction in the load set should be evaluated separately.

The absolute summation of the results of each reaction in the'oad set will constitute a dynamic load step.

E. Combine all dynamic load steps using the square root of the sum of the squares (SRSS) method to form DYNB, DYNC, or DYND.

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BFN-50-C-7100 ATTACHMENT F 3.1.8 2 2 Figure 3 1.7 provides a summary of procedure.

F 3.1.9 DYBD Larger of DYNB or DYND. To determine DYBD, screen each DYNB load step against the corresponding DYND load step. (Note that in some instances no DYND load step exists. In these cases, use the DYNB load step.) Combine the screened load steps using the SESS method to form DYBD.

3.1.10 DYCD - larger of DYNC or DYND. Use the procedure outlined in 3.1.9 above substituting DYNC for DYNB.

3.1.11 To " Thermal effects and loads during startup, normal. operating, or shutdown conditions, based on the most critical transient or steady-state condition.

3.1.12 Ta Thermal loads under thermal conditions generated by the postulated pipe break accident and including To.

3.2 Loadin Combinations As stated in section 1.1, all radial platform support beams are supported on one.end by beam seats. welded to the drywell shell. Since the beam seats do not have holddown capability, the potential for lifting off the beam seats as well as-the beam stress must be evaluated. Tables 3.2.1 and 3.2;2 detail the loading combinations which must be addressed in these two evaluations.

4.0 DESIGN AND ANALYSIS 'PROCEDURES The design and analysis procedures utilized for, the drywell steel structures, including assumptions on boundary conditions and expected behavior under loads, shall be in accordance with the AISC "Specification for the Design, Fabrication, and Erection of Structural Steel for Buildings," 8th Edition.

A summary of analysis procedures as well as justification for assumptions should be documented in the form of an analysis report. This analysis report should be issued's an OE calculation.

5 ' REFERENCES 5.1 Design Criteria BFN"50"D707, Revision 2, Analysis of As-Built Piping Systems.

5.2 Design Criteria BFN-50-D706, Revision 1, The Torus Integrity Long-Term Program.

5.3 TVA drawings 48N442, 48N443, 48N1015"series, 48N1016-series, and 48N1028.

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BFN-50-C-7100 ATTACHMENT F J

GROUP K +K K + K

'KN + KN+1 GROUP B DYNB SRSS DYNC Rl ~

DYND Rg RN GROUP C Ul + Ug U3 + Ug U'N + UN+1 Ki Individual group h reaction Ri Individual group B reaction Ui ~ Individual group C reaction Figure 3.1.7

.Combination of Dynamic Reactions from Attached Systems F-6

BFN-50-C-7100 ATTACHMENT F TABLE 3.2.1 LOADING COMBINATIONS FOR STRESS EVALVATION Combination Allowable Stress(

A. D + Lo 1.0 S B~ D+L+ E+ DYNB 1 0 S C~ D + Lo + E + DYNB 1.0 S D. D + L + E + DYNB + To + RFEs 1 ' S D + Lo + E' DYNC 1.6 S F~ D + L + E + DYNC + To + RFEs 1.6 S "

G. D + L + DYND + Ta + RFEs 1.6 S D + L + E + DYBD + Ta + RFEs + Yr (2) 1.6 S D + L + E I + DYCD + Ta + RFEs + Yr (2) 1 ' S Notes:

S - For structural steel, S is 'the required section strength based on elastic design methods and the allowble stresses defined in Part 1 of the AISC "Specification for the Design and Fabrication, and Erection of Structural Steel for .Buildings."

The one-third increase in allowable stresses due to the seismic or wind loadings is not permitted.

I (2) Only one pipe whip reaction should be considered at any given time; however, all postulated breaks 'for which pipe rupture mitigation structures exist and are. attached to drywell steel must be considered.

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BFN-50-C-7100 ATTACHMENT F TABLE 3.2.2 LOADING COMBINATIONS FOR UPLIFT EUALUATION~

Combination Static Loadin D namic Loadin

.9D + To + RFEul

.9D DYNB + E C .9D + To + RFEul DYNB + E

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.9D DYNC + E' 9D + To + RFEul DYNC +

E+ Yr E'YND+

.9D + Ta + RFEul

.9D + Ta + RFEul DYND + E' Yr Note:

(1) In each combination, it must be shown that the magnitude of the beam seat reaction due to static loading is greater than the-reaction due to dynamic loading, unless an adequate tiedown exists or the magnitude of uplift is within acceptable limits'hose acceptable uplift limits will .be defined on a case-by"case basis and included in this criteria if the need arises'-8

BFN-50-C-7100 Attachment F BFN-50-C-7100 DISCREPANCIES

1. '/R CEB-JMH-1060 (3FG 1013) statement that building will be designed to remain elastic under DBE appears to conflict with Table 4.2-33 which permits strength design instead of working stress design.

2. FSAR Section 12.2.2.7.3 states in 2 locations (TLM 1205 and 1206) that the ASME BSPV Code,Section III, Class B Vessels, 1968 edition was used, whereas Attachment D to BFN-50-C-7100 specifies the 1965 edition.

3. Source document for Section 3.1.1.D of BFN-50-C-7100 Attachment F for dead load was not consistent with FSAR Section 12.2.2.7.1; however, it was t d b y G/C. Also source document for Attachment F, Section 3.1.2 did incorporate not address cooler live load as provided in FSAR Section 12.2.2.7;1. . Ithasalso been added by G/C.

4, Table 4.2-14 of C-7100 {formerly FSAR Table 12.2-16) conflicts with Table 3.2.1 of Attachment F. This must be resolved in Revision 1 of C-7100.

5. FSAR Section 12.'2.2.7.1 (page 12.2-31) states that seismic load factors are applied to dead loads and live loads. Attachment F (source document BFN 709) implies seismic accelerations are only applied to dead loads.

6. Attachment F (formerly BFN-50-790) provides design criteria for uplift evaluations but makes no ment/on of tie-down columns as referenced in FSAR Section

' 12.2.2.7.1 (p. 12.2-31). This discrepancy is noted; however, the general ments in Attachment F should be adequate without any clesign requiremen cl reference to tie-down columns which may not even be re require unbred..

7. The one hour rainfall of 2.12 inches in Section 3.3 of C-7100 conflicts with the 14 inches cited in Attachment E, Section 4.2.5, for the Volume Reduction and

'olidification Structure.

8. FSAR Section 12.2 4.2 states that anchor bars for the chimney foundation shall consider ground saturated to El. 561.0 which corresponds to the maximum probable flood elevation. This conflicts with C/R CG-1023 which states that the MPF is El. 562-0.

The seconda containment internal positive design oressure of 7 inches o f ut in GECRNR1055' {845860618882) and incorporated into Attachment D does not agree wit F SAR 5 e etio ion 14443 hi h ifi I of 2 inches of water.

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