ML20148F150
| ML20148F150 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/15/1987 |
| From: | TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | |
| Shared Package | |
| ML17303B208 | List: |
| References | |
| RTR-NUREG-0797, RTR-NUREG-797 DAP-EP-057, DAP-EP-57, NUDOCS 8803280078 | |
| Download: ML20148F150 (5) | |
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COMANCHE PEAK OESIGN ADEQUACY PROGRAM ENGINEERING EVALUATION COVER SHEET TITLE Review of Cale. GENX 042 EVALUATION ID.NO.DAP-E P
_Q12_
NO. OF SHTS.
S DAP DISCIPLINE:
Pioina and Sueoorts DAP ACTION PLAN NO.
IX SUPPORTING ENGINEERING EVALUATIONS:
CONT.ID.NO. DAP-E-TITLE:
DAP-E-TITLE:
DAP-E-TITLE:
DAP-E-TITLE:
SUPERSEDES ENGINEERING EVALUATION NO. DAP E-PURPOSE: Evaluate and document the DAP review Stone and Webster's calculation No.15454-NZ(c)-GENX-042, titled Justification of the Design Load for Strut / Snubbers and Lugs Used in Conjunction with Riser Clamp.
SCOPE:
Review of calculation No.15454 NZ(c)-GENX-042 CONTENTS (SEE SECTION 4.0, DAP-8) t 1.0 ABSTRACT 2.0 REVIEW PROCESS l
BASES FOR SAMPLE SELECTION (Not Applicable) 3.0 REFERENCE DOCUMENTATION t
4.0 ACCEPTANCE CRITERIA 5.0 EVALUATION
6.0 CONCLUSION
S 7.0 ATTACHMENTS REVIEWE0 APPROVE 0 REV.NO.
REVISION ORIGIRATOR DATE
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1.0 ABSTRACT The purpose of SWEC calculation 15454-NZ(c)-GENX 042 is to provide a techni-cal basis for design load distribution between two parallel struts / snubbers used in conjunction with riser clamps.
It also determines the design load for shear lugs used in the above configurations.
It provides a basis for the modeling of eccentric supports. This engineering evaluation has determined that the SWEC calculation meets the third party acceptance criteria, and the conclusions of the calculation are correctly incorporated into SWEC procedure CPPP-7.
2.0 REVIEW PROCESS
2.1 Scope
The entire calculation was rev'iewed.
2.2 The calculation was reviewed for methodology and an independent numerical check was performed to verify the results.
2.3 Acceptance Criteria are defined in Section 4.0.
The calculation was evaluated against these criteria.
c 2.4 SWEC procedure CPPP-7, Rev. 2 (Reference 3.2) was reviewed to verify accurate implementation of the results of this calculation.
2.5 The conclusions are presented in Section 6.0 3.0 REFERENCE DOCUMENTATION 3.1 SWEC Calculation 15454 NZ(C)-GENX-042 titled, "Justification of the Design Load for Strut / Snubbers and Lugs Used in Conjunction with Riser Clamp," Rev. 1.
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s 3.2 SWEC Project Procedure; Design Criteria for Pipe Stress and Pipe Sup-ports, CPPP-7, Rev. 2 3.3 Additional references specific to the calculation are identified on page five of Reference Calculation 15454-NZ(c)-GENX-042.
4.0 ACCEPTANCE CRITERIA 4.1 09a1 strut / snubbers are designed with sufficient capacity to compensate for uneven loading conditions.
4.2 Local stresses are calculated based on the assumption that the total load is restrained by no more than half the total number of lugs in conformance with standard industry practice.
5.0 EVALUATION 5.1 The calculation was reviewed for methodology and an independent numerical check was performed to verify the results.
5.1.1 The calculation provides technical justification for load dis-tribution between dual strut / snubber supports using riser clamps.
The design load for each strut / snubber is to be based on 75 per-cent of total design load. The design basis of 75 percent is developed from a geometric model, which assumes only one pair of lugs makes contact with the clamp. A load distribution is calculated using simple statics. The resulting distribution (75:25) is conservative in that no credit is taken for the other lugs or for the "moment connection" between the clamp and pipe.
The calculation does not consider the effects of differential snubber lock up; however, given the conservatism noted above, the design basis of 75% of total load is considered reasonable.
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p 5.1.2 The design load for lugs used in conjunction with a riser clamp and dual strut / snubber assembly is to be based on each of the four lugs carrying half the total load. This approach is considered acceptable as it is in conformance with standard industry practice.
5.1.3 It should be noted that the static equilibrium formulas are based on a specific "standard" configuration.
If the as-built con-figurations differ from this "standard" configuration, the assumptions for load distribution should be changed accordingly.
5.2 The calculation develops a criterion for evaluation of dual strut /
snubber supports based on stiffness. For configurations where both sides are less than minimum stiffness (Km) and are not similar, one strut / snubber is physically removed and the support is modeled as an eccentric translational restraint. This is considered acceptable as the support has only one effective strut / snubber and the normal) represents the analytical model.
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5.3 The calculation develops criteria for modeling of eccentric supports in piping analyses where the support eccentricity is due to removal of one strut / snubber following a stiffness evaluation - as noted in 5.2 above.
For eccentric supports, the design load for each component support is to be the total design load. The design load for each lug is given by a formula developed in the calculation based on static equilibrium and This formula is considered acceptable as it is r
based on fundamental priaciples of statics.
(Note that on page 20, numerical errors appear in the formulation of the problem. These errors arise from transcription and do not affect calculation results.)
4 5.4 SWEC procedure CPPP-7, Rev. 2 (Reference 3.2) was reviewed to verify accurate implementation of the results of this calculation. Sections 3.10.6.2, 3.10.6.7 and Attachment 3-11 give guidelines for modeling support eccentricities in piping analysis. Section 3.10.8 and Attach-ment 4-18 give guidelines for assessing pipe support stiffness.
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- -8 implements calculation results.
Table 4A and 48 of -8 list maximum allowable stiffness ratios between support structures. Section 2.1 of Attachment 4-8 gives criteria to determine design loads for lugs used in conjunction with riser clamps.
6.0 CONCLUSION
S 6.1 SWEC calculation 15454 NZ(c)-GENX 042 meets the acceptance criteria, SWEC procedure CPPP-7, Rev. 2 provides proper implementation of this calculation.
7.0 ATTACHMENTS None.
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