ML19221A986
| ML19221A986 | |
| Person / Time | |
|---|---|
| Issue date: | 03/31/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-75-087, NUREG-75-087-03.3.1, NUREG-75-87, NUREG-75-87-3.3.1, SRP-03.03.01, SRP-3.03.01, NUDOCS 7907120133 | |
| Download: ML19221A986 (3) | |
Text
e arco NUREG 75/087 o
/' N v ','o U.S. NUCLEAR REGUL ATORY COMMISSION SW g
dis"p#3 ) STANDARD REVIEW PLAN OFFICE OF NUCLEAR REACTOR REGULATION SECTION 3.3.1 WIND LCADINGS REVIEW RESPONSIBILITIES Primary - Structural Engineering Branch (SEB)
Secondary - Hydrology-Meteoroloc,y Branch (HMB) l I.
AREAS OF REVIEW The following areas relating to the design of structures that h e to withstand the effects of the design wind
- specified for the plant are reviewed to assure confermance with the requirements of General Design Criterien 2.
1.
The design wind velocity and its recurrence interval. the velocity variation with height, and the applicable gust factors are reviewed from the standpoint of use in defining the input parameters for the structural design criteria appropriate to account for wind leadings. The bases for the selection and the values of these parameters are within the review responsibility of the Hydrology-Meteorology Bianch (HMB) as stated in SRP Sections 2.3.1 and 2.3.2.
2.
The procedures that are utilized to transform the design wind velocity into an effective pressure applied to structures are reviewed taking into consideration the gecmetrical configuration and physical :haracteristics of the structures and the distribution of wind pressure o structures a
II.
ACCEPTANCE CRITERIA The acceptance criteria for the areas of review are as follows:
1.
General Design Criterion 2 with regard to the design bases for protection of structures important to safety against wind loadings 2.
The acceptance criteria for the design wind velocity and its recurrence interval, the velocity variation with height, the applicable gust factors, and the bases for determining these site elated parameters, are established by the Hydrology-Meteorology Branch (HMf>) and are contained in SRP Sections 2.3.1 and 2.3.2.
The approved values of these parameters should serve as basic input to the review and evaluation of the structural design procedures.
l
- Referred to as 100 year return period " fastest mile of wind" in SRP Section 2.3.1.
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3.
The procedures utilized to transform the wind velocity into an effective pressure to be applied to structures and parts and portions of structures, as delineated in ANSI A58.1, " Building Code Requirements for Minimum Design Loads in Buildings and Other Structures" (Ref. 3), are acceptable. In particular, the procedures utilized are acceptable if found in accordance with the following:
I For a design wind velocity of V mph specified at a height of 30 feet above 30 the ground, the velocity pressure, q30, is given by:
30 0.002% q0 PSI q
The effective pressure for structures, qp, and for port %ns thereof, q, at various heights above the ground should be in accordanu with Table 5 and Table 6 of ANSI A58.1, respectively. Since most nuclear power plants are located in relatively open country, Exposure C, as defined in ANSI A58.1, should be selected for both tables.
Depending upon the structure geometry and physical configuration, pressure coefficients may be selected in accordance with Section E.4 of ANSI A58.l.
l Geometrical shapes that are not covered in this document are reviewed on a case-by-case basis. ASCE Paper No. 3269, " Wind Forces on Structures" (Ref. 2),
may be used to obtain the effective wind pressures for cases which ANSI A58.1 does not cover.
III. REVIEW PRJCEDURES The reviewer selects and emphasizes material frop the review procedures described below as may be appropriate for a particular case.
1.
The site-related parameters described in sabsection I.1 are reviewed by the Hydrology-Meteorology Branch (HMB) under SRP Sections 2.3.1 and 2.3.2.
The structural reviewer examines the approved values of these parameters to assure himself that the procedures utilized in designing the structures to withstand the specified wind loadings are appropriate and applicable.
2.
After the applicability of the site related parametcrs is established, the reviewer proceeds with the review of the structural aspects of wind design. The procedures utilized by the applicant to transform wind velocities into effective pressures are reviewed and compared with those procedures delineated in the ANSI A58.1 standard.
IV.
EVALUATION FINDINGS The reviewer verifies that sufficient information has been provided to satisfy the requirements of this SRP section, and concludes that his evaluation is sufficiently l
complete and adequate to support the following type of conclusive statement to be included in the staf f's safety evaluation report:
Rev. 1 3. 3.1 -2 146 0/0
"The procedures utilized to determine the loadings on structures induced by the l
design wind specified for the plant are acceptable since these procedures provide a conservative basis for engineering design to assure that the structures will withstand such environmental forces.
"The use of these procedures provides reasonable assurance that in the event of design basis winds, the structural integrity of the plant structures that have to be designed for the design wind will not be impaired and, in consequence, safety-related systems and components located within these structures are adequately protected and will perform their intended safety functions if needed. Conformance with these procedures is an acceptable basis for satisfying, in part, the requirements of General Design Criterion 2."
V.
REFERENCES I
10 CFR Part 50, Appendix A, General Design Criterion 2, " Design Bases for l
Protection Against Natural Phenomena."
2.
A5CE Paper No. 3269, " Wind Forces on Structures," Transactions of the American l
Society of Civil Engineers, Vol. 126, Part II (1961).
3.
ANSI A58.1, " Building Code Requirements for Minimum Design Loads in Buildings and l
Other Structures," Committee A58.1, American National Standards Institute.
146 071 3.3.1 -3 Rev. 1