ML20198R573
| ML20198R573 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/12/1998 |
| From: | External (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20198R540 | List: |
| References | |
| PROC-980112, NUDOCS 9801230349 | |
| Download: ML20198R573 (3) | |
Text
PIPING AND STRUCTURAL DESIGN REVIEW CRITERIA MILLSTONE UNIT 2 ICAVP a
The following guidelines are developed for performing the pipe stress, pipe support, and structur"I calculation for cable tray, conduit and duct supports resiews associated with the Tier 1 ICAVP for Millstone Unit 2. This design rniew process is similar to a design verification, with the exception that it will not be performed on a line-by-line basis. In addition to the review of calculations, a design rniew of respective design basis documenta will be performed against the applicable licensing basis.
f These guidelines will be implemented for all systems selected for the Millstone Unit 2 Tier i ICAVP, 1.0 PIPE STRESS CALCULATIONS 1.1 Large Bore (>2") Piping Stress Calculations A two-level proecss will be implemented for the design resiew oflarge bore piping systems. The first levcl resiew will be performed for the whole population to ensure that the design parameters, as documented by the calculations, are consis!ent with the applicable licensing and design basis criteria. The second level resiew will include 20% of all large bore pipe stress calculations. Of the 20% selected, half will be a random sample and the other half will be a smart sample.
The 10% smart sampic will be selected based on mineeringjudgment with consideration for:
(1) identification of the organization responsibit tr the calculation, (2) identification of common attributes between the calculations u hich will allow grouping, (3) identification of most critical calculations. (4) sections containing motor operated or air actuated valves which are supported by the pipe, and (5) consideration of system multiple train design. The second level review will verify the repetitive tasks of the computer analysis ponion of each calculation. Repetitive tasks are defined as modeling of the piping system, preparing the piping computer code input, performing the analysis and obtaining computer output, plus verifica' ion of the computed stress values against Code allowable stresses. This review will verify that the design information is correctly and accurately entered into the piping analysis computer code and that the computer output results support the conchisions of the calculation.
This two-level re icw process will prmide assurance that the large bore piping analysis qualifications will be subjected to a thorough design review In the event that less than 80% of the total population of pipe stress analysis calculations are supplied as complete packages (including computer outputs), the pew:ntage of calculations receiving a second level review will be increased to 30%. In addition, a Discrepancy Report (DR) will be written identifying the incomplete pipe stress calculations and the type of missing infonaation.
1.2 Small Bore (2" and under) Piping Stress Calculations A 20% random sample design resiew of small bore piping stress calculations containing computer analyses will be performed. A 20% random sample design review will be perfonned for field routed and suppor*cd small bore piping systems. A minimum of 3 small bore piping stress calculations and 3 field routed piping systems will be reviewed.
1.3 Tubing Stress Calculations A 10% random sample design review of the total number of tubing stress calculations and/or design d,cumentation will be performed. The sample will include one of each group of redundant transmitters that are used to initiate system operation.
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PIPING AND STRUCTURAL DESIGN REVIEW CRITERIA MILLSTONE UNIT 2 ICAVP 1.4 Vent and Drain Stress Calculatlans A 10*4 random sampic design resiew of the total number of vent and drain stress calculations and/or design documentation will be performed. The sample will include one of each interface type that is applicable to the system.
2.0 PIPE SUPPORTS In general, pipe supports fall into three categories, (1) component supports, (2) supports built cf structural steel, and (3) standard supports. Component supports cor.sist of pipe clamps with a spring, snubber,4 ut or other standard components from vendor catalogs with a structural stect or baseplate-to-concrete attachment. Structural steel supports are built-up box frames consisting of W-shapes or structural angle with U-bolts or straps. Component supports may be attached to structural steel framing. Standard pipe supports are generally provided in a design criterion with maximum loading: provided for small bore pipe and tubing.
2.1 Component Pipe Supports The qualifying calentations typically address the evaluaGon of standard components, welds to stal attachments and baseplates, local structral s*cci evaluations or anchor bolts to concrete, and other common characteristics. All pipe support calculations received will be screened and will be grouped by support t)pe, such as variable springs, snubbers, struts, etc. Within each group, supports will then be categcrin:d by parameters such as critical loading, thermal movements, stress, and geometri: configuration. Each group will then be screened and 20% of the total number of supports within cach group will be sciccted for design review. Of the 20%
selected, at least half eMc pipe support calculations will be based on a representative selection.
The representative sample will be based on the most critical support parameter and engineering judgment. In the event that less than 80% of the total population of support calculations is recited, a number of critical supports will t;e selected for independent evaluation. Some supports at pipe rupture locations will be included in the selected sample, if applicabic. This selection process is dec;ned sufficient due to the repetitive nature of the pipe support calculations.
A minimum of th ce (3) pi; apports from cach grouping will be reviewed.
2.2 StructuralSteelPipe Supports These calculations consist of the evaluation of the structural steel members, welds, local structural attachments, and/or anchor bolts to concrete. All support calculations received will be grouped, categorized, and a 20% population selected for design review as outlined in paragraph 2.1. A minimum of three (3) pipe supports from each grouping will be resiewed.
2.3 Standard Pipe Supports Each standard or typical pipe support configuration may be used multiple times within a piping subsystem. Each support calculation rc,ccived within the selected systems will be grouped, categorized, and a 20% population selected for design review as outlined in paragraph 2.1. A minimum of three (3) pipe supports from cach grouping will be resicwed.
2.3 Independent Pipe Support Evaluation in the event that a sufficient number of support calculations from the total population are not provided for review, a number of critical supports will be selected for independent evaluation.
This confinnatory analysis will evaluate both the original support design and the adequacy of the design for NRC Bulletin 79-02 requirements.
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PIPING AND STRUCTURAL DESIGN REVIEW CRITER)A MILLSTONE UNIT 2 ICAVP 3.0 TUBING SUPPORTS Each standar6 md non-standard tube support configuration may be used multiple times within a tubir.g system. Tubing supports configurations within the selected system boundaries will be grouped, categorized, and a 20% population chown fcr design resiew.. A minimum of three (3) supports from each grouping will be reviewed.
4.0 CONDUlT, CABLE TRAY AND DUCTWORK SUPPORTS Conduit, cable tray and ductwork supports designs were generated as standard and non-standard configurations. Corfigurations wit:dn the elected systems will be grouped and categorized.
Conduit and cable tray supports were included in the Millstone Unit 2 Generic implementation Program (GIP). A SQUG-type walkdown, based on the GIP criteria, will be pertormed on 20%
of the support population. In addition, a design resiew will be performed on the GIP limited analysis calculations of their selected worst case sample supports. Ductwork supports were not included in the GIP program. For ductwork supports, a design review of the design basis documents, generic support calculations, and 20% of the non-standard support calculations will be performed. In addition, a walkdown of 20% of the total ductwork support population will be performed.
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