Regulatory Guide 1.67
| ML13064A109 | |
| Person / Time | |
|---|---|
| Issue date: | 10/31/1973 |
| From: | US Atomic Energy Commission (AEC) |
| To: | |
| References | |
| RG-1.067 | |
| Download: ML13064A109 (2) | |
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October 1973 U.S. ATOMIC ENERGY COMMISSION
DREGULATO RY
DIRECTORATE OF REGULATORY STANDARDS
GUIDES
REGULATORY GUIDE 1.67 INSTALLATION OF OVERPRESSURE PROTECTION DEVICES
A. INTRODUCTION
For those pressure relief valve stations within its scope, ASME Code Case 1569, "Design of Piping for General Design Criterion I, "Quality Standards and Pressure Relief Valve Station," provides guidance that Records," of Appendix A, "General Design Criteria for may be used in the design and analysis of piping for a Nuclear Power Plants," to 10 CFR Part 50, "Licensing pressure relief/safety valve station. However, because of of Production and Utilization Facilities," reauires that the limited scope of the code case, the following structures, systems, and components important to safety additional guidelines should be employed:
be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the 1. Appendix B, "Owner's Design Specifications," of safety functions to be performed. This Regulatory Guide Section III of the Code indicates in paragraph B-1 223.2 describes a method acceptable to the AEC Regulatory that the' Design Specification should stipulate the loads, stalT for implementing Ihis criterion with regard to the the effect of which must be combined with the design design of piping for safety valve and relief valve stations pressure effects for comparison with the several primary which have open discharge systems with limited stress-intensity limits at the design temperature. Code discharge pipes and which have inlet piping that neither Case 1569 requires inclusion of the reaction force contains a water seal nor is subject to slug flow of water (including dynamic effects) among those loads to be upon discharge of the valves. This guide applies to compared to the primary stress-intensity limit.;.
light-water-cooled reactors. The Advisory Committee on Therefore, the magnitude 'of the reaction forces should Reactor Safeguards has been consulted concerning this be stipulated in the Owner's Design Specification, guide and has concurred in the regulatory position. including the anticipated transient behavior of the forces.
B. DISCUSSION
2. Subarticles NB-7300, "Overpressure Protection Pressure relief valves are required to be installed on Report," and NC-7300, "Overpressure Protection the reactor coolant system pressure boundary of nuclear Analysis," of the Code require submission of a power plants to provide overpressure protection. Failure documented analysis of the transient conditions and of the valve or piping to the valve, however, can operating conditions that give rise to the maximum constitute the equivalent of an open-ended rupture of relieving requirements. Therefore, for those systems the piping. where an overpressure report or analysis is required, the individuals preparing these documents should also The Working Group on Piping of the ASME Boiler evaluate, stipulate, and, where certification is required.
and Pressure Vessel Code,Section III,' has developed a certify the magnitude of the reaction force anticipated
('ode Case which includes requirements and guidance for from discharge of the valves. They should also stipulate the design of piping for pressure relief valve stations. the anticipated transient behavior of this force.
This Case was approved on March 3, 1973, as Case 1569, Interpretations of the ASME Boiler and Pressure Vessel 3. Experience seems to indicate that the discharge of Code. one valve in a multiple-valve installation on a single run pipe could 'lead to premature discharge of the other valves due to mechanical or hydraulic shock transmitted
' American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section III, "'Nuclear Power Plant through the common piping or due to other types of Components," hereinafter referred to as the Code. interaction. Because of this potential for simultaneous USAEC REGULATORY GUIDES Copies of published guides may be obtained by request indicating the division- desired to the U.S. Atomic Energy Commission, Washington, D.C. 20545, Regulatory Guides are issued to describe and make available to the public Attention: Director of Regulatory Standards. Comments and suggestions fot methods acceptable to the AEC Regulatory staff of implementing specific parts of improvements in these guides are encouraged and should be sent to the Secretar,.
the Commissions' regulations, to delineate techniques used by the staff in of the Commission, U.S. Atomic Energy Commission, Washington, D.C. 20545, evaluating specific problems or postulated accidents, or to provide guidance to Attention: Chief, Public Proceedings Staff.
applicants. Regulatory Guides are not substitutes for regulations and compliance with them is not reouired. Methods and solutions different from those set out in The guides are issued in the following ten broad divisions:
the guides will be acceptable if they provide a basis for the findings requisite to the iruance or continuance of a permit or license by the Commission. 1. Power Reactors
6. Products
2. Research and Test Reactors
7. TranspOrtation
3. Fuels and Materials Facilities 8. Occupational Health Published guides will be revised periodically, as appropriate, to accommodate 4. Environmental and Siting 9. Antitrust Review comments and to reflect new information or experience. 6. Materials and Plant Protection 1
0. General
discharge, a reasonable position to assure adequate Pressure Relief Valve Station," should be used in the strength is to require consideration of the most severe design and evaluation of the structural and pressure potenlial sequence of discharges; e.g., either the boundary integrity of piping subjected to the reaction simultaneous discharge of' all the relief valves on any forces associated with pressure relief valve discharges, single run pipe in a multiple-valve installation and the supplemented by the following:
restiltani combined dynamic load or, where forces may cou.lllei:act each other, a sequence of discharges such that the dynamic effects combine in that phase relation I. The magnitude of the reaction force resulting from which is estimated to induce the maximum effect at any discharge of the pressure relief valve, the anticipated po)int. Multiple discharge reaction forces which act to transient behavior of this force, and the basis for the induce forces or moments in directions opposite to each determination of the specified magnitude should be set other should not be considered to act with their forth in the Report on Overpressure Protection or Dynamic Load Factor (DLF) applied simultaneously. Analysis on Overpressure Protection and in the Owner's Design Specication, for cases where such reports are
4. The requirements of Code Case 1569 do not clearly required by the Code.'
state that the reaction forces and moments are to be included in evaluation of stresses for all components and all connecting welds of the pressure relief station and the 2. Where more than one valve is installed on the same run pipe. Also, the Code Case does not clearly state that run pipe, the sequence of valve openings to be assumed maximum instantaneous values of forces and moments in analyzing for the stress at any piping location should should be used in the calculation of both primary be that sequence which is estimated to induce the stresses and secondary stresses. The maximum maximum instantaneous value of stress at that location, instantaneous value should be determined either by unless another sequence is specified in the Design applying a Dynamic Load Factor to the steady-state Specification based on justification delineated in the forces and moments or by performing a dynamic Report on Overpressure Protection or Analysis on hvdraulic/structural system analysis, as stated in the Overpressure Protection.
Code Case. Regulatory Positions C.3. and C4. are included to clarify these requirements. A Dynamic Load Factor of 2.0 may be Used in lieu of a dynamic analysis 3. Stresses should be evaluated, and applicable stress to determine the DLF. limits as cited in Code Case 1569 should be satisfied for all components of the run pipe and connecting systems
5. Code Case 1569 indicates in Category 4 that and the pressure relief valve station including supports
,Jet:_iited reeps ar. under consideration fnr the design of and all connecting welds between these components.
piping of a pressure relief valve installation with closed discharge systems, open discharge systems with a long discharge pipe, and systems with slug flow as from a 4. In meeting the requirements of paragraph C.3.
water seal. The scope of this regulatory guide does not above, the contribution from the reaction force and the include such systems. moments resulting from that force should include the effects of the Dynamic Load Factor or should use the
C. REGULATORY POSITION
maximum instantaneous values of forces and moments for that location as determined by the dynamic For those pressure relief valve stations2 within its hydraulic/structural system analysis. This requirement scope, ASME Code Case 1569, "Design of Piping for should be satisfied in demonstrating satisfaction of all design limits at all locations of the run pipe and the
2 These requirements should also be considered for pressure relief valve station for Class 1, 2, and 3 piping.
application to blowdown valves whose discharge pipe geometry A Dynamic Load Factor (DLF) of 2.0 may be used in kneets tile requirements of Code Case 1569. lieu of a dynamic analysis to determine the DLF.
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