Regulatory Guide 1.26

Quality Group Classifications and Standards for Water-, Steam-, and Radioactive-Waste-Containing Components of Nuclear Power Plants

ML13038A086
Person / Time
Issue date:	09/30/1974
From:	US Atomic Energy Commission (AEC)
To:
References
RG-1.026, Rev. 1
Download: ML13038A086 (3)

iVgGY C0 Revision 1

• . U.S. ATOMIC ENERGY COMMISSION September 1974 REGULATORY GUIDE

qrrs "i DIRECTORATE OF REGULATORY STANDARDS

REGULATORY GUIDE 1.26 QUALITY GROUP CLASSIFICATIONS AND STANDARDS FOR WATER-, STEAM-, AND

RADIOACTIVE-WASTE-CONTAIN ING COMPONENTS OF NUCLEAR POWER PLANTS

A. INTRODUCTION

for assigning components to these quality groups, and the specific quality standards applicable to each quality General Design Criterion 1, "Quality Standards and group. The initial, portion of this system is described in Records," of Appendix A, "General Design Criteria for §50.55a of 10 CFR Part 50, which requires that Nuclear Power Plants," to 10 CFR Part 50, "Licensing components of the reactor coolant pressure boundyry be of Production and Utilization Facilities," requires that designed, fabricated, erected, and tested to the highest structures, systems, and components important to safety available national standards; this corresponds to the be designed, fabricated, erected, and tested to quality quality standard required for quality Group A of the standards commensurate with the importance of the AEC system. This guide describes a method for deter- safety functions to be performed. Section 50.55a, mining acceptable quality standards for the remaining

"Codes and Standards," of 10 CFR Part 50 requires that safety-related components containing radioactive components of the reactor coolant pressure boundary be material, water, or steam, i.e., quality Group B, C, and D

designed, fabricated, erected, and tested in accordance components. Other systems not covered by this guide, with the requirements for Class 1 components of such as instrument and service air, diesel engine and itsSection III of the ASME Boiler and Pressure Vessel Code generators and auxiliary support systems, diesel fuel, or equivalent quality standards. This guide describes a emergency and normal ventilation, fuel handling, and quality classification system related to specified national fire protection systems using other than water, should be standards that may be used to determine quality designed, fabricated, erected, and tested to quality standards acceptable to the Regulatory staff for satis- standards commensurate with the safety function to be fying General Design Criterion I for other safety-related performed.

components containing 'radioactive material, water, or steam in water-cooled nuclear power plants.

B. DISCUSSION

I. The group B quality standards given in Table I of this After reviewing a number of applications for con- guide should be applied to water- and steam-containing struction permits and operating licenses and after dis- pressure vessels, heat exchangers (other than turbines cussions with representatives of professional societies and condensers), storage tanks, piping, pumps, and and industry, the AEC Regulatory staff has developed a valves that are either part of the reactor coolant pressure quality classification system for safety-related com- boundary defined in §50.2(v) but excluded from the ponents containing radioactive material, water, or steam requirements of §50.55a 2 pursuant to footnote 2 of in water-cooled nuclear power plants. The system that section or not part of the reactor coolant pressure boundary but part of:

consists of four quality groups, A through D, methods

2 Editions prior to 1971 of the ASME Boiler and Pressure Vessel Group A quality standards that are required for pressure- Code,Section III, "Nuclear Power Plant Components," use the containing components of the reactor coolant pressure bound- term Class A in lieu of Class 1. ary are specified in Section 50.55a of 10 CFR Part 50.

USAEC REGULATORY GUIDES Copies of published guides may be obtained by request indicating the divisions desired to the US. 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 for methods acceptable to the AEC Regulatory staff of implementing specific parts of improvements in these guides are encouraged and should be sent to the Secretary the Commission's regulations, to delineate techniques .~ed 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: Docketing and Service Section Sapplicants. Regulatory Guides are not substitutes for regulations and compliance with them is not required. 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 issuance 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. 5. Materials and Plant Protection 1

0. General

a. Systems or portions of systems3 important to designed for (1) emergency core cooling, (2) post- safety that are designed for (1) emergency core cooling, accident containment heat removal, (3) postaccident

`.2) postaccident containment heat removal, or (3) post-

cident fission product removal.

containment atmosphere cle,.up, or (4) residual heat removal from the reactor and from the spent fuel storage pool (including primary and secondary cooling systems).

@4 b. Systems or portions of systems 3 important to Portions of these systems that are required for their safety that are designed for (1) reactor shutdown or safety functions and that either do not operate during

(2) residual heat removal. any mode of normal reactor operation or cannot be tested adequately should be classified as Group B.

c. Those portions of the steam systems of boiling water reactors extending from the outermost contain- ment isolation valve up to but not including the turbine b. Cooling water and seal water, systems or portions stop valves and connected piping up to and including the of these systems3 important to safety that are designed first valve that is either normally closed or capable of for functioning of components and systems important to automatic closure during all modes of normal reactor safety, such as reactor coolant pumps, diesels, and operation. Alternatively, for boiling water reactors con- control room.

taining a shutoff valve (in addition to the two contain- ment isolation valves) in the main steam line and in the c. Systems or portions of systems 3 that are connected main feedwater line, Group B quality standards should to the reactor coolant pressure boundary and are capable be applied to those portions of the steam and feedwater of being isolated from that boundary during all modes of systems extending from the outermost containment normal reactor operation by two valves, each of which is isolation valves up to and including the first valve that is either normally closed or capable of automatic closure. 4 either normally closed or capable of automatic closure during all modes of normal reactor operation.

d. Radioactive waste treatment, handling, and dis- d. Those portions of the steam and feedwater sys- posal systems, except those portions of these systems tems of pressurized water reactors extending from and whose postulated failure would not result in conserva- including the secondary side of steam generators up to tively calculated potential offsite doses that exceed 0.5 and including the outermost containmenrt isolation rem to the whole body or its equivalent to any part of the body. For those systems located in Seismic Category

4 valves and connected piping up to and including the first valve (including a safety or relief valve) that is either I structures, only single component failures need be yormally closed or capable of automatic closure during assumed. (However, no credit for automatic isolation

\ ,*dlmodes of normal reactor operation. from other components in the system or for treatment of released material should be taken unless the isolation e. Systems or portions of systems 3 that are connected or treatment capability is designed to the appropriate to the reactor coolant pressure boundary and are not seismic and quality group standards and can withstand capable of being isolated from the boundary during all loss of offsite power and a single failure of an active modes of normal reactor operation by two valves, each component.) Parts of these systems beyond the pro- of which is either normally closed or capable of cessing steps (such as monitoring tanks) may be classi- automatic closure. fied as Group D if the plant Technical Specifications limit inventories to levels which, if released, would not

2. The group C quality standards given in Table 1 of this result in conservatively calculated potential offsite doses guide should be applied to water-, steam-, and that exceed 0.5 rem to the whole body or its equivalent radioactive-waste-containing pressure vessels, heat ex- to any part of the body.

changers (other than turbines and condensers), storage tanks, piping, pumps, and valves not part of the reactor coolant pressure boundary or included in quality Group e. Other systems, not covered by items 2.a. through B but part of: 2.d. above, that contain or may contain radioactive material and whose postulated failure would result in a. Cooling water and auxiliary feedwater systems or conservatively, calculated potential offsite doses that portions of these systems 3 important to safety that are exceed 0.5 rem to the whole body or its equivalent to any part of the body. For those systems located in

'The system boundary includes those portions of the system Seismic Category I structures, only single component required to accomplish the specified safety function and failures need be assumed. (However, no credit for connected piping up to and including the first valve (including a automatic isolation from other components in the safety or relief valve) that is either normally closed or capable system or for treatment of released material should be

.of automatic closure when the safety function is required.

taken unless the isolation or treatment capability is

'Components in influent lines may be classified as Group D

provided they are capable of being isolated from the reactor designed to the appropriate seismic and quality group coolant pressure boundary by an additional valve which has standards and can withstand loss of offsite power and a high leak-tight integrity. single failure of an active component,)

.1.26-2

3. The Group D quality standards given in Table 1 of systems and components of all plants for which the this guide should be applied to water- and steam- docket date of the application for construction permit is containing components not part of the reactor coolant subsequent to January 1, 1975.

pressure boundary or included in quality Groups B or C

but part of systems or portions of systems that contain 2. The quality group ,classifications and standards or may contain radioactive material. described in Section C of this guide may be applied, at the designer's option, to systems and components of plants for which the docket date of the application is

D. IMPLEMENTATION

prior to January 1, 1975.

The purpose of this section is to provide guidance to 3. Other methods for determining acceptable quality applicants regarding implementation of the quality standards for systems and components not in quality group classifications and standards described in Section Group A may be proposed to the Commission by C of this guide. applicants and may be determined to be acceptable if they provide a comparable level of safety.

1. The quality group classifications and standards described in Section C of this guide for quality Groups sAcceptable standards for quality Group A components are B, C, and D' should be applied to the appropriate described in §50.55a of 10 CFR Part 50.

TABLE 1 QUALITY STANDARDS

Components Quality B Quality C Quality D

Pressure Vessels ASME Boiler and Pressure ASME Boiler and Pressure ASME Boiler and Pressure Vessel Code,Section II I, Vessel CodeSection II I, Vessel Code,Section VIII

"Nuclear Power Plant Com- "Nuclear Power Plant Coin- Division 1 ponents," a, b, c Class 2 ponents," a, b, c Class 3 Piping As above As above ANSI B 31.1.0 Power Piping I

Pumps As above As above Manufacturers standards Valves As above As above ANSI B31.1.0

Atmospheric As above As above AP1-650, AWWA D 100, or Storage Tanks ANSI B 96.1

0-15 psig As above As above API-620

Storage Tanks aSee Section 50.55a for guidance with regard to the Code and Addenda to be applied.

bASME Code N- symbol need not be applied.

CThe specific applicability of code cases will be covered separately in other regulatory guides or in Commission regulations, where appro- priate. Applicants proposing the use of code cases not covered by guides or regulations should demonstrate that an acceptable level of quality and safety would be achieved.

1.26-3