Regulatory Guide 1.26
| ML003739964 | |
| Person / Time | |
|---|---|
| Issue date: | 02/29/1976 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| References | |
| RG-1.06, Rev 3 | |
| Download: ML003739964 (3) | |
U.S. NUCLEAR REGULATORY COMMISSION
REGULATORY GUIDE
OFFICE OF STANDARDS DEVELOPMENT
REGULATORY GUIDE 1.26 QUALITY GROUP CLASSIFICATIONS AND STANDARDS FOR
WATER-, STEAM-, AND RADIOACTIVE-WASTE-CONTAINING
COMPONENTS OF NUCLEAR POWER PLANTS
A. INTRODUCTION
General Design Criterion 1, "Quality Standards and Records," of Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50, "Licensing of Production and Utilization Facilities," requires that structures, systems, and components important to safety be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. Section 50.55a,
"Codes and Standards," of 10 CFR Part 50 requires that components of the reactor coolant pressure boundary be designed, fabricated, erected, and tested in accordance with the requirements for Class 11 components of Section III of the ASME Boiler and Pressure Vessel or equivalent quality standard
s. This guide desc a
quality classification system related to specified na alU
standards that may be used to det r er standards acceptable to the NRC staff satisnmg General Design Criterion 1 for other )ety-r ed components containing water, steam, or tive material in light-water-cooled nuclear power plan B. DISd After reviewing r
pplications for con struction permits v ope* glicenses and after dis cussions with r"
tativ of professional societies and industr fe lO
has developed a quality classification for safety-related components con taining water, or radioactive material in water cooled nuc po r plants. The system consists of four
'Editions prior to 1971 of the ASME Boiler and Pressure Vessel Code,Section III, "Nuclear Power Plant Components," use the term Class A in lieu of Class 1.
Revision 3 February 1976 USNRC REGULATORY GUIDES
Comments should be sent to the Secretary of the Commission. U.S. Nuclear ReglaorReguletorv Commission, Washington. D.C.
05 Attention: Docketing and Regulatory Guides are issued to describe and make available to the public segulato c0
methods acceptable to the NRC staff of implementing specific parts of the ice Section.
Commission's regulations, to delineate techniques used by the staff in evalu.
The guideseare issued inthe following ten broad divisions:
eting specific problems or postulated accidents, or to provide guidance to appli cants. Regulatory Guides are not substitutes tor regulations, and compliance I. Power Reactors
6. Products with them is not required. Methods and solutions different from those set out in
2. Research and Test Reactors
7. Transportation the guides will be acceptable if they provide a basis for the findings requisite to
3. Fuels and Materials Facilities
8. Occupational Health the issuance or continuance of a permit or license by the Commission
4ý Environmental and Siting
9. Antitrust Review Comments and suggestions for improvements in these iuides are encouraged
5. Materials and Plant Protection
10 General at all times, and guides will be revised, as appropriate, to accommodate com ments and to reflect new information or experience. However. comments on Copies of published guides may be obtained by written request indicating the this guide. if received within about two months after its issuance, will be per- divisions desired to the U.S. Nuclear Regulatory Commission. Washington. D.C.
ticularly useful in evaluating the need for an early revision
20655. Attention: Director. Office of Standards Development.
quality groups, A throu me s for assigning components to these alit oups, d the specific quality standards app*
quality group. The initial portion of t sy is cribed in §50.55a of
"cre s that components of the reactor coolant e
undary be designed, fabri cated, ere an d to the highest available national st M
s corresponds to the quality stan d g
r quality Group A of the NRC
system_ .
e describes a method for determining tab onty standards for the remaining safety r
colonents containing radioactive material, a
steam, i.e., quality Group B, C, and D
Shnents. Other systems not covered by this guide, ch as instrument and service air, diesel engine and its erators and auxiliary support systems, diesel fuel, emergency and normal ventilation, fuel handling, and radioactive waste management systems,2 should be designed, fabricated, erected, and tested to quality standards commensurate with the safety function to be performed. Evaluation to establish the quality group classification of these other systems should include consideration of the guidance provided in regulatory positions C.1 and C.2 of this guide.
C. REGULATORY POSITION
1. The Group B quality standards given in Table 1 of this guide should be applied to water- and steam containing pressure vessels, heat exchangers (other than turbines and condensers), storage tanks, piping, pumps, and valves that are either part of the reactor coolant pressure boundary defined in §50.2(v) but excluded
'Specific guidance on the quality group classification of radio- I
active waste management systems is under development.
- Lines indicate substantive changes from previous issue.
from the requirements of §50.55a3 pursuant to foot note 2 of that section or not part of the reactor coolant pressure boundary but part of:
a. Systems or portions of systems4 important to safety that are designed for (1) emergency core cooling,
(2) postaccident containment heat removal, or (3) post accident fission product removal.
b. Systems or portions of systems4 important to safety that are designed for (1) reactor shutdown or
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 stop and bypass valvess and connected piping up to and including the first valve that is either normally closed or capable of automatic closure during all modes of normal reactor operation. Alternatively, for boiling water re actors containing a shutoff valve (in addition to the two containment isolation valves) in the main steam line and in the main feedwater line, Group B quality standards should be applied to those portions of the steam and feedwater systems extending from the outermost con tainmen/t isolation valves up to and including the shutoff valve or the first valve that is either normally closed or capable of automatic closure during all modes of normal reactor operation.
d. Those portions of the steam and feedwater systems of pressurized water reactors extending from and including the secondary side of steam generators up to and including the outermost containment isolation valves and connected piping up to and including the first valve (including a safety or relief valve) that is either normally closed or capable of automatic closure during all modes of normal reactor operation.
e. Systems or portions of systems 4 that are connected to the reactor coolant pressure boundary and are not capable of' being isolated from the boundary during all modes of normal reactor operation by two valves, each of which is either normally closed or capable of automatic closure.
2. The Group C quality standards given in Table 1 of this guide should be applied to water-, steam-, and
3Group A quality standards that are required for pressure containing components of the reactor coolant pressure bound ary are specified in Section 50.55a of 10 CFR Part 50.
"4The system boundary includes those portions of the system required to accomplish the specified safety function and connected piping up to and including the first valve (including a safety or relief valve) that is either normally closed or capable of aitomatic closure when the safety function is required.
$The turbine stop valve and the turbine bypass valve, although not included in quality group B, should be subjected to a quality assurance program at a level generally equivalent to quality group B.
radioactive-waste-containing pressure vessels, heat ex 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 B but part of:
a. Cooling water and auxiliary feedwater systems or portions of these systems4 important to safety that are designed for (1) emergency core cooling, (2) post accident containment heat removal, (3) postaccident containment atmosphere cleanup, or (4) residual heat removal from the reactor and from the spent fuel storage pool (including primary and secondary cooling systems).
Portions of these systems that are required for their safety functions and that (1) do not operate during any mode of normal reactor operation and (2) cannot be tested adequately should be classified as Group B.
b. Cooling water and seal water systems or por tions of these systems 4 important to safety that are designed for functioning of components and systems important to safety, such as reactor coolant pumps, diesels, and control room.
c. Systems or portions of systems 4 that are connected to the reactor coolant pressure boundary and are capable of being isolated from that boundary during all modes of normal reactor operation by two valves, each of which is either normally closed or capable of automatic closure.6 d. Systems, other than radioactive waste manage ment systems, 2 not covered by items 2.a. through 2.c.
above that contain or may contain radioactive material and whose postulated failure would result in conserva tively calculated potential offsite doses (using meteorol ogy as recommended by Regulatory Guide
1.3,
"Assumptions Used for Evaluating the Potential Radio logical Consequences of a Loss of Coolant Accident for Boiling Water Reactors," and Regulatory Guide 1.4,
"Assumptions Used for Evaluating the Potential Radio logical Consequences of a Loss of Coolant Accident for Pressurized Water Reactors") that exceed 0.5 rem to the whole body or its equivalent to any part of the body.
For those systems located in Seismic Category I struc tures, only single component failures need be assumed.
(However, no credit for automatic isolation from other components in the system or for treatment of released material should be taken unless the isolation or treat ment capability is designed to the appropriate seismic and quality group standards and can withstand loss of offsite power and a single failure of an active compo nent.)
4Components in influent lines may be classified as Group D
provided they are capable of being isolated from the reactor coolant pressure boundary by an additional valve which has high leaktight integrity.
1.26-2
3. The Group D quality standards given in Table I of this guide should be applied to water- and steam containing components not part of the reactor coolant pressure boundary or included in quality Groups B or C
but part of systems or portions of systems that contain S-or may contain radioactive material.
D. IMPLEMENTATION
The purpose of this section is to provide information to applicants regarding the NRC staff's plans for using this regulatory guide.
This guide reflects current NRC staff practice. There fore, except in those cases in which the applicant proposes an acceptable alternative method for comply ing with specified portions of the Commission's regula tions, the method described herein is being and will continue to be used in the evaluation of submittals for operating license or construction permit applications until this guide is revised as a result of suggestions from the public or additional staff review.
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 III,
Vessel Code,Section III,
Vessel Code,Section VIII,
"Nuclear Power Plant Com-
"Nuclear Power Plant Corn- Division 1 ponents," a, b, c Class 2 ponents,,a, b, c Class 3 Piping As above As above ANSI B31.1.0 Power Piping Pumps As above As above Manufacturers standards Valves As above As above ANSI B31.1.0
Atmospheric As above As above API-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 appropriate. 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.