Regulatory Guide 1.26: Difference between revisions

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{{Adams
{{Adams
| number = ML003739964
| number = ML21319A023
| issue date = 02/29/1976
| issue date = 11/16/2021
| title = For Comment, Quality Group Classifications & Standards for Water-,Steam & Radioactive-Waste-Containing Components of Nuclear Power Plants
| title = Quality Group Classifications and Standards for Water-, Steam-, and Radioactive-Waste-Containing Components of Nuclear Power Plants
| author name =  
| author name =  
| author affiliation = NRC/RES
| author affiliation = NRC/ACRS
| addressee name =  
| addressee name =  
| addressee affiliation =  
| addressee affiliation =  
| docket =  
| docket =  
| license number =  
| license number =  
| contact person =  
| contact person = Jim Steckel
| document report number = RG-1.06, Rev 3
| case reference number = RG-1.026, Rev 6
| document type = Regulatory Guide
| document type = Meeting Briefing Package/Handouts, Slides and Viewgraphs
| page count = 3
| page count = 13
}}
}}
{{#Wiki_filter:U.S. NUCLEAR REGULATORY COMMISSION
{{#Wiki_filter:NRC Regulatory Guide 1.26, Revision 6 NRC Staff ACRS Presentation November 16, 2021 Quality Group Classifications and Standards for Water-, Steam-, and Radioactive-Waste- Containing Components of Nuclear Power Plants
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==
NRC Staff Team Members for RG 1.26 Revision
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
James Steckel, RGPMB/DE/RES
*
Ian Tseng, Acting Branch Chief, EMIB/DEX/NRR
*
Thomas Scarbrough, EMIB/DEX/NRR
*
Edward Stutzcage, DRCB/DRA/NRR
*
Timothy Lupold, UTB1/DANU/NRR
*
Nicholas Hansing, MSB/DFM/NMSS
*
Tuan Le, UNPO/DANU/NRR
2


====s. This guide desc a ====
Reason for Revision
quality classification system related to specified na alU
* Revision 5 to RG 1.26 was an administrative update
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
* Proposed Revision 5 presented to ACRS in October 2016
pplications for con struction permits v ope* glicenses and after dis cussions with r"
* ACRS letter dated 10-17-2016 stated:
tativ of professional societies and industr fe lO
- Revision 5 to RG 1.26 should be issued
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
- Next revision to RG 1.26 should be broadened to include basic principles for assignment of components to each quality group
'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.
* EDO responded on 12-13-2016 that Revision 5 to RG 1.26 would be issued, and next revision to RG 1.26 would address ACRS recommendations
* NRC issued proposed Revision 6 to RG 1.26 (DG-1371)
for public comment in April 2021
3


Revision 3 February 1976 USNRC REGULATORY GUIDES
Key Changes
Comments should be sent to the Secretary of the Commission. U.S. Nuclear ReglaorReguletorv Commission, Washington. D.C.
* New Appendix A, Alternative Classification for Components in Light-Water-Cooled Nuclear Power Plants, discusses component classification method described in American National Standards Institute (ANSI)/American Nuclear Society (ANS) Standard 58.14-
2011, Safety and Pressure Integrity Classification Criteria for Light Water Reactors.


05 Attention: Docketing and Regulatory Guides are issued to describe and make available to the public segulato c0
* Updated NRC staff position on classification of Quality Group C components to reflect latest guidance on systems that contain radioactive material.
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.
* NRC staff improved proposed Revision 6 to RG 1.26 in response to public comments.


The guideseare issued inthe following ten broad divisions:
4
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
Appendix A to Revision 6 to RG 1.26
20655. Attention: Director. Office of Standards Development.
* Applicant or licensee may propose use of the classification method in ANSI/ANS-58.14-2011 subject to considerations discussed in RG 1.26, Appendix A
* ANSI/ANS-58.14 scope is broader than RG 1.26 to apply to pressure integrity for water, steam, or radioactive material components
* ANSI/ANS-58.14 does not include radiological criteria in RG 1.26 to complement application of ANSI/ANS-58.14 with RG 1.26
* Based on terminology differences, ANSI/ANS-58.14 users should consider full scope of 10 CFR Part 50, Appendix A
5


quality groups, A throu me s for assigning components to these alit oups, d the specific quality standards app*
Appendix A to Revision 6 to RG 1.26 (continued)
quality group. The initial portion of t sy is cribed in §50.55a of
* Specific guidance provided for ANSI/ANS-58.14 users in developing Class 1 to 4 (Quality Group A to D)
10 CFR Part 50.
* User should apply applicable ASME Boiler and Pressure Vessel Code, Section III, Subsection NF, for snubbers
* ANSI/ANS-58.14 users should review plant-specific design in comparison to RG 1.26 because specific RG 1.26 topics (such as spent fuel pool) not addressed in ANSI/ANS-58.14
* Users should ensure that containment penetration regulations are met
* Applicable users may include 10 CFR 50.69 (risk-informed categorization and treatment) as part of classification
6


"cre s that components of the reactor coolant e
Quality Group C
undary be designed, fabri cated, ere an d to the highest available national st M
Modification in RG 1.26
s corresponds to the quality stan d g
*
r quality Group A of the NRC
Systems, other than radioactive waste management systems, not covered by Regulatory Positions 2.a through 2.c that contain or may contain radioactive material and whose postulated failure would result in conservatively calculated potential offsite doses that exceed 0.1 rem total effective dose equivalent; only single component failures need be assumed for those systems located in Seismic Category I structures, and no credit should be taken for automatic isolation from other components in the system or for treatment of released material, unless the isolation or treatment 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 component.
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==
7
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.
Response to Public Comments
* Comment:  Include 10 CFR 50.54 and 10 CFR 50.55 in list of regulatory requirements.


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:  
- Response:  Complete
a. Systems or portions of systems4 important to safety that are designed for (1) emergency core cooling,
* Comment:  Clarify applicability of ANSI/ANS-58.14 and 10 CFR 50.69
(2) postaccident containment heat removal, or (3) post accident fission product removal.
- Response: Added detailed footnote to Table 1 in RG 1.26 discussing 10 CFR 50.69
8


b. Systems or portions of systems4 important to safety that are designed for (1) reactor shutdown or
Response to Public Comments (continued)
(2) residual heat removal.
* Comment:  Add technical basis for including important to safety items in Quality Group C or delete
- Response:  Explained ANSI/ANS-58.14 provides consensus recommendation for Class 3 components (Quality Group C) and that applicants/licensees may propose a different classification method for those components
* Comment:  Term important to safety is ambiguous
- Response:  NRC staff does not consider a safety need to develop a specific definition of important to safety at this time
9


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.
NRC Response to Public Comments (continued)
* Comment:  Explain change to threshold for classification of systems containing radioactive material as Quality Group C
- Response:  RG 1.26 updated to clarify reason for change to threshold for classification of systems containing radioactive material
* Comment:  Appendix A to RG 1.26 contains information that should be included in RG 1.201
- Response:  RG 1.26, Appendix A, revised to clarify reference to RG 1.201 with consideration of future improvements to RG 1.201
* Comment:  Specific editorial suggestions
- Response:  Complete
10


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.
High Temperature Reactor Quality Group Classification
* Proposed Revision 2 to RG 1.87, Acceptability of ASME
Code, Section III, Division 5, High Temperature Reactors, (DG-1380) issued for public comment in August 2021.


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.
* Appendix A, High Temperature Reactor Quality Group Classification, in DG-1380 establishes quality group assignments for mechanical systems and components for non-light-water reactors.


2. The Group C quality standards given in Table 1 of this guide should be applied to water-, steam-, and
* DG-1380 discussed with ACRS on July 20, 2021.
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.
* RG 1.26 relies on DG-1380 for high-temperature reactor quality group classification.


$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.
11


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:
Next Steps
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).
* NRC staff has distributed proposed Revision 6 to RG 1.26 for NRC management review
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.
* NRC staff will address NRC management and ACRS recommendations when finalizing Revision 6 to RG 1.26
* NRC plans to issue Revision 6 to RG 1.26 by early
2022
12


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.
QUESTIONS?
 
13}}
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.}}


{{RG-Nav}}
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Latest revision as of 03:51, 7 February 2025

Quality Group Classifications and Standards for Water-, Steam-, and Radioactive-Waste-Containing Components of Nuclear Power Plants
ML21319A023
Person / Time
Issue date: 11/16/2021
From:
Advisory Committee on Reactor Safeguards
To:
Jim Steckel
References
RG-1.026, Rev 6
Download: ML21319A023 (13)
v • d • e


NRC Regulatory Guide 1.26, Revision 6 NRC Staff ACRS Presentation November 16, 2021 Quality Group Classifications and Standards for Water-, Steam-, and Radioactive-Waste- Containing Components of Nuclear Power Plants

NRC Staff Team Members for RG 1.26 Revision

James Steckel, RGPMB/DE/RES

Ian Tseng, Acting Branch Chief, EMIB/DEX/NRR

Thomas Scarbrough, EMIB/DEX/NRR

Edward Stutzcage, DRCB/DRA/NRR

Timothy Lupold, UTB1/DANU/NRR

Nicholas Hansing, MSB/DFM/NMSS

Tuan Le, UNPO/DANU/NRR

2

Reason for Revision

  • Revision 5 to RG 1.26 was an administrative update
  • Proposed Revision 5 presented to ACRS in October 2016
  • ACRS letter dated 10-17-2016 stated:

- Revision 5 to RG 1.26 should be issued

- Next revision to RG 1.26 should be broadened to include basic principles for assignment of components to each quality group

  • EDO responded on 12-13-2016 that Revision 5 to RG 1.26 would be issued, and next revision to RG 1.26 would address ACRS recommendations
  • NRC issued proposed Revision 6 to RG 1.26 (DG-1371)

for public comment in April 2021

3

Key Changes

  • New Appendix A, Alternative Classification for Components in Light-Water-Cooled Nuclear Power Plants, discusses component classification method described in American National Standards Institute (ANSI)/American Nuclear Society (ANS) Standard 58.14-

2011, Safety and Pressure Integrity Classification Criteria for Light Water Reactors.

  • Updated NRC staff position on classification of Quality Group C components to reflect latest guidance on systems that contain radioactive material.
  • NRC staff improved proposed Revision 6 to RG 1.26 in response to public comments.

4

Appendix A to Revision 6 to RG 1.26

  • Applicant or licensee may propose use of the classification method in ANSI/ANS-58.14-2011 subject to considerations discussed in RG 1.26, Appendix A
  • ANSI/ANS-58.14 scope is broader than RG 1.26 to apply to pressure integrity for water, steam, or radioactive material components

5

Appendix A to Revision 6 to RG 1.26 (continued)

  • Specific guidance provided for ANSI/ANS-58.14 users in developing Class 1 to 4 (Quality Group A to D)
  • Users should ensure that containment penetration regulations are met
  • Applicable users may include 10 CFR 50.69 (risk-informed categorization and treatment) as part of classification

6

Quality Group C

Modification in RG 1.26

Systems, other than radioactive waste management systems, not covered by Regulatory Positions 2.a through 2.c that contain or may contain radioactive material and whose postulated failure would result in conservatively calculated potential offsite doses that exceed 0.1 rem total effective dose equivalent; only single component failures need be assumed for those systems located in Seismic Category I structures, and no credit should be taken for automatic isolation from other components in the system or for treatment of released material, unless the isolation or treatment 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 component.

7

Response to Public Comments

- Response: Complete

- Response: Added detailed footnote to Table 1 in RG 1.26 discussing 10 CFR 50.69

8

Response to Public Comments (continued)

  • Comment: Add technical basis for including important to safety items in Quality Group C or delete

- Response: Explained ANSI/ANS-58.14 provides consensus recommendation for Class 3 components (Quality Group C) and that applicants/licensees may propose a different classification method for those components

  • Comment: Term important to safety is ambiguous

- Response: NRC staff does not consider a safety need to develop a specific definition of important to safety at this time

9

NRC Response to Public Comments (continued)

  • Comment: Explain change to threshold for classification of systems containing radioactive material as Quality Group C

- Response: RG 1.26 updated to clarify reason for change to threshold for classification of systems containing radioactive material

  • Comment: Appendix A to RG 1.26 contains information that should be included in RG 1.201

- Response: RG 1.26, Appendix A, revised to clarify reference to RG 1.201 with consideration of future improvements to RG 1.201

  • Comment: Specific editorial suggestions

- Response: Complete

10

High Temperature Reactor Quality Group Classification

Code,Section III, Division 5, High Temperature Reactors, (DG-1380) issued for public comment in August 2021.

  • Appendix A, High Temperature Reactor Quality Group Classification, in DG-1380 establishes quality group assignments for mechanical systems and components for non-light-water reactors.
  • DG-1380 discussed with ACRS on July 20, 2021.
  • RG 1.26 relies on DG-1380 for high-temperature reactor quality group classification.

11

Next Steps

  • NRC staff has distributed proposed Revision 6 to RG 1.26 for NRC management review
  • NRC staff will address NRC management and ACRS recommendations when finalizing Revision 6 to RG 1.26
  • NRC plans to issue Revision 6 to RG 1.26 by early

2022

12

QUESTIONS?

13


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