ML19208C483
| ML19208C483 | |
| Person / Time | |
|---|---|
| Issue date: | 08/31/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-75-087, NUREG-75-087-09.3.1, NUREG-75-87, NUREG-75-87-9.3.1, PSRP-9.3.1-R1, SRP-09.03.01-FC, SRP-9.03.01-FC, NUDOCS 7909260492 | |
| Download: ML19208C483 (8) | |
Text
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U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulat'on PROPOSED REVISION 1 STANDARD REVIEW PLAN (NUREG 75/087)
SECTION 9.3.1 COAPRESSED AIR SYSTEM REVIEW RESPONSIBILITIES
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Prima ry - Auxiliary Systems Branch (ASB) i Secondary - Structural Engineering Branch (SEB)
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Mechanical Engineering Branch (MEB)
Instrumentation and Control Systems Branch (ICSB) l Power Systems Branch (PSB) 1.
AREAS OF REVIEW The compressed air system (CAS) provides air to safety related equipment and also to plant equipment used only for normal facility operation. ASB reviews the entire compressed air system since there may be cases
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where two systems or subsystems are provided, i.e., a safety-related control air system (SRCAS) and a station service system for non-safety-related equipment. If the two systems'are interconnected, the area of review will extend f rom the safety-related portion to the outermost isolation valve on all interconnections between the two systems. If the systems are not connected, the review will be limited to the SRCAS. The ASB reviews the SRCAS to ensure conformance with the requirements of General Design Criteria 2, 4, and 5.
1.
ASB reviews the systems to identify the safety-related air-operated devices that are supplied by the system and whether each requires a source of supply air in order to perform the safety related function.
2.
ASB then reviews to determine that:
A failure of a component or the loss of a' compressed air source does not negate functioning of a a.
safety-related system.
b.
The system components and pipes have sufficient physical separation or barriers to protect the essential portions of'the system frem missiles and from the ef fects of breaks and cracks in high-and moderate-energy fluid system piping close to the SRCAS.
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3.
The ASB reviews the system to determine that the effects of failure of non-seismic Category I equipment I;
or components will not affect the functioning of the SRCAS.
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Lines indicate substantive ~ changes from original version.
This proposed revision to the Standard Review Plan and the supporting value/ impact statement have not
[i received a complete staff review and approval and do not represent an official NRC staff position. Public comments are being solicited on both the revision and the value/ impact statement (including any implementa-tion schedule) prior to a review by the Regulatory Requirements Review Committee and their recommendation as to whether this revision should be approved. Comments should be sent to the Secretary of the Commission, U.S. Nuclear Regulatory Commission, Washington, D.C. 20555, Attention: Docketing and Service Branch. All comments received by OCT 24 M7Q will be consldered by the Committee. A summary of the meeting of the c
Committee at which this revision is considered, the Committee recommendations, and all of the associated documents and comments considered by the Committee will be made publicly available prior to a decision by the Director, Of fice of Nuclear Reactor Regulation, on whether to implement this revision.
Proposed Revision 1 Draft 1 August 1979 98 m 2 7 90 9 '28MR
4.
ASB reviews the design of the SRCAS with respect to the following:
a.
Capability to isolate portions or components of the system in case of component malfunction.
b.
Instrumentation and control features provided to determine and verify that the system is operating in a correct mode (e.g., valve position indication, pressure).
c.
Capability of the system to function in the event of adverse environmental phenomena, abnormal operational requirements, or accident conditions such as a loss-of-coolant accident (LOCA) or main steam line break concurrent with loss of offsite power.
l d.
Capability of the system to supply clean, dry, oil-free instrument air.
5.
The applicant's proposed technical specifications are reviewed for operating license applications as they relate to areas covered in this SRP section.
Secondary reviews are performed by other branches and the
.elts are used by the ASB to complete the over-all review of the system. The SEB will determine the acceptability of the design analyses, procedures, and criteria used to establish the ability of seismic Category I structures housing the system and sunporting systems to withstand the ef fects of natural phenomena such as the safe shutdown earthquake (SSE), the probable maximum flood (PMF), and tornado missiles. The MEB will review the seismic qualification of compo-nents and confirm that the system is designed in accordance with applicable codes and standards. The ICSB and PSB will determine the adequacy of the desigr., installation, inspection, and testing of all essential electrical components, system controls, and instrume.tation.
II.
ACCEPTANCE CRITERIA Acceptability of the design of the safety-related control air system, as described in the applicant's Safety Analysis Report (SAR), is based on specific general design criteria and regulatory guides. The design of the SRCAS is acceptable if the integrated design of the system is in accordance with the following:
1.
General Design Criterion 2, as related to the system being capable of withstanding the ef fects of natural phenomena such as earthquakes, tornadoes, hurricanes, and floods.
2.
General Design Criterion 4, with respect to the system being capable of withstanding the effects of external missiles and internally generated missiles, pipe whip, and jet impingement forces associated with pipe breaks.
3.
General Design Criterion 5, as related to the capability of shared systems and components important to safety to perform required safety functions.
4.
Regulatory Guide 1.26, as related to the quality group c.lassification of systems and components.
5.
Regulatory Guide 1.29, as related to the seismic design classification of system components.
l 6.
Regulatory Guide 1.102, as related to the protection of structures, systems, and components important to' safety from the effects of flooding.
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Regulatory Guide 1.117, as related to the protection of structures, systems, and components important to safety from the effects of tornado missiles.
8.
Branch Technical Position ASB 3-1, as related to breaks in high-energy piping or cracks in mooerate-energy piping systems outside containment.
9 ANSI MC 11.1-1976, (ISA-57.3) as related to minimum instrument air quality standards.
For those areas of review identified in subsection I of this SRP section as being the responsibility of other branches, the acceptance criteria and their methods of application are containad in the SRP sections corresponding to those branches.
III. REVIEW PROCEDURES The procedures below are used during the construction permit (CP) review to determine that the design criteria and bases and the preliminary design as set forth in the preliminary safety analysis report meet the recommendations and requirements given in subsection II.
For operating license (OL) reviews, the proce-dures are used to verify that the initial design criteria and bases have been appropriately implemented in the final design as set forth in the final safety analysis report. The procedures for OL reviews include a determination that the content and intent of the technical specifications prepared by the applicant are in agreement with the requirements for system testing, minimum performance, and surveillance developed as a result of the staff's review.
Upon request from the primary reviewer, the secondary review branches will provide input for the areas of review stated in subsection I.
The primary reviewer obtains and uses such input as required to ensure that this review procedure is complete.
As a result of various CAS designs provided for different plants, there will be variations in system require-ments. For the purpose of this plan, a typical system is assumed that has two inoependent systems, the plant service air system and a safety-related control air system (SRCAS). For cases where there are variations f rom this arrangement, the reviewer adjusts the review procedures given below. However, the system design would be required to meet the recommendations and requirements in subsection II.
The reviewer will select and emphasize material from this plan as appropriate for a particular case.
1.
The SAR is reviewed to identify from information in the system description section and the piping and instrumentation diagrams (P&lDs) the SRCAS equipment used for normal operation and for safety feature operation. The reviewer determines that the systems affected by the loss of of f site power and subsequent loss of air supply will fail in a safe position.
2.
The system P& ids, layout drawings, and component descriptions and characteristics are reviewed to deter-mine the following:
a.
Essential portions of the SRCAS are correctly identified and are isolable free the nonessential portions of the system. The P& ids are reviewed to verify that they clearly indicate the physical division between each portion. System drawings are also reviewed to verify that they show the means for accomplishing isolation and the system description is reviewed to identify minimum performance requirements of the isolation valves.
'or the typical system, the drawings and 9.3.1-3
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descriptions are reviewed to verify that two automatically operated isolation valves in series separate the nonessential from the essential portions and components.
b.
Essential portions of the SRCAS, including the isolation valves separating essential from non-essential portions, are classified Quality Group C ano seismic Category I.
Component and system descriptions in the SAR that identify mechanical and performance characteristics are reviewed to verify that the above classifications have been included, and that the P&lD's indicate points of t
change in any design classification.
i The SRCAS consists of non oil lubricated (dry) compressors and automatic molecular sieve air dryers I
c.
with input and output filters.
3.
The reviewer verifies that the system has been designed so that system function will be maintained, as required, in the event of adverse environmental phenomena, certain pipe breaks, or a loss of of f site r
power.
The reviewer evaluates the system using engineering judgment and the results of failure modes f
and effects analyses to determine that:
i The failure of nonessential portions of the system or of other systems not designed to seismic Cate-l a.
gory I standards and loc ated close to essential portions of the SRCAS, or of non-seismic Category I structures that house, support, or are close to the SRCAS, will not preclude operation of the l
essential portions of the SRCAS. Statements in the SAR to the effect that the above conditions are met are acceptable.
b.
The essential portions of the SRCAS are protected from the effects of floods, hurricanes, tornadoes, C_
l and internally or externally generated missiles. The location and the design of the system, struc-tures, or cubicles are reviewed to determine that the degree of protection is adequate. A state-ment to the effect that the system is located in a seismic Category I structure that is tornado missile and flood protected, or that components of the system will be located in individual cubicles or rooms that will withstand the effects of tornado winds, flooding, and missiles is acceptable.
An adequate SRCAS air supply source is available, conside.-ing the loss of of fsite power.
If the c.
minimum performance requirements stated in the SAR are met, the system design will be acceptable l
assuming a concurrent failure of a single active component, including an emergency power source.
Statements in the SAR and the results of failure modes and effects analyses are considered to ensure that the system meets these requirements. These will be acceptable verification of system functional reliability.
i d.
The essential components of the system are protected from the effects of high-and moderate energy line breaks.
Layout drawings are reviewed to ensure that no high-or moderate energy piping systems are close to essential portions of the SRCAS or that protection from the effects of failure will be providef. The means of providing such protection will be given in Section 3.6 of the SAR, and procedures for reviewing the information are given in the corresponding SRP sections.
l I
4 The descriptive information, P& ids, SRCAS drawings, and f ailure modes and ef fects analyses in the SAR are reviewed to ensure that the SRCAS portion of the compressed air system will function following design l
basis accidents assuming a concurrent single active failure. The reviewer evaluates the information 9.3.1-4 I
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presented in the SAR to determine the ability of required components to function, traces the availabil-ity of these components on system drawings, and checks that the SAR contains verification that minimum compressed air flow requirements are met for each degraded situation for the required time spans. For each case the design will be acceptable if minimum system requirements are met.
5.
The reviewer verifies that an adequate maintenance and periodic testing program is planned to ensure l
continuous reliable functioning of SRCAS.
IV.
EVALUATION FINDINGS The reviewer veriffes that sufficient information has been provided and that his review supports conclusions of the following type, to be included 'n the staff's safety evaluation report:
"The compressed air system inclejes all components and piping and the points of connection or inter-faces with other systems. The essential portions of the compressed air system and the safety related control air system required for maintaining a continuous air supply to safety related components con-forms to the following regulations and guidelines: (a) General Design Criterion 2 " Design Bases for Protection Against Natural Phenomena " (b) General Design Criterion 4. " Environmental and Misslie Design Bases," (c) General Design Criterion 5, " Sharing of Structures, Systems, and Components," (d) Regulatory Guide 1.26, " Quality Group Classification and Standards for Water, Steam, and Radioactive-Waste-Containing Components of Nuclear Power Plants," (e) Regulatory Guide 1.29, " Seismic Design Classification,"
(f) Regulatory Guide 1.102, " Flood Protection for Nuclear Power Plants," (g) Regulatory Guide 1.117,
" Tornado Design Classification," (h) Branch Technical Position ASB 3-1, " Protection Against Postulated Piping Failures in fluid Systems Outside Containment."
"The staff concludes that the design of the compressed air system conforms to all applicable regula-tions, guides, staff positions, and industry standards and is therefore acceptable."
REFERENCES 1.
General Design Criterion 2, " Design Bases for Protection Against Natural Phenomena," of Appendix A to 10 CFR Part 50.
2.
General Design Criterion 4, " Environmental and Missile Design Bases," of Appendix A to 10 CFR Part 50.
3.
General Design Criterion 5, " Sharing of Structures, Systems, and Components," of Appendix A to 10 CFR Part 50.
4.
Regulatory Guld:r 1.26, " Quality Group Classifications and Standards for Water, Steam-and Radioactive-Waste-Containing Components of Nuclear Power Plants."
5.
Regulatory Guide 1.29 " Seismic Design Classification."
6.
Regulatory Guide 1.102, " Flood Prctection for Nuclear Power Plants."
7.
Regulatory Guide 1.117, " Tornado Design Classification."
8.
Branch Technical Positions ASB 3-1, " Protection Against Postulated Piping Failures in Fluid Systems Outside Containment," attached to SRP Section 3.6.1, and MEB 3-1, " Postulated Break and Leakage Loca-tions in fluid System Piping Outside Containment," attached to SRP Section 3.6.2.
9.
ANSI MC 11.1-1976 (ISA-57.3), " Quality Standard for Instrument Air "
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a U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Value-Impact Analysis Proposed Revision 1 Draft 1 STANDARD REVIEW PLAN SECTION 9.3.1 1.
THE PROPOSED ACTION Standard Review Plan (SRP) Section 9.3.1, " Compressed Air System," establishes the requirement for those compressed air systems (e.g., instrument air systems) that provide air to safety-related equipment. Because of the importance of ensuring the operability of safety-related valve actuators and instrumentation, and because of the potential for long-term degradation of these components due to contaminated or dirty supplies, this proposal incorporates minimum air quality standards set forth in ANSI MC 11.1-1976 (ISA-57. 3), " Quality Standard for instrument Air," into SRP Section 9.3.1.
2.
BACKGROUND Present review of the instrument air system does not consider the system or portions of the system unless the system performs a safety-related function. Those instrument air systems or portions thereof that are safety-related and are essential to ensuring a safe plant shutdown, should contain air of the highest quality achievable with current industry practice.
Contaminated or dirty compressed air can result in erratic operation of valve actuators and instrumentation.
Oil and moisture are particularly harmful in that they can cause clogging and corrosion of air operated components.
Past operating experience has shown this to be a problem in some plants.
The following instrument air quality standards are coatained in ANSI MC 11.1-1976 (ISA-57.3), and are con-sidered applicable for safety-related instrument air requirements in nuclear power plants:
1.
Dew point (at line pressure) - at least 10*C (18'F) below the minimum local recorded ambient temper-ature at the plant site.
2.
Particle size - 3 micrometres (maximum).
3.
Oil content - no gr?ater than 1 part per-mil' ion.
4.
Contamination - free of all corrosive contaminants and hazardous (flammable or toxic) gases.
3.
VALUE/ IMPACT OF THE PROPOSED ACTION 3.1 Value Assessment Since the highest quality instrument air practicable will be produced by the instrument air system design, the proposed additional guidelines will ensure against possible degradation that could cause malfunction of safety-related equipment. Additionally, the implementation of these guidelines will minimize the periodic testing requirements of the instrument air quality over the operating lifetime of the plant.
3.2 lapact Assessment 3.2.1.
Impact on New Plants In order to meet the proposed new guidelines, all new plants will be required to provide safety-related compressed air system designs consisting of non-oil lubricated compressors and automatic molecular sieve air dryers 9.3.1-6 c~ ~~ ~ g y :-)
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e with input and output filters. This will have a minimal impact on applicants since the requirements will be in effect at the time of system design and equipment specification writing.
3.2.2.
Impact on Pre-CP issuance Plants It is important to note that a good initial design will provide an instrument air system that already meets the proposed new guidelines. Most plants in the pre-CP review stage will comply with these guidelines without modification.
The impact on imposing guidance on the remaining few plants (if any) already in the CP review stage will be minimal since, in most cases, instrument air system equipment is a catalog item and is purchased as a package. New specifications may be required for some equipment. System design changes that may be necessary include providing non-oil lubricated compressors instead of oil lubricated compressors, and possible redesign of the air drying and filter'ng equipment. No impact on licensing schedules should result since there is sufficient time between the issuance of the CP and an ordering date to make any necessary changes in the, instrument air system equipment order. The estimated cost of a non oil lubricated compressor verses a lubricated compressor is approximately $6,000.00.
Air drying equipment now used in most system designs will accommodate either standard desiccant media (such as alumina) or molecular sieve drying material. The cost of the desiccant for an air drying system is less than $1,000.00 per charge.
4.
IMPLEMENTATION This revision of SRP Section 9.3.1, " Compressed Air System," provides small improvement to safety of the public or protection of the environment. Consequently, it warrants implementation only on new plants and plants under review that have not yet been issued a construction permit.
Backfitting is not recommended for plants for which the construction permit has been issued or for operating plaats. Periodic testing and maintenance programs will ensure good quality air for plants in this category.
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