NRC Generic Letter 1979-05
| ML031320224 | |
| Person / Time | |
|---|---|
| Issue date: | 01/26/1979 |
| From: | Boyd R Office of Nuclear Reactor Regulation |
| To: | Dail L Duke Energy Corp |
| References | |
| NUDOCS 7902210145, GL-79-005 | |
| Download: ML031320224 (41) | |
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D. C. 20555 CG<-7S-
January 26, 1979 S. Varga Docket No: STN 50- 488 NRC PDR ELD
STN 50 490 LWR #4 File ACRS (16)
C. Moon J. Buchanan, M. Service NSIC
Mr. L. C. Dail, Vice President H. Denton T. Abernathy, TIC
Design Engineering Department E. Case Duke Power Company R. Boyd P. 0. Box 33189 D. Ross Charlotte, North Carolina 282422 R. Mattson R. DeYoung Dear Mr. Dail: D. Vassallo F. WilliAms SUBJECT: INFORMATION RELATING TO CATEGORIZATION OF RECENT REGULATORY
GUIDES BY THE REGULATORY REQUIREMENTS REVIEW COMMITTEE -
PERKINS NUCLEAR STATION
We have recently advised utilities with plants in the post-CP phase of the reactor licensing process of the status of NRC staff review and use of recently-approved regulatory guides, and have indicated how these guides would be used in the Operating License review of their Final Safety Analysis Reports. Such information, while not directly applicable to you at this time, may nonetheless be useful to you for your future planning. The text of our letter to these utilities is the following:
"SUBJECT: IMPLEMENTATION OF STAFF REVIEW REQUIREMENTS - (Name of Plant) - OPERATING LICENSE REVIEW
During the last several years, we have reviewed and approved several new regulatory guides and branch technical positions or other modifications to existing staff positions. Our practice is that substantive changes in staff positions be considered by the NRC's Regulatory Requirements Review Committee (RRRC) which then recommends a course of action to the Director, Office of Nuclear Reactor Regulation (NRR). The recommended action includes an implementation schedule. The Director's approval then is used by the NRR staff as review guidance on individual licensing matters. Some of these actions will affect your application. This letter is intended to bring you up to date on these changes in staff positions so that you may consider them in your Final Safety Analysis Report (FSAR)
preparation.
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1/25/79 /79 1/4./79 I[ E F
-2-
"The RRRC applies a categorization nomenclature to each of its actions. (A copy of the summary of RRRC Meeting No. 31 concerning this categorization is attached as Enclosure 1.) Category 1 matters aare those to be applied to applications in accordance with the implementation section of the published guide. We have enclosed lists of actions which are either Category 2 or Category 3, which are defined as follows:
Category 2: A new position whose applicability is to be determined on a case-by-case basis. You should describe the extent to which your design conforms, or you should describe an acceptable alternate, or you should demonstrate why conformance is not necessary.
Category 3: Conformance or an acceptable alternative is required.
If you do not conform, or do not have an acceptable alternate, then staff-approved design revisions will be required.
"We believe that providing you with a list of the Category 2 and 3 matters approved to date will be useful in your FSAR preparation, and they will be an essential part of our operating license review.
Enclosure 2 is a list of the Category 2 matters. Enclosure 3 is a list of the Catetory 3 matters.
"In addition to the RRRC categories, there also exists an NRR
Category 4 list which are those matters not yet reviewed by the RRRC,
but which the Director, NRR, has deemed to have sufficient attributes to warrant their being addressed and considered in ongoing reviews.
These matters will be treated like Category 2 matters until such time as they are reviewed by the RRRC, and a definite implementation program is developed. A current list of Category 4 matters is attached (Enclosure 4). These also should be considered in your FSAR.
"In some instances the items in the enclosures may not be applicable to your application. Also, we recognize that your application may, in some instances, already conform to the stated staff positions.
In your FSAR you should note such compliance.
"If you have any questions please let us know."
-3- For your information, I am enclosing a set of the enclosures that accompanied these individual letters. These enclosures list the present Category 1-4 matters discussed in the letter.
Sincerely,
.
9oger ctor Division of Project Office of Nuclear Reactor Regulation Enclosures:
As stated cc: See next page
Duke Power Company ccs:
William L. Porter, Esq. Elizabeth S. Bowers, Esq.
Associate General Counsel Chairman Duke Power Company Atomic Safety and Licensing Board Charlotte, North Carolina 28242 U. S. Nuclear Regulatory Commission Washington, D. C. 20555 J. Michael McGarry, III, Esq.
Debevoise & Liberman Dr. Donald P. deSylva
700 Shoreham Building Associate Professor of Marine Science
806 Fifteenth Street, N. W. Rosenstiel School of Marine and Washington, D. C. 20005 Atmospheric Science University of Miama William A. Raney, Jr. Miami, Florida 33149 Special Deputy Attorney General Attorney for the State of Dr. Walter H. Jordan North Carolina 881 W. Outer Drive Department of Justice Oak Ridge, Tennessee 37830
P. 0. Box 629 Raleigh, North Carolina 27602 Allan S. Rosenthal, Chiarman Atomic Safety and Licensing Mary Apperson Davis, Chairman Appeal Board Yadkin River Committee U. S. Nuclear Regulatory Commission Route 4, Box 261 Washington, D. C. 20555 Mocksville, North Carolina 27028 Dr. John H. Buck Thomas S. Erwin, Esq. Atomic Safety and Licensing Appeal Board P. 0. Box 928 U. S. Nuclear Regulatory Commission Raleigh, North Carolina 27602 Washington, D. C. 20555 David Springer Richard S. Salzman, Esq.
The Point Farm Atomic Safety and Licensing Appeal Board Route 4 U. S. Nuclear Regulatory Commission Mocksville, North Carolina 27028 Washington, D. C. 20555 William G. Pfefferkorn, Esq.
2124 Wachovia Building Winston-Salem, North Carolina 27101 Richard P. Wilson, Esq.
Assistant Attorney General S. C. Attorney General's Office P. 0. Box 11549 Columbia, South Carolina 29211
UNITED STATES
NU-tEAR REGULATORY COMMISS..
WASHINGTON. D. C. 20555 SEP 2 4 175 Lee V. Gossick
.Executive Director for Operations REGULATORY REQUIREMENTS REVIEW COMMITTEE MEETING NO. 31, JULY 11, 1975
1. The Committee discussed issues related to the implementation of Regulatory Guides on existing plants and the concerns expressed in the June 24, 1974 memorandum, A. Giambusso to E. G. Case, subject: REGULATORY GUIDE IMPLEMIENTATION, and made the following recommendations and observations:
a. Approval of new Regulatory Guides and approval of revisions of existing guides should move forward expeditiously in order that the provisions of these regulatory guides be available for use as soon as possible in on-going or future staff reviews of license applications. The Committee noted that over the recent past, the approval of proposed regulatory guides whose content is acceptable for these purposes has experienced significant delays in RRRC review pending the determination of the applicability of the guide to existing plants, often requiring significant staff effort. To avoid these delays, the Comnittee concluded that, henceforth, approval of proposed regulatory guides should be uncoupled from the consideration of their backfit applicability.
b. The implementation section of new regulatory guides should address, in general, only the applicability of the guide to applications in the licensing review process using, in so far as possible, a standard approach of applying the guide to those applications docketed 8 months after the issuance date of the guide for comment. Exceptions to this general approach will be handled on a case-by-case basis.
c. The regulatory position of each approved proposed guide (or proposed guide revision) will be characterized by the Committee as to its backfitting potential, by placing it in one of three categories:
Category 1 - Clearly forward fit only. No further staff consideration of possible backfitting is required.
ENCLOSURE 1
Lee V. Gossick -2- Category 2 - Further staff consideration of the need for back- fitting appears to be required for certain identified items of the regulatory position--these individual issues are such that existing plants need to be evaluated to determine their status with regard to these safety issues in order to determine the need for backfitting.
ategory 3 - Clearly backfit. Existing plants should be evaluated to determine whether identified items of the regulatory position are resolved in accordance with the guide or by some equivalent alternative.
From time to time, for a specific guide, there will probably be some variation among these categories or even within a category, and these three broad category characterizations will be qualified as required to meet a particular situation.
d. It is not intended that the Committee categorization appear in the guide itself. The purpose of the categorization is to indicate those items of the reculatory position for which the Committee can make a specific backfit recommendation without additional staff work (Categories 1 and 3), and to indicate those items for which additional staff work is required in order to determine backfit considerations (Category 2).
e. The Committee recommends that for approved guides in Category 2, staff efforts be initiated in parallel with the process leading to publication of the guide in order that specific backfit requirements for existing plants be determined within a reasonable period of time after publication of the guide.
f. The Committee observed that more attention needs to be given to the identification of acceptable alternatives to the positions outlined in the guides in order to provide additional options and flexibility to applicants and licensees, with the possible benefits of additional innovation and exploration in the solution of safety issues.
2. The Committee reviewed the proposed Regulatory Guide l.XX: THERMAL
OVERLOAD PROTECTION FOR MOTORS OM HrOTOR-OPERATED VALVES and recommended approval. This guide was characterized by the Committee as Category 1 - no backfitting, with the stipulation that as an appropriate occasion presented itself in conjunction with the review of some particular aspect of existing plants, the Lhermal overload protection provisions be audited.
ENCLOSURE 1 (CONT'D)
Lee V. Gossick -3-
3. JThe Committee reviewed the proposed Regulatory Guide 1.XX:
INSTRUMENT SPANS AND SETPOINTS and recommended approval subject to the following comment:
Paragraph 5 of Section C (page 4 of the proposed Guide)
should be reworded in light of Committee comments, to the satisfaction of the Director, Office of Standards Development. This guide was characterized by the Committee as Category 1 - no backfit.
4. The Committee reviewed Proposed Regulatory Guide 1.97:
INSTRUWIENTATION FOR LIGHT WATER COOLED NUCLEAR POWER PLANTS
TO ASSESS PLANT CONDITIONS DURING AND FOLLOWING AN ACCIDENT
and deferred further consideration to a later meeting in order to permit incorporation of recent comments by the Division of Technical Review.
Edson G. ase, Chairman Regulatory Requirements Review Committee ENCLOSURE 1 (CONT'D)
SeptembL... 15, 1978 CATEGORY 2 MATTERS
Document Number Revision Date Title RG 1.27 2 1/76 Ultimate Heat Sink for Nuclear Power Plants RG 1.52 1 7/76 Design, Testing, and Maintenance Criteria for Engineered-Safety- Feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light Water Cooled Nuclear Power Plants (Revision 2 has been published but the changes from Revision 1 to Revision 2 may, but need not, be considered.
RG 1.59 2 8/77 Design Basis Floods for Nuclear Power Plants RG 1.63 2 7/78 Electric Penetration Assemblies in Containment Structures for Light Water Cooled Nuclear Power Plants RG 1.91 1 2/78 Evaluation of Explosions Postulated to Occur on Transportation Routes Near Nuclear Power Plant Sites RG 1.102 1 9/76 Flood Protection for Nuclear Power Plants RG 1.105 1 11/76 Instrument Setpoints RG 1.108 1 8/77 Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plants RG 1.115 1 7/77 Protection Against Low-Trajectory Turbine Missiles RG 1.117 1 4/78 Tornado Design Classification RG 1.124 1 1/78 Service Limits and Loading Combinations for Class 1 Linear Type Component Supports RG 1.130 0 7/77 Design Limits and Loading Combinations for Class 1 Plate- and Shell-Type Component Supports (Continued)
ENCLOSURE 2
CATEGORY 2 MATTERS (CONT'D)
Continued Document
.,--- k -- fr.nc; aen na ta Title Numrer FVI 1%*11 v .U_
RG 1.137 0 1/78 Fuel Oil Systems for Standby Diesel Generators (Paragraph C.2)
RG 8.8 2 3/77 Information Relevant to Ensuring that Occupational Radiation Exposures at Nuclear Power Stations Will be as Low as is Reasonably Achievable (Nuclear Power Reactors)
BTP ASB Guidelines for Fire Protection for
9.5-1 1 Nuclear Power Plants (See Implementation Section, Section D)
BTP MTEB 5-7 4/77 Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping RG 1.141 0 4/78 Containment Isolation Provisions for Fluid Systems
-2- ENCLOSURE 2 (CONT'D)
September 15, 1978 CATEGORY 3 MATTERS
Document Number Revision Date Title RG 1.99 1 4/77 Effects of Residual Elements on Predicted Radiation Damage to
-.
Reactor Vessel Materials (Paragraphs C.1 and C.2.
RG 1.101 1 3/77 Emergency Planning 'for Nuclear Power Plants RG 1.114 1 11/76 Guidance on Being Operator at the Controls of a Nuclear Power Plant RG 1.121 0 8/76 Bases for Plugging Degraded PWR
Steam Generator Tubes RG 1.127 1 3/78 Inspection of Water-Control Structures Associated with Nuclear Power Plants RSB 5-1 1 1/78 Branch Technical Position: Design Require- ments of the Residual Heat Removal System RSB 5-2 0 3/78 Branch Technical Position: Reactor Coolant System Overpressurization Protection (Draft copy attached)
RG 1.97 1 8/77 Instrumentation for Light Water Cooled Nuclear Power Plants to Assess Plant Conditions During and Following an Accident (Paragraph C.3 - with additional guidance on paragraph C.3.d to be provided later)
RG 1.68.2 1 7/78 Initial Startup Test Program to Demonstrate Remote Shutdown Capability for Water-Cooled Nuclear Power Plants RG 1.56 1 7/78 Maintenance of Water Purity in Boiling Water Reactors Attachment:
BTP RSB 5-2 (Draft)
ENCLOSURE 3
RAFT
P-
BRANCH TECHNICAL POSITION RSB 5-2
'OVERPRESSURIZATION PROTECTION OF PRESSURIZED WATER REACTORS
WHILE OPERATING AT LOW TEMPERATURES
A. Background General Design Criterion 15 of Appendix A, 10 CFR 50, requires that "the Reactor Coolant System and associated auxiliary, control, and protection systems shall be designed with sufficient margin to assure that the design conditions of the reactor coolant pressure boundary are not exceeded during any condition of normal operation, including anticipated operational occurrences."
Anticipated operational occurrences, as defined in Appendix A of 10 CFR 50,
are "those conditions of normal operation which are expected to occur one or more times during the life of the nuclear power unit and include but are not limited to loss of power to all recirculation pumps, tripping of the turbine generator set, isolation of the main condenser, and loss of all offsite power."
Appendix G of 10 CFR 50 provides the fracture toughness requirements for reactor pressure vessels under all conditions. To assure that the Appendix G limits of the reactor coolant pressure boundary are not exceeded during any anticipated operational occurrences, Technical Specification pressure-temperature limits are provided for operating the plant.
The primary concern of this position is that during startup and shutdown conditions at low temperature, especially in a water-solid condition, the reactor coolant system pressure might exceed the reactor vessel pressure-temperature limitations in the Technical Specifications established for protection against brittle fracture. This inadvertent overpressurization could be generated by any one of a variety of mal- functions or operator errors. Many incidents have occurred in operating plants as described in Reference 1.
Additional discussion on the background of this position is contained in Reference 1.
ENCL 3 (CONT)
-2- L[AF
~B. Branch Position
1. A system should be designed and installed which will prevent exceeding the applicable Technical Specifications and Appendix G
limits for the reactor coolant system while operation at low temperatures. The system should be capable of relieving pressure during all anticipated overpressurization events at a rate sufficient to satisfy the Technical Specification limits, particularly while the reactor coolant system is in a water-solid condition.
2. The system must be able to perform its function assuming any single active component failure. Analyses using appropriate calculational techniques must be provided which demonstrate that the system will provide the required pressure relief capacity assuming the most limiting single active failure. The cause for initiation of the event, e.g., operator error, component malfunction, will not be considered as the single active failure. The analysis should assume the most limiting allowable oDerating conditions and systems configuration at the time of the postulatea cause of the overDressure event. All potential overpressurization events must be considered when establishing the worst case event. *Some events may be prevented by protective interlocks or by locking Out power.
tihse events should be reviewed on an individual basis. If the lnLerlock/piower lockout is acceptable, it car, be excluded from f lilp aialyses provided the controls to prevent the event are in the plant Technical Specifications.
3. The system must meet the design requirements of IEEE 279 (see Implementation). The system may be manually enabled, however, the electrical instrumentation and control system must provide alarms to alert the operator to:
a. properly enable the system at the correct plant condition during cooldown, b. indicate if a pressure transient is occurring.
4. To assure operational readiness, the overpressure protection system must be tested in the following manner:
a. A test must be performed to assure operability of the system electronics prior to each shutdown.
b. A test for valve operability must, as a minimum be conducted as specified in the ASME Code Section XI.
c. Subsequent to system, valve, or electronics maintenance, a test on that portion(s) of the system must be performed prior to declaring the system operational.
ENCL 3 (CONT)
-3-
5. The system must meet the requirements of Regulatory Guide 1.26.
'Quality Group Classifications and Standards for Water-, Steam-,
and Radioactive-Waste-Containing Components of Nuclear Power Plants"
and Section III of the ASME. Code.-
6. The overpressure protection system must be designed to function during an Operating Basis Earthquake. It must not compromise the design criteria of any other safety-grade system with which it would interface, such that the requirements of Regulatory Guide
1.29, "Seismic Design Classification" are met.
7. The overpressure protection system must not depend on the availability of offsite power to perform its function.
8. Overpressure protection systems which take credit for an active component(s) to mitigate the consequences of an overpressurization event must include additional analyses considering inadvertent system initiation/actuation or provide justification to show that existing analyses bound such an event.
C. Implementation The Branch Technical Position, as specified in Section B, will be used in the review of all Preliminary Design Approval (PDA), Final Design Approval (FDA), Manufacturing License (ML), Operating License (OL), and Construction Permit (CP) applications involving plant designs incorporating pressurized water reactors. All aspects of the position will be applicable to all applications, including CP applications utilizing the replication option of the Commission's standardization program, that are docketed after March 14, 1978. All aspects of the position, with the exception of reasonable and justified deviations from IEEE 279 requirements, will be applicable to CP, OL, ML, PDA, and FDA applications docketed prior to March 14, 1978 but for which the licensing action has not been completed as of March 14, 1978. Holders of appropriate PDA's will be informed by letter that all aspects of the position with the exception of IEEE 279 will be applicable to their approved standard designs and that such designs should be modified, as necessary, to conform to the position. Staff approval of proposed modifications can be applied for either by application by the PDA-holder on the PDA-docket or by each CP applicant referencing the standard design on its docket.
The following guidelines may be used, if necessary, to alleviate impacts on licensing schedules for plants involved in licensing proceedings nearing completion on March 14, 1978:
ENCL 3 (CONT)
-4v LUA
1. Those applicants issued an OL during the period between
1978 and a date 12 months thereafter may merely commit March 14, the position prior to OL issuance but shall, by license to meeting be required to install all required staff-approved condition, codifications prior to plant startup following the first scheduled refueling outage.
2. Those applicants issued an OL beyond March 14,
1979 all required staff-approved modifications prior to shall install initial plant startup.
3. Those applicants issued a CP, PDA, or ML during the period between March 14, 1978 and a date 6 months thereafter may merely to meeting the position but shall, by license condition, commit required to amend the application, within 6 months be of the issuance of the CP, PDA, or ML, to include a description date of proposed modifications and the bases for their design, of the request for staff approval. and a
4. Those applicants issued a CP, PDA, or ML after September 14, 1978 shall have staff approval of proposed modifications prior to issuance of the CP, PDA, or ML.
D. References
1. NUREG-0138, Staff Discussion of Fifteen Technical in Attachment to November 3, 1976 Memorandum from Issues Listed Director, NRR,
to NRR Staff.
ENCL 3 (CONT)
CATEGORY 4 MATTERS
A. Regulatory Guides not categorized Issue Date Number Revision Title
4/74 1.12 1 Instrumentation for Earthquakes
12/75 1.13 1 Spent Fuel Storage Facility Design Basis
8/75 1.14 1 Reactor Coolant Pump Flywheel Integrity
1/75 1.75 1 Physical Independence of Electric Systems
4/74 1.76 0 Design Basis Tornado for Nuclear Power Plants
9/75 1.79 1 Preoperational Testing of Emergency Core Cooling Systems for Pressurized Water Reactors
6/74 1.80 0 Preoperational Testing of Instrument Air Systems
6/74 1.82 0 Sumps for Emergency Core Cooling and Containment Spray Systems
7/75 1.83 1 Inservice Inspection of Pressurized Water Reactor Steam Generator Tubes
11/74 1.89 0 Qualification of Class lE Equipment for Nuclear Power Plants
12/74 1.93 0 Availability of Electric Power Sources
2/76 1.104 0 Overhead Crane Handling Systems for Nuclear Power Plants ENCLOSURE 4
-2- B. SRP Criteria Implementa- Applicable tion Date Branch SRP Section Title
1. 1.1/24/75 MTEB 5.4.2.1 BTP MTEB-5-3,-Monitoring of Secondary Side Water Chemistry in PWR Steam Generators
2. 11/24/75 CSB 6.2.1 BTP CSB-6-1, Minimum
6.2.1A Containment Pressure Model
6.2.1B for PWR ECCS Performance
6.2.1.2 Evaluation
6.2.1.3
6.2.1.4
6.2.1.5
3. 11/24/75 CSB 6.2.5 BTP CSB-6-2, Control of Combustible Gas Concentra- tions in Containment Following a Loss-of-Coolant Accident
4. 11/24/75 CSB 6.2.3 BTP CSB-6-3, Determination of Bypass Leakage Path in Dual Containment Plants
5. 11/24/75 CSB 6.2.4 BTP CSB-6-4, Containment Purging During Normal Plant Operations
6. 11/24/75 ASB 9.1.4 BTP ASB-9.l, Overhead Handling Systems for Nuclear Power Plants
7. 11/24/75 ASB 10.4.9 BTP ASB-10.1, Design Guidelines for Auxiliary Feedwater System Pump Drive and Power Supply Diversity for PWR's
8. 11/24/75 SEB 3.5.3 Procedures for Composite Section Local Damage Prediction (SRP
Section 3.5.3, par. Il.l.C)
ENCLOSURE 4 (CONT)
-3- Implementa- Applicable tion Date Branch SRP Section Title
9. 11/24/75 SEB 3.7.1 Development of Design Time History for Soil-Structure Interaction Analysis (SRP
Section 3.7.1, par. 11.2)
10. 11/24/75 SEB 3.7.2 Procedures for Seismic System Analysis (SRP Section 3.7.2 par. II)
11. 11/24/75 SEB 3.7.3 Procedures for Seismic Sub- system Analysis (SRP Section 3.7.3, par. II)
12. 11/24/75 SEB 3.8.1 Design and Construction of Concrete Containments) SRP
Section 3.8.1, par. II)
13. 11/24/75 SEB 3.8.2 Design and Construction of Steel Containments (SRP Section
3.8.2, par. II)
14. 11/24/75 SEB 3.8.3 Structural Design Criteria for Category I Structures Inside Containment (SRP Section 3.8.3, par. II)
15. 11/24/75 SEB 3.8.4 Structural Design Criteria for Other Seismic Category I Structures (SRP Section 3.8.4, par. II)
16. 11/24/75 SEB 3.8.5 Structural Design Criteria for Foundations (SRP Section 3.8.5, par. II)
17. 11/24/75 SEB 3.7 Seismic Design Requirements for
11.2 Radwaste Sysems and Their Housing
11.3 Structures (SRP Section 11.2, BTP
11.4 ETSB 11-1,par. B.v)
ENCLOSURE 4 (CONT)
-4- Implementa- Applicable tion Date Branch SRP Section Title
18. 11/24/75 SEB 3.3.2 Tornado Load Effect Combi- nations (SRP Section 3.3.2, par. II.2.d)
19. 11/24/75 SEB 3.4.2 Dynamic Efects of Wave Action (SRP Section 3.4.2, par. II)
20. 10/0l/75 ASB 10.4.7 Water Hammer for Steam Generators with Preheaters (SRP
Section 10.4.7 par. I.2.b)
21. 11/24/75 AB 4.4 Thermal-Hydraulic Stability (SRP
Section 4.4, par. II.5)
22. 11/24/75 RSB 5.2.5 Intersystem Leakage Detection (SRP
Section 5.2.5 par. 1I.4) and R.G. 1.45
23. 11/24/75 RSB 3.2.2 Main Steam Isolation Valve Leakage Control System (SRP Section 10.3 par. 11I.3 and BTP RSB-3.2)
C. Other Positions Implementa- Applicable tion Date Branch SRP Section Title
1. 12/1/76 SEB 3.5.3 Ductility of Reinforced Concrete and Steel Structural Elements Subjected to Impactive or Impulsive Loads
2. 8/01/76 SEB 3.7.1 Response Spectra in Vertical Direction
3. 4/01/76 SEB 3.8.1 BWR Mark III Containment Pool
3.8.2 Dynamics
4. 9/01/76 SEB 3.8.4 Air Blast Loads
5. 10/01/76 SEB 3.5.3 Tornado Missile Impact
6. 6/01/77 RSB 6.3 Passive Failures During Long- Term Cooling Following LOCA
ENCLOSURE 4 (CONT)
-5-
- Implementa- Applicable tion Date Branch SRP Section Title
7. 9/01/77 RSB 6.3 Control Room Position Indica- tion of Manual (Handwheel) Valves in the ECCS
8. 4/01/77 RSB 15.1.5 Long-Term Recovery from Steamline Break: Operator Action to Prevent Overpressurization
9. 12/01/77 RSB 5.4.6 Pump Operability Requirements
5.4.7
6.3
10. 3/28/78 RSB 3.5.1 Gravity Missiles, Vessel Seal Ring Missiles Inside Containment
11. 1/01/77 AB 4.4 Core Thermal-Hydraulic Analysis
12. 1/01/78 PSB 8.3 Degraded Grid Voltage Conditions
13. 6/01/76 CSB 6.2.1.2 Asymmetric Loads on Components Located Within Containment Sub- compartments
14. 9/01/77 CSB 6.2.6 Containment Leak Testing Program
15. 1/01/77 CSB 6.2.1.4 Containment Response Due to Main Steam Line Break and Failure of MSLIV to Close
16. 11/01/77 ASB 3.6.1 Main Steam and Feedwater Pipe
3.6.2 Failures
17. 1/01/77 ASB 9.2.2 Design Requirements for Cooling Water to Reactor Coolant Pumps
18. 8/01/76 ASB 10.4.7 Design Guidelines for Water Hammer in Steam Generators with Top Feedring Design (BTP ASB-10.2)
19. 1/01/76 ICSB 3.11- Environmental Control Systems-for Safety-Related Equipment ENCLOSURE 4 (CONT)
DESCRIPTION OF POSITIONS IDENTIFIED AS NRR CATEGORY 4 MATTERS IN ENCLOSURE 4, PARAGRAPH C
Numbering scheme corresponds to that used in Item C of Enclosure 4.
ENCLOSURE 4 (CONT)
C.1 DUCTILITY OF REINFORCED CONCRETE AND STEEL STRUCTURAL ELEMENTS
SUBJECTED TO IMPACTIVE OR IMPULSIVE LOADS
INTRODUCTION
In the evaluation of overall response of reinforced concrete structural elements (e.g., missile barriers, columns, slabs, etc.) subjected to impactive or impulsive loads, such as impacts due to missiles, assumption of non-linear response (i.e., ductility ratios greater than unity) of the structural elements is generally acceptable provided that the safety functions of the structural elements and those of safety-related systems and components supported or protected by the elements are maintained.
The following summarizes specific SEB interim positions for review and acceptance of ductility ratios for reinforced concrete and steel structural elements subjected to impactive and impulsive loads.
SPECIFIC POSITIONS
1. REINFORCED CONCRETE MEMBERS
1.1 For beams, slabs, and walls where flexure controls design, the permissible ductility ratio ( U ) under impactive and impulsive loads should be taken as
= 0.05 for p- >' .X005
0 P
10 for p - ' < .005 where p and P'are the ratios of tensile and compressive reinforcing as defined in ACI-318-71 Code.
1.2 If use of a ductility ratio greater than 10 (i.e., P> 100)
is required to demonstrate design adequacy of structural elements against impactive or impulsive loads, e.g., missile impact, such a usage should be identified in the plant SAR.
Information justifying the use of this relatively high ductility value shall be provided for SEB staff review.
ENCLOSURE 4 (CONT)
-2-
1.3 For beam-columns, walls, and slabs carrying axial compression loads and subject to impulsive or impactive loads producing flexure, the permissible ductility ratio in flexure should be as follows:
(a) When compression controls the design, as defined by an interaction diagram, the permissible ductility ratio shall be 1.3.
(b) When the compression loads do not exceed O.lfcAg or one- third of that which would produce balanced conditions, which- ever is smaller, the permissible ductility ratio can be as given in Section 1.1.
(c) The permissible dutility ratio shall vary linearly from 1.3 to that given in Section 1.1 for conditions between those specified in (a) and (b). (See Fig 1.)
1.4 For structural elements resisting axial compressive impulsive or impactive loads only, without flexure, the permissible axial ductility ratio shall be 1.3.
1.5 For shear carried by concrete only
= 1.0
For shear carried by concrete and stirrups or bent bars
= 1.3 For shear carried entirely by stirrups
= 3.0
2.0 STRUCTURAL STEEL MEMBERS
2.1 For flexure compression and shear U = 10.0
2.2 For columns with slenderness ratio (l/r) equal to or less than 20
U = 1.3 ENCLOSURE 4 (CONT)
pa(ttes)
z boo,
° whi clev-er I..
iIs the smaller MOl M i;T- k) 9Ctl>i FlAT1011FOR~s 'Dctr
-3- where I - effective length of the member r c the least radius of gyration For columns with slenderness ratio greater than 20
=Z 1.0
2.3 For members subjected to tension
.5 to where cu= uniform ultimate strain of the material cy = strain at yield of material C.2 RESPONSE SPECTRA IN THE VERTICAL DIRECTION
Subsequent to the issuance of Regulatory Guide 1.60, the report
"Statistical Studies of Vertical and Horizontal Earthquake Spectra"
was issued in January 1976 by NRC as NUREG-0003. One of the important conclusions of this report is that the response spectrum for vertical motion can be taken as 2/3 the response spectrum for horizontal motion over the entire range of frequencies in the Western United States. According to Regulatory Guide 1.60, the vertical response spectrum is equal to the horizontal response spectrum between
3.5 cps and 33 cps. For the Western United States only, consistent with the latest available data in NUREG-0003, the option of taking the vertical design design response spectrum as 2/3 the horizontal response spectrum over the entire range of frequencies will be accepted.
For other locations, the vertical response spectrum will be the same as that given in Regulatory Guide 1.60.
C.3 BWR MARK III CONTAINMENT POOL DYNAMICS
1. POOL SWELL
a. Bubble pressure, bulk swell and froth swell loads, drag pressure and other pool swell loads should be treated as abnormal pressure loads, Pa. Appropriate load combinations and load factors should be applied accordingly.
b. The pool swell loads and accident pressure may be combined in accordance with their actual time histories of occurrence.
ENCLOSURE 4 (CONT)
4 !
2, SAFETY RELIEF VALVE (SRV) DISCHARGE
a. The SRV loads should be treated as live loads in all load combinations 1 .5Pa where a load factor of 1.25 should be applied to the appropriate SRV loads.
b. A single active failure causing one SRV discharge must be considered in combination with the Design Basis Accident (DBA).
c. Appropriate multiple SRV discharge should be considered in combination with the Small Break Accident (SBA) and Inter- mediate Break Accident (IBA).
d. Thermal loads due to SRV discharge should be treated as TO
for normal operation and Ta for accident conditions. 0
e. The suppression pool liner should be designed in accordance with the ASME Boiler and Pressure Vessel Code, Division 1 Subsection NE to resist the SRV negative pressure, considering strength, buckling and low cycle fatigue.
C.4 AIR BLAST LOADS (Pa, Ta, To as defined in ACI 359-740)
The following interim position on air blast loadings on Nuclear Power Plant Structures should be used as guidance in.evaluating analyses.
1. An equivalent static pressure may be used for structural analysis purposes. The equivalent static pressure should be obtained from the air blast reflected pressure or the overpressure by multiplying these pressures by a factor of two. Any proposed use of a dynamic load factor less than two should be treated on a case by case basis.
Whether the reflected pressure or the overpressure is to be used for individual structural elements depends on whether an incident blast wave could strike the surface of the element.
.2. No load factor need be specified for the air blast loads, and the load combination should be:
U= D + L+ B
where, U is the strength capacity of a section D is dead load L is live load B is air blast load.
3. Elastic analysis for air blast is required for concrete structures of new plants. For steel structural elements, and also for rein- forced concrete elements in existing plants, some inelastic response may be permitted with appropriate limits on ductility ratios.
ENCLOSURE 4 (CONT)
-5-
4. Air blast generated ground shock and air blast wind pressure may be ignored. Air blast generated missiles may be important in situations where explosions are postulated to occur in vessels which may fragment.
5. Overturning and sliding stability should be assessed by multiplying the structure's full projected area by the equivalent static pressure and assuming only the blast side of the structure is loaded. Justification for reducing the average equivalent static pressure on curved surfaces should be considered on a case by case basis.
6. Internal supporting structures should also be analyzed for the effects of air blast to determine their ability to carry loads applied directly to exterior panels and slabs. Moreover.in vented structures, interior structures may require analysis even if they do not support exterior structures.
7. The equivalent static pressure should be considered as potentially acting both inward and outward.
C.5 TORNADO MISSILE PROTECTION
As an interim measure,the minimum concrete wall and roof thickness for tornado missile protection will be as follows:
Wall Thickness Roof Thickness Concrete Strength (psi) (inches) (inches)
3000 27 24 Region I 4000 24 21
5000 21 18
3000 24 21 Region II 4000 21 18
5000 19 16
3000 21 18 Region III 4000 18 16
5000 16 14 These thicknesses are for protection against local effects only. Designers must establish independently the thickness requirements for overall structura response. Reinforcing steel should satisfy the provisions of Appendix C, ACI
349 (that is, .2% minimum, EWEF). The regions are described in Regulatory Guide 1.76.
ENCLOSURE 4 (CONT)
- 6 -
C.6 PASSIVE ECCS FAILURES DURING LONG-TERM COOLING FOLLOWING A LOCA
Passive failures in the ECCS, having leak rates equal to or less than those from the sudden failure of a pump seal and which may occur the long-term cooling period following a postulated LOCAshould beduring con- sidered. To mitigate the effects of such leaks, a leak detection system having design features and bases as described below should be Included in the plant design.
The leak detection system should Include detectors and alarms which alert the operator of passive ECCS leaks in sufficient time so that would appro- priate diagnostic and corrective actions may be taken on a timely basis.
The diagnostic and corrective actions would include the identification isolation of the faulted ECCS line before the performance of more than and subsystem is degraded. The design bases of the leak detection system one include: should
(1) Identification and justification of the maximum leak rate;
(2) Maximum allowable time for operator action and justification therefor;
(3) Demostration that the leak detection system is sensitive enough to initiate and alarm on a timely basis, i.e., with sufficient lead to allow the operator to identify and isolate the faulted line time before the leak can create undesireable consequences such as flooding of re- dundant equipment. The minimum time to be considered is 30 minutes;
(4) Demonstration that the leak detection system can identify the faulted ECCS train and that the leak can be isolated; and
(5) Alarms that conform with the criteria specified for the control room alarms and a leak detection system that conforms with the require- ments of IEEE-279, except that the single failure criterion need not be imposed.
C.7 CONTROL ROOM POSITION INDICATION OF MANUAL (HANDWHEEL) VALVES
Regulatory Guide 1.47 specifies automatic position indication of each bypass or deliberately induced inoperable condition if the following three conditions are met:
(1) The bypass or inoperable condition affects a system that is designed to perform an automatic safety function.
ENCLOSURE 4 (CONT)
-7-
(2) The bypass or inoperable condition can reasonably be expected to occur more frequently than once per year.
(3) The bypass or inoperable condition is expected to occur when the system is normally required to operate.
Revision one of the Standard Review Plan in Section 6.3 requires conformance with Regulatory Guide 1.47 with the intent being that any manual (handwheel) valve Which could Jeopardize the operation of the ECCS, if inadvertently left in the wrong position, must have position indication in the control room. In the PDA extension reviews it is important to confirm that standard designs include this design feature. Most standard designs do but this matter was probably not specifically addressed in some of the first PDA reviews.
C.8 LONG-TERM RECOVERY FROM STEAM LINE BREAK - OPERATOR ACTION TO
PREVET OVERP SURAION PWR)
A steam line break causes cooldown of the primary system, shrinkage of RCS inventory and depletion of pressurizer fluid. Subsequent to plant trip, ECCS actuation, and main steam system isolation, the RCS inven- tory increases and expands, refilling the pressurizer. Without operator action, replenishment of RCS inventory by the ECCS and expansion at low temperature could repressurize the reactor to an unacceptable pressure- temperature region thereby compromising reactor vessel integrity. Anal- yses are required to show that following a main steam line break that (i) no additional fuel failures result from the accident, and (ii) the pressures following the initiation of the break will not compromise the integrity of the reactor coolant pressure boundary giving due considera- tion to the changes in coolant and material temperatures. The analyses should be based on the assumption that operator action will not be taken until ten minutes after initiation of the ECCS.
C.9 PUMP OPERABILITY REQUIREMENTS
In some reviews, the staff has found reasonable doubt that some types of engineered safety feature pumps would continue to perform their safety function in the long term following an accident. In such instances there has been followup, including pump redesign in some cases, to assure that long term performance could be met. The following kinds of infor- mation may be sought on a case-by-case basis where such doubt arises.
a. Describe the tests performed to demonstrate that the pumps are capable of operating for extended periods under post-LOCA conditions, including the effects of debris. Discuss the damage to pump seals caused by debris over an extended period of operation.
ENCLOSURE 4 (CONT)
-8- b. Provide detailed diagrams of all water cooled seals and compo- nents in the pumps.
c. Provide a description of the composition of the pump shaft seals and the shafts. Provide an evaluation of loss.of shaft seals.
d. Discuss how debris and post-LOCA environmental conditions factored into the specificatfons and design of the pump. were C.lO GRAVITY MISSILES, VESSEL SEAL RING MISSILES INSIDE CONTAINMENT
Safety related systems should be protected against loss of function internal missiles from sources such as those associated with due to components and rotating equipment. Such sources would include pressurized limited to retaining bolts, control rod drive assemblies, the but not be vessel seal ring, valve bonnets, and valve stems. A description of the methods to afford protection against such potential missiles, including used therefor, should be provided (e.g., preferential orientation the bases tial missile sources, missile barriers, physical separation ofof the poten- safety systems and components). An analysis of the effects of redundant tial missiles on safety related systems, including metastably such poten- equipment which could fall upon impingement, should also be supported provided.
ENCLOSURE 4 (CONT)
-9- C.Tl CORE THERMAL-HYDRAULIC ANALYSES
In evaluating the thermal-hydraulic performance of the reactor core~the following additional areas should be addressed:
1. The effect of radial pressure gradients at the exit-of open lattice cores.
2. The effect of radial pressure gradients in the upper plenum.
3. The effect of fuel rod bowing.
In additiona commitment to perform tests to verify the transient analysis methods and codes is required.
C.12 DEGRADED GRID VOLTAGE CONDITIONS
As a result of the Millstone Unit Number 2 low grid voltage occurrence, the staff has developed additional requirements concerning (a) sustained degraded voltage conditions at the offsite power source, and (b) inter- action of the offsite and onsite emergency power systems. These additional requirements are defined in the following staff position.
1. We require that a second level of voltage protection for the onsite power system be provided and that this second level of voltage pro- tection satisfy the following requirements:
a) The selection of voltage and time set points shall be determined from an analysis of the voltage requirements of the safety-related loads at all onsite system distribution levels;
b) The voltage protection shall include coincidence logic to preclude spurious trips of the offsite power source;
ENCLOSURE 4 (CONT)
-10-
c) The time delay selected shall be based on the following conditions:
(i) The allowable time delay, including margin, shall not exceed the maximum time delay that is assumed in the SAR accident analyses;
(ii) The time delay shall minimize the effect of short duration disturbances from reducing the availability of the offsite power source(s); and (iii) The allowable time duration of a degraded voltage condition at all distribution system levels shall not result in failure of safety systems or components;
(iv) The voltage sensors shall automatically initiate the disconnection of offsite power sources whenever the voltage set point and time delay limits have been exceeded;
(v) The voltage sensors shall be designed to satisfy the applicable requirements of IEEE Std. 279-1971 "Criteria for Protection Systems for Nuclear Power Generating Stations"; and (vi) The Technical Specifications shall include limiting conditionsfor operation, surveillance requirements, trip set points with minimum and maximum limits, and allowable values for the second-level voltage protection sensors and associated time delay devices.
2. We require that the system design automatically prevent load shedding of the emergency buses once the onsite sources are supplying power to all sequenced loads on the emergency buses.
The design shall also include the capability of the load shedding feature to be automatically reinstated if the onsite source supply breakers are tripped. The automatic bypass and reinstatement feature shall be verified during the periodic testing identified in Item 3 of this position.
3. We require that the Technical Specifications include a test require- ment to demonstrate the full functional operability and independence of the onsite power sources at least once per 18 months during shut- down. The Technical Specifications shall Include a requirement for tests: (a) simulating loss of offsite power; (b) simulating loss of offsite power in conjunction with a safety injection actuation signal; and (c) simulating interruption and subsequent reconnection of onsite power sources to their respective buses.
ENCLOSURE 4 (CONT)
-11-
4. The voltage levels at the safety-related buses should be optimized for the full load and minimum load conditions that are expected throughout the anticipated range of voltage variations of the offsite power source by appropriate adjust- ment of the voltage tap settings of the intervening transformers.
We require that the adequacy of the design in this regard be verified by actual measurement, and by correlation- of measured values with analysis results.
C.13 ASYMMETRIC LOADS ON COMPONENTS
LOCATED WITHIN CONTAINMENT SUBCOMPARTMENTS
In the unlikely event of a pipe rupture inside a major component sub- compartment., the initial blowdown transient would lead to pressure loadings on both the structure and the enclosed component(s).
staff's generic Category A Task Action Plan A-2 is designed to The develop generic resolutions for this matter. Our present schedule calls for completing A-2 for PWR's during the first quarter, 1979. Pending completion of A-2, the staff is implementing the following program:
1. For PWRs at the CP/PDA stage of review, the staff requires appli- cants to commit to address the safety issue as part of their appli- cation for an operating license.
2. For PWRs at the OL/FDA stage of review, the staff requires case-by-case analyses, including implementation of any indicated corrective measusres prior to the issuance of an operating license.
3. For BWRs, for which this issue is expected to be of lesser safety significance, the asymmetric loading conditions will be evaluated on a case-specific basis prior to the Issuance of an operating license.
For those cases which analyses are required, we request the performance of a subcompartment, multi-node pressure response analysis of the pressure transient resulting from postulated hot-leg and cold-leg (pump suction and discharge) reactor coolant system pipe ruptures within the reactor cavity, pipe penetrations, and steam generator compartments. Provide similar analyses for the pressurizer surge and spray lines, and other high energy lines located in containment compartments that may be subject to pressurization. Show how the results of these analyses are used in the design of structures and component supports.
ENCLOSURE 4 (CONT)
-12- C.14 CONTAINMENT LEAK TESTING PROGRAM
To avoid difficulties experienced in this area in recent OL reviews, the staff has increased its scope of inquiry at the CP/PDA stage of review. For this purpose, the following information with regard to the containment leak testing program should be supplied.
a. Those systems that will remain fluid filled for the Type A test should be identified and justification given.
b. Show the design provisions that will permit the personnel air- lock door seals and the entire air lock to be tested.
c. For each penetration,i.e., fluid system piping, instrument, electrical, and equipment and personnel access penerations, identify the Type B and/or Type C local leak testing that will be done.
d. Verify that containment penetrations fitted with expansion bellows will be tested at Pa. Identify any penetration fitted with expansion bellows that does not have the design capability for Type B testing and provide justification.
C.15 CONTAINMENT RESPONSE DUE TO MAIN STEAM LINE
BREAK AND MSLIV FAILURE
In recent CP and OL application reviews, the results of analyses for a postulated main steam line break accident (MSLB)
for designs utilizing pressurized water reactors with conventional containments show that the peak calculated containment temperature can exceed for a short time period the environmental qualification temperature-time envelope for safety related instruments and components. This matter was also discussed in Issue No. 1 of NUREG-0138 and Issue No. 25 of NUREG-0153. The signifiance of the matter is that it could result in a requirement for requalifying safety-related equipment to higher time-temperature envelopes.
The staff's generic Category A Task Action Plans A-21 and A-24 are designed to develop generic resolutions for these matters. The presently scheduled completion dates for A-21 and A-24 (Short Term Portion) are first quarter, 1979 and fourth quarter, 1978, respectively.
Pending completion of A-21 and A-24, some interim guidance will be used as detailed below.
We have developed and are implementing a plan in which all applicants for construction permits and operating licenses and those already issued con- struction permits must provide information to establish a conservative temperature-time envelope.
ENCLOSURE 4 (CONT)
-13- Therefore, describe and justify the analytical model used to conservatively determine the maximum containment temperature and pressure for a spectrum of postulated main steam line breaks for various reactor power levels. Include the following in the discussion.
(1) Provide single active failure analyses which specifically identify those safety grade systems and components relied upon to limit the mass and energy release and containment pressure/
temperature response. The single failure analyses should include, but not necessarily be limited to: main steam and connected systems isolation; feedwater auxiliary feedwater, and connected systems isolation; feedwater, condensate, and auxiliary feedwater pump trip, and auxiliary feedwater run-out control system; the loss of or availability of offsite power; diesel failure when loss of offsite power is evaluated; and partial loss of containment cooling systems.
(2) Discuss and justify the assumptions made regarding the time at which active containment heat removal systems become effective.
(3) Discuss and justify the heat transfer correlation(s) (e.g., Tagami, Uchida) used to calculate the heat transfer from the containment atmosphere to the passive heat sinks, and provide a plot of the heat transfer coefficient versus time for the most severe steam line break accident analyzed.
(4) Specify and justify the temperature used in the calculation of condensing heat transfer to the passive heat sinks; i.e.,
specify whether the saturation temperature corresponding to the partial pressure of vapor, or the atmosphere temperature(which may be superheated)was used.
(5) Discuss and justify the analytical model including the thermodynamic equations used to account for the removal of the condensed mass from the containment atmosphere due to condensing heat transfer to the passive heat sinks;
(6) Provide a table of the peak values of containment atmosphere temperature and pressure for the spectrum of break areas and power levels analyzed;
(7) For the case which results in the maximum containment atmosphere temperature, graphically show the containment atmosphere temperature, the containment liner temperature, and the containment concrete temperature as a function of time. Compare the calculated contain- ment atmosphere temperature response to the temperature profile used in the environmental qualification program for those safety related instruments and mechanical components needed to mitigate the consequences of the assumed main steam line break and effect safe reactor shutdown;
ENCLOSURE 4 (CONT)
-14-
(8) For the case which results in maximum containment atmosphere pressure, graphically show the containment pressure as a function of time; and
(9) For the case which results in the maximum containment atmosphere pressure and temperature, provide the mass and energy release data in tabular form.
In order to demonstrate that safety-related equipment has been adequately qualified as described above, provide the following information regard- ing its environmental qualification.
(1) Provide a comprehensive list of equipment required to be operational in the event of a main steamline break (MSLB) accident. The list should include, but not necessarily be limited to, the following safety related equipment:
(a) Electrical containment penetrations;
(b) Pressure transmitters;
(c) Containment isolation valves;
(d) Electrical power cables;
(e) Electrical instrumentation cable; and (f) Level transmitters.
Describe the qualification testing that was, or will be, done on this equipment.
Include a discussion of the test environment, namely, the temperature, pressure, moisture content, and chemical spray, as a function of time.
(2) It is our position that the thermal analysis of safety related equipment which may be exposed to the containment atmosphere following a main steam line break accident should be based on the following:
(a) A condensing heat transfer coefficient based on the recommendations in Branch Technical Position CSB 6-1,
"Minimum Containment Pressure Model for PWR ECCS Performance Evaluation,"should be used.
(b) A convective heat transfer coefficient should be used when the condensing heat flux is calculated to be less than the convective heat flux. During the blowdown period it is appropriate to use a conservatively evaluated forced convection heat transfer correlation. For example, ENCLOSURE 4 (CONT)
-15- Nu = C(Re)
Where Nu - Nusselt No.
Re = Reynolds No.
C a empirical constants dependent on geometry and Reynolds No.
on velocity, it is Since the Reynolds number is dependent currents which will be necessary to evaluate the forced flow The CVTR experiments generated by the steam generaor blowdown. Convective currents of provide limited data in this regard. locally. We recommend from 10 ft/sec to 30 ft/sec were measured conservatively to that the CVTR test results be extrapolatedthe convective heat obtain forced flow currents to determine period. After the transfer coefficient during the blowdowna negligibly low value, blowdown has ceased or been reduced to is acceptable.
a natural convection heat transfer correlation analysis is done in conjunction
(3) For each component where thermal temperature lower than the peak with an environmental test at a steam line break accident, calculated temperature following a main component with the accident compare the test thermal response of the the basis by which the thermal analysis of the component. Provide from the environmental component thermal response was developed graphically show the qualification test program. For instance, locations, method thermocouple data and discuss the thermocouple or provide a of attachment, and performance characteristics, used to evaluate the detailed discussion of the analytical model This evaluation should component thermal response during the test.
failure such as thin be performed for the potential points of parts where thermal stressing, cross-sections and temperature sensitive chemical interaction at temperature-related degradation, steam oreffects could result in the elevated temperatures, or other thermal electrically. If the failure of the component mechanically or in the prediction of component thermal response comparison results conditions than a more severe thermal transient for the accident that the affected for the qualification test, provide justification during a MSLB accident, component will perform its intended function would appropriately or provide protection for the component whch limit the thermal effects.
ENCLOSURE 4 (CONT)
-16- FAILURES
C.16 ENVIRONMENTAL EFFECT OF PIPE
regions of the main steam Identify the "break exclusion" that contain break and feedwater lines. Compartments and feedwater lines and any safety steam exclusion regions of main to with- compartments should be designed related equipment in these (pressure, temperature, humidity and stand the environmental effects cross sectional a break area equal to the flooding) of a crack with area of the'break excluded'pipe.
WATER
C.17 DESIGN REQUIREMENTS FOR COOLING
TO REACTOR COOLANT PUMPS
seal injection coolant system (RCS) pump Demonstrate that the reactor transients and accidents maintained for all flow will be automatically are availAhla t" perm'it or that enough time and Information corrective action by an operator.
of the criteria for th-at portion We have established the following system which interfaces with the reactor component cooling water (CCW) water to pump seals and bearings coolant pumps to supply cooling anticipated transients, and accidents.
during normal operation, system in the component cooling water
1. A single active failure damage or a breach of the reactor shall not result in fuel loss (RCPB) caused by an extended coolant pressure boundary active failures pumps. Single of cooling to one or more actuation of motor-operated include operator error, spurious valves, and loss of CCW pumps.
shall accident (unanticipated occurrence)
2. A pipe crack or other breach of the RCPB or excessive fuel not result in either a of cooling to two or more RC
damage when an extended loss falure shall be considered when pumps occurs. A single active of this accident. Moderate leakage evaluating the consequences in accordance with Branch Technical cracks should be determined Position ASB 3-1.
inter- established above, an NSSS
In order to meet the criteria imposed on the balance-of-plant CCW
face requirement should be and motor provides cooling water to the RC pump seals system that following con- pump bearings, so that the system will meet the and ditions:
ENCLOSURE 4 (CONT)
-17- portion of the component cooling water (CCW) system which
1. That reactor coolant pumps and motors supplies cooling water to the Category I requirements and Quality may be designed to non-seismic that the reactor coolant pumps Group 0 if it can be demonstrated cooling water for at least 30
will operate without component or the need for operator pro- minutes without loss of function safety grade instrumentation tective action. In addition, to detect the loss of including alarms should be provided reactor coolant pumps and component cooling water to the in the control room. The motors, and to notify the operator including audible and visual alarms, entire instrumentation system, of IEEE Std 279-1971.
should meet the requirements motors the reactor coolant pumps and If it is not demonstrated that without loss of function or operator will operate at least 30 minutes of the CCW system must meet the protective action, then the design following requirements:
for consistent with the criteria
1. Safety grade instrumentation shall be provided to initiate the reactor protection systemplant. For this case, the automatic protection of the to the seals and pump and component cooling water supply to non-seismic category I require- motor bearings may be designed ments and Quality Group 0; or supply to the pumps and motorsor
2. The component cooling water a single active failure shall be capable of withstanding as defined in our Branch a moderate energy line crack and be designed to seismic Technical Position APCSB 3-1 ASME Section 1II, Class 3 Category I, Quality Group 0 and requirements.
scope and motors are within the NSSS
The reactor coolant (RC) pumpsorder to demonstrate that an RC pump of design. Therefore, in least can operate with loss of component cooling water for ataction, design or the need for operator
30 minutes without loss of function the following must be provided:
of A detailed description of the events following the loss demon-
1. RC pumps and an analysis component cooling water to the important to safety may result strating that no consequencesdiscussion of the effect that the from this event. Include a coolers has on the RC pump loss of cooling water to the seal cooling water does not result seals. Show that the loss of in a LOCA due to seal failure.
ENCLOSURE 4 (CONT)
-18-
2. A detailed analysis to show that loss of cooling water to the RC pumps and motors will not cause a loss of the flow coastdown characteristics or cause seizure of the pumps, assuming no administrative action is taken. The response should include a detailed description of the calculation procedure including:
a. The equations used.
b. The parameters used in the equations, such as the design parameters for the motor bearings, motor, pump and any other equipment entering into the calculations, and material property values for the oil and metal parts.
c. A discussion of the effects of possible variations in part dimensions and material properties, such as bearing clearance tolerances and misalignment.
d. A description of the cooling and lubricating systems (with appropriate figures) associated with the RC pump and motor and their design criteria and standards.
e. Information to verify the applicability of the equations and material properties chosen for the analysis (i.e.,
references should be listed, and if empirical relations are used, provide a comparison of their range of appli- cation to the range used in the analysis).
Should an analysis be provided to demonstrate that loss of component cooling water to the RC pumps and motor assembly is acceptable, we will require certain modifications to the plant Technical Specifications and an RC pump test conducted under operating condtions and with component cooling water terminated for a specified period of time to verify the analysis.
C.18 WATER HAMMER IN STEAM GENERATORS WITH TOP FEEDRING DESIGN
Events such as damage to the feedwater system piping at Indian Point Unit No. 2, November 13, 1973, and at other plants, could originate as a consequence of uncovering of the feedwater sparger in the steam generator or uncovering of the steam generator feedwater inlet nozzles. Subsequent events may in turn lead to-the generation of a pressure wave that is propagated through the pipes and could result in unacceptable damage.
ENCLOSURE 4 (CONT)
-19- For CP/PDA and OL/FDA applications, provide the following for steam generators utilizing top feed:
1. erevent or delay water draining from the feedring following a drop in steam generator water level by means such as J-Tubes;
2. Minimize the volume of feedwater piping external to the steam generator whch could pocket steam using the shortest possible (less than seven feet) horizontal run of inlet piping to the steam generator feedring; and
3. Perform tests acceptable to the staff to verify that unacceptable feed- water hammer will not occur using the plant operating procedures for normal and emergency restoration of steam generator water level following loss of normal feedwater and possible draining of the feedring. Provide the procedures for these tests for staff approval before conducting the tests.
Furthermore, we request that the following be provided:
a. Describe normal operating occurrences of transients that could cause the water level in the steam generator to drop below the sparger or nozzles to cause uncovering and allow steam to enter the sparger and feedwater piping.
b. Describe your criteria or show by isometric diagrams, the routing of the feedwater piping from the steam generators outwards to beyond the containment structure up to the outer isolation valve and restraint.
c. Describe any analysis on the piping system including any forcing functions that will be performed or the results of test programs to verify that,either uncovering of feedwater lines could not occur or that, if it did occur, unacceptable damage such as the experience at the Indian Point Unit No. 2 facility would not result with your design.
ENCLOSURE 4 (CONT)
I
-20-
C.19 ENVIRONMENTAL CONTROL SYSTEMS FOR SAFETY RELATED EQtJIPMENT
Most plant areas that contain safety related equipment depend on the continuous operation of environmental control systems to maintain the environment in those areas within the range of environmental qualification of the safety related equipment installed in those areas. It appears that there are no requirements for maintaining these environmental control systems in operation while the plant is shutdown or in hot standby conditions. During periods when these environmental control systems are shutdown, the safety related equipment could be exposed to environmental conditions for which it has not been qualified. Therefore, the safety related equipment should be qualified to the extreme environmental conditions that could occur when the control equipment is shutdown or these environmental control systems should operate continuously to maintain the environmental conditions within the qualification limits of the safety related equipment. In the second case an environmental monitoring system that will alarm when the environmental conditions exceed those for which safety related equipment is qualified shall be provided. This environmental monitoring system shall (1) be of high quality, (2) be periodically tested and calibrated to verify its continued functioning, (3) be energized from continuous power sourcest and (4) provide a continuous record of the environmental parameters during the time the environmental conditions exceed the normal limits.
ENCLOSURE 4 (CONT)