ML19331A783
| ML19331A783 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 12/18/1972 |
| From: | Seiss C Advisory Committee on Reactor Safeguards |
| To: | Schlesinger J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19331A778 | List: |
| References | |
| NUDOCS 8007230813 | |
| Download: ML19331A783 (7) | |
Text
O
.L ADVISORY COMMITTEE ON REACTOR SAFEGUARDS UNITED STATES ATOMIC ENERGY COMMISSION WASHINGTON. D.C.
20545 i
December 18, 1972 g,
330
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Honorable Ja=es R. Schlesinger Chairman U. S. Atomic Energy Co= mission Washington, D. C.
20545
Subject:
STATUS OF GENERIC ITEMS RELATING TO LIGHT-WATER REACTORS
Dear Dr. Schlesinger:
The Advisory Committee on Reactor Safeguards and't'he Regulatory Staff have identified a number of safety problems during I.ecent years that are coc=on to a specific type of light-water reactor or to all light-water reactors (LWRs). The " generic items"
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discussed herein have been cited in Committee reports pertaining-to the construction or operation of LWRs; additional ;;cneric items not cited in the report have been identified by the Directorate of Licensing. The ACRS customarily has used a general paragraph to cover those generic items noted in its previous reports. This paragraph reads:
"Other problems relating to large water reactors, which have been identified by the Regulatory Staff and the ACRS and cited in previous reports, should be dealt with appropriately by the Rc;;ulatory Staff and the applicant as suitable approachen arc developed". The use of such a paragraph has permitted the ACRS to emphasize either new or particularly significant generic probic=s without listing in detail those problems cited in the past.
The Committee believes that many of the generic items cited in its reports have been resolved by actions of the applicants or decir. ions of the Regulatory Staff, in cooperation with the ACRS.
Resolution of the remaining items are pending.
The'Coemittee defines " resolved" to scan that a specific conclusion or policy decision bas been reached by the Directorate of Licensing and the ACRS. Resolution of an item indicates that a the Committee is satisfied in a gencric sense; however, this does not mean that improvements should not be investigated and,
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Honorable James R. Schlesinger December 18, 1972 posulbly, impicmented.
In fact, requirements may dif f er for specific plants because of such factors as site characteristics and construction authoriaation dates, especially as they apply to backfit requirements.
Group I of the attach =cnt includes gencric problems that have been resolved together with the specific action that resulted in the resolution. Group II includes those items for which resolution on a generic basis is still pending.
The ACRS and the Regulatory Staff will continue to consider Group II items and their significance to safety on a case-by-car.e bar,1c until generic resolution is reached.
Formal actions, such as issuance of Regulations or Safety Guides, are anticipated for many of the Group II itccs.
The ACRS expects to report to you from time to time tm the
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status of generic items.
Sincerely yours,
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C. P. Sicss Chairman
Attachment:
Gencric Items
So - 321,sth)
GENERIC ITEMS Croup I - Resolved Cencric Items 1.
Net Positive Suction Head for ECCS Pumps:
Covered by Safety Guide 1 2.
Emergency Power:
Covered by Safety Guides 6 and 9 and portions of IEEE-308 (1971) 3.
Hydrogen Control Af ter a Loss-of-Coolant Accident (LOCA):
Covered by Safety Guide 7 and Supplement i
4.
Instrument Lines Penetrating Containment:
Covered by Safety Guide 11 and Supplement S
5.
Strong Motion Seismic Instrumentation:
Covered by Safety Guide 12 6.
Fuel Pool Design Bases:
dAND Covered by Safety Guide 13 7.
Protection of Primary System and Engineered Safety Features Against Pump Flywheel Missiles:
Covered by Safety Guide 14 8.
Protection Against Industrial Sabotage:
Covered by Safety Guide 17 9.
Vibration Monitoring of Reactor Internals and Primary System:
Covered by Safety Guide 20 10.
Inservice Inspection of Reactor Coolant Pressure Boundary:
Covered by ASME Boiler and Pressure Vessel (BPV) Code,Section XI 11.
Quality Assurance During Design, Construction, and Operation:
Covered by 10 CFR 50, Appendix B; ASME BPV Code,Section III; ANSI N-45.2-1971; Safety Guide 28; and Proposed Standard A::S-3.2 12.
Inspection of BWR Steam Lines Beyond Isolation Valves:
Covered by ASME BPV Code,Section XI 13.
Independent Check of Primary System Stress Analysis:
Covered by ASME BPV Code,Section III 14 Operational Stability of Jet Pumps:
Tests and operating experience at Dresden 2 and 3 and other jet pump BURS have -satisfied the ACRS concerns for this generation plant.
Generic Items Group I (Cont'd)'
15.
Pressure Vessel Surveillance of Fluence and NDT Shif t:
Covered by 10 CFR 50, Appendix A and proposed Appendix 11; and ASTM Standard E-185-70 16.
Nil Ductility Properties of Pressure Vessel Paterials:
Coverec by 'O CFR $0, Aodendix A and proposed Appendix G; and AS:E 3Pk Code,Section III 17.
Operation of Reactor With Less Than All Loops In Service:
Covered by ACRS-Regulatory Staff position that manual resetting of several set points on the control room instruments under specific conditions and procedures is acccptable in taking one primary loop out of service.
This position is based on the expectation that this code of operation will be infrequent.
18.
Criteria for Prcoperational Testing:
Covered by Operational Guide for the Planning _of Initial Startup Programs, December 7, 1970 19.
Diesel Fuel Capacity:
Covered by ACRS-Kogulatory Staff position requiring 7 days fuct 20.
Capability of Biological Shield Withstanding Doubic-Ended Pipe Break at Safe Ends:
Covered by ACRS-Regulatory Staf f position cited in several letters that such a failure should have no unacceptable consequences. ACRS-Regulatory Staff position document will be prepared.
l 21.
Operating One Plant While Other(s) is/ arc Under Construction':
Specific requirements have been established by ACRS-Regulatory Staff.
Position will be prepared.
l l
22.
Scismic Design of Steam Lines:
Covered by Safety Guide 29 23.
Quality Group Classifications for Pressure Retaining Components:
Covered by Safety Guide 26 24 Ultimate Heat Sink:
Covered by Safety Guide 27 25.
Instrumentation to Detect Stresses in Containment Walls:
Covered by Safety Guide 18
Cencric Items Croup II - Pesolution Pending 1.
Adequacy of Primary System Leak Detection and Location:
{
t ACRS-Regulatory Staff position requires systems in addition to cump ceacurc=cnts.
2.
Positive Modcrator Coefficient:
One solution is use of fixed burnable poison in core.
3.
Use of Sensitized Stainless Steel:
ACRS-Regulatory Staff position is to minimize use. *
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i 4.
Protection Against Pipe Whip:
l Ultimate decision will depend on revicw of available -information l
on pipe break probabilitics.
- l 5.
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Turbine failures for past 16 years have been evaluated and a i
statistical probability analysis has been completed.
6.
Fixed In-Core Detectors on High Powcr PWRs:
Some information is available.
7.
Performance of Critical Components (pumps, cabics, etc.) in Post-LDCA Environment:
Substantial information available in topical reports.
Evalua-tion is required to determine if all necessary information is on hand.
- 8.
Effective Operation of Containment Sprays in a LOCA:
Extensive dacumentation in topical reports.
Review and evaluation are required.
9.
Relief Valves Controlling Bypass Paths on BWR Pressure Suppression Containments:
Analyscs made in topical reports.
Evaluation required by ACRS-Reguintory Staff.
- A Safety Guide is in preparation.
Ceneric Items Group II (Cont'd).
10.
Anticipated Transients '41thout Scram:
Data provided by applicants.
Evaluation is required to permit a decioion to cover BWRs and PWRs operating and under constructio'n.
11.
Radwaste Management:
10 CFR 50, Appendix I, covers in part:
Formal ruicmaking decision required to implement fully.
12.
Possible Failure of Pressure Vessel Post-LOCA by Thermal Shock:
Safety Guide 2 covers current in fo rmat ion.
Ultirate position as to significance of thermal shock requires input o f f rac,ture mechanica data on irradiated steels from the !!eavy Section Steel Technology Program.
13.
Instruments to Detect Fuel Failures:
Instrumentation exists to deccct fuel failures:
ACRS-Regulatory Staff believes progress is satisfactory; however, continuing wore is required.
14 Monitoring for Excessive Vibration or Loose Parts Inside the Pressure Vessel:
State-of-the-Art results appear promising.
More work may be required prior to decision as to installation of equipment.
- 15. Connon Mode Failures:
Requirements for diverse components should be established.
- 16. Emergency Core Cuoling System Capability:
Need for improvement cited by Regulatory Staff and stated in ACRS report of January 7,1972.
Further studies and evalua-tions are in progress.
17.
Behavior of Reactor Fuel Under Abnormal Conditions:
This includes:
flow blockage; partial = citing of fuct assemblics as it affcets reactor safety; and tcansicnt et'isets on fuci integrity. The PBF program will address some of tuese items.
Concric Items !
Croup II (Cont'd)
- 18. Emergency Power for Two or More Reactors at the Scme Site:
Additicnal work is tequired on protcetion. systems for multiple units.
19.
! bin Steam Isolation Valve Leakage of EWRs:
A definitive position is required of ACKS-Regulatery Staff in the light of continuing experience.
20.
Instrumentation to Follow the Course of an Accident:
Soce equipment exists; further analyses are required to establish equipment requirements.
21.
BWR Recirculation Pump Overspeed During LOCA:
Topical reports preparad.
Decision required by ACRS-
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Regulatory Staf f.
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22.
The Advisability of Seismic Scram:
Further studies required to establish need.
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