ML13322A310
| ML13322A310 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear, Waterford, San Onofre, 05000000 |
| Issue date: | 03/03/1989 |
| From: | Poslusny C Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8903160428 | |
| Download: ML13322A310 (28) | |
Text
~pi REGUZ 0
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. 0. C. 20555 March 3, 1989 Docket Nos. 50-382, 50-368, 50-361 and 50-362 LICENSEES:
Arkansds Power & Light Company Louisiana Power & Light Company Southern California Edison Company FACILITIES:
Arkansas Nuclear One, Unit 2 Waterford 3 San Onofre, Units 2 and 3
SUBJECT:
SUMMARY
OF MEETING HELD ON FEBRUARY 27, 1989 WITH THE COMBUSTION ENGINEERING OWNERS GROUP TO DISCUSS SAFETY IMPLICATIONS OF IMPLEMENTING AN AUXILIARY MITIGATING SYSTEM ACTUATION CIRCUITRY (AMSAC)
IN ACCORDANCE WITH THE ATWS RULE On February 27, 1989, in Rockville, Maryland a meeting was held between NRR and the Combustion Engineering Owners Group CEOG) to discuss the safety implications of implementing a fully diverse Auxiliary Mitigating System Actuation Circuitry (AMSAC) for initiation of emergency/auxiliary feedwater system (AFS) as specified in the ATWS Rule.
The NRR staff reiterated the importance of meeting the requirements of the ATWS Rule and the immediate need to resolve the (AMSAC) implementation issue for ANO-2, SONGS-2, 3, and for Waterford 3. The CEOG presented its discussion of the functional requirements of the existing auxiliary feedwater actuation system (AFAS),
an overview of the AFAS design, and the safety implications of installing a diverse and independent AMSAC at these CE plants. Enclosure 1 is a copy of the presentation slides.
The CEOG emphasized that adding a non-safety grade AMSAC would degrade the reliability of the existing AFAS. The diverse actuation system would create the potential for generating conflicting signals to the ruptured steam generator, an unacceptable condition given a design basis event. According to the owners group, the potential for such a condition can only be eliminated by upgrading the diverse AMSAC to a level which would be as complex and as expensive as the existing actuation system.
In response, the NRR staff questioned the bases for the CEOG safety concern and indicated that the CEOG has not discussed or considered other potentially acceptable options for meeting the intent of the ATWS Rule's requirement for an AMSAC and still provide protection for design basis events. It was suggested that the CEOG seriously consider additional design options beyond those included in the recent exemption requests. One such option would be to design a non-safety grade AMSAC with diverse sensors (such as using high reactor pressure) as the initiation signal. The AMSAC signal will be overridden by the safety AFAS signal in the event of a design basis event such as a steam generator rupture.
This CEOG effort to consider additional options should parallel detailed discussions and meetings with NRR staff to result in the Owners Group development of a conceptual design of a diverse AMSAC. Information on such a design should 89C03s 160428 8A:30l3 PDR ADO(JCK 050
- 3 1
-2 be provided to the staff expeditiously in a formal submittal with sufficient details to precipitate an NRR decision on the AMSAC implementation and exemption issues for CE plants. The CEOG staff agreed to these suggested actions.
Finally, the NRR staff discussed an option for SCECO and LP&L to withdraw their exemption requests by March 2, 1989. Also, the licensee representatives were reminded of the ATWS Rule scheduler requirements for implementation by the third refueling outage after the July, 1984 date and that extensions must be officially requested and approved to avoid violation of the Rule. is a list of the attendees.
El5o Chester Poslusny, Project Manager Project Directorate - IV Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear Reactor Regulation
Enclosures:
As stated cc w/enclosures:
See next page D TRIBUTION cket File NRC PDR Local PDR PD4 Reading J. Calvo CPoslusny SNewberry G. Holahan G. Knighton J. Hannon D. Crutchfield OGC-Rockville E. Jordan B. Grimes ACRS (10)
T. Martin (Region IV)
PD4 Plant File
- SEE PREVIOUS CONCURRENCES:
PD4/PM*
SICB*
PD4/D CPoslusny:sr SNewberry JCalvo 03/01/89 03/02/89 03/:3 /89
be provided to the staff expeditiously in a formal submittal with sufficient details to precipitate an NRR decision on the AMSAC implementation and exemption issues for CE plants. The CEOG staff agreed to these suggested actions.
Finally, the NRR staff discussed an option for SCECO and LP&L to withdraw their exemption requests by March 2, 1989. Also, the licensEe representatives were reminded of the ATWS Rule scheduler requirements for implementdtion by the third refueling outage after the July, 1984 date and that extensions must be officially requested and approved to avoid violation of the Rule. is a list of the attendees.
Chester Poslusny, Project Manager Project Directorate - IV Division of Reactor Projects -
- III, IV, V and Special Projects Office of Nuclear Reactor Regulation
Enclosures:
As stated cc w/enclosures:
See next page DISTRIBUTION Docket File NRC PDR Local PDR PD4 Reading J. Calvo CPoslusny SNewberry G. Holahan G. Knighton J. Hannon D. Crutchfield OGC-Rockville E. Jordan B. Grimes ACRS (10)
T. Martin (Region IV)
PD4 Plant File
- SEE PREVIOUS CONCURRENCES:
PD4/PM*
SICB*
PD4/D CPoslusny:sr SNewberry JCalvo 03/01/89 03/02/89 03/3 /89
Nr. T. Gene Campbell Arkansas Power & Light Company Arkansas Nuclear One, Unit 2 cc:
Mr. Dan R. Howard, Manager Mr. Charles B. Brinkman, Manager Licensing Washington Nuclear Operations Arkansas Nuclear Cne Combustion Engineering, Inc.
P. 0. Box 608 12300 Twinbruuk Parkway, Suite 330 Russel1ville, Arkansas 728C1 ROLkville, Paryland 20852 Mr. James M. LevinL, Executive Director Site Nuclear Operations Honordble Wiliam Abernathy Arkansas Nuclear One County v of Pcpc County P. 0. Box 608 Pope County Courthouse Russellville, Arkansas 72801 Rubst.Hville, Arkansas 72801 Mr. Nicholas S. Reynolas Bishop, Cook, Percell & Reynolds 1400 L Street, N.W.
Washington, D.C. 20005-3502 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Office of Executive Director for Operations 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Senior Resident Inspector U.S. Nuclear Regulatory Commission 1 Nuclear Plant Road Russellville, Arkansas 72801 Ms. Greta Dicus, Director Division of Environmental Health Protection Arkansas Department of Health 4815 West Markam Street Little Rock, Arkansas 72201 Mr. Robert B. Bursum Babcock & Wilcox Nuclear Power Generation Division 1700 Rockville Pike, Suite 525 Rockville, Maryland 20852
Mr. Jerruld G. Deweast Waterfor 3 Lcuisiana Power & Light Company cc:
W. Malcolm Stevenson, Esq.
Pegiotal Administrator, Region IV Monroe & Leman U.S. Nuclear Regulatory Comrissicr 1432 Whitney Building Office of Executive Director for New Orleans, Louisiana 701C3 Operations 611 Ryan Plaza Drive, Suite 1000 Mr. E. Blake Arlington, Texas 76011 Shaw, Pittman, Potts & Trowbridge 2300 N Street, NW Mr. William H. Spell, Administrator Washington, D.C. 20037 Nuclear Energy Division Office of Environmental Affairs Resident Inspectcr/WAterford NPS Post Office Box 14690 Post Office Box 822 Baton Rouge, Louisiana 7C898 Killona, Lcuisiana 70066 Mr. Ralph T. Lally President, Police Jury Manager of Quality Assurance St. Charles Parish Middle South Services, Inc.
Hahnville, Louisiana 70057 Post Office Box 610CO New Orleans, Louisiana 70161 Chairman William A. Cross Louisiana Public Service Commission Bethesda Licensing Office One American Place, Suite 1630 3 Metro Center Baton Rouge, Louisiana 70825-1697 Suite 610 Bethesda, Maryland 20814 Mr. R. F. Burski Nuclear Safety and Regulatory Affairs Manager Louisiana Power & Light Company 317 Baronne Street New Orleans, Louisiana 70112
Mr. Kenneth P. Baskin San Onofre Nuclear Generatiing Southern California Edison Company Station, Units 2 aria 3 cc:
Mr. Gary D. Cotton Mr. Hans Kaspar, Executive Director Senior Vice President Marine Review Committee, Inc.
Engineering and Operatious 531 Encinitas Boulevard, Suite 105 San Diego Gas & Electric Company Encinitas, Californid 92024 101 Ash Street Post Office Box 1831 San Diego, California 92112 Mr. Mark Medford Southern California Edison Company Charles R. Kocher, Esq.
2244 Walnut Grove Avenue James A. Beoletto, Esq.
P. 0. Box 800 Southern California Edison Company Rosemead, California 91770 2244 Walnut Grove Avenue P. C. Box 800 Mr. Robert G. Lacy Roserread,. California 91770 Manager, Nuclear Department San Diego Gas & Electric Company Orrick, Herrington & Sutcliffe P. 0. Box 1831 ATTN:
David R. Pigott, Esq.
San Diego, California 92112 600 Montgomery Street San Francisco, California 94111 Richard J. Wharton, Esc.
University of San Diego School of Alan R. Watts, Esq.
Law Rourke & Woodruff Environmental Law Clinic 701 S. Parker St. No. 7000 San Diego, California 92110 Orange, California 92668-4702 Charles E. McClung, Jr., Esq.
Attorney at Law Mr. S. McClusky 24012 Calle de la Plaza/Suite 330 Bechtel Power Corporation Laguna Hills, California 92653 P. 0. Box 60860, Terminal Annex Los Angeles, California 90060 Regional Administrator, Region V U.S. Nuclear Regulatory Commission Mr. Charles B. Brinkman 1450 Maria Lane/Suite 210 Combustion Engineering, Inc.
Walnut Creek, California 94596 12300 Twin Brook Parkway, Suite 330 Rockville, Maryland 20852 Resident Inspector, San Onofre NPS c/o U. S. Nuclear Regulatory Commission Mr. Dennis F. Kirsh Post Office Box 4329 U.S. Nuclear Regulatory Commission Sdn Clemente, California 92672 Region V 1450 Maria Lane, Suite 210 Wdlriut Creek, California 94596 Mr. Sherwin Harris Resource Project Manager Public Utilities Department City of Riverside City Hall 3900 Main Street Riverside,.-California 92522
Enclosure C-E OWNERS GROUP (AP&L, LP&L, SCE)
PRESENTATION TO NRC ON THE SAFETY IMPLICATIONS OF INSTALLING A DIVERSE AUXILIARY FEEDWATER ACTUATION SIGNAL IN COMPLIANCE WITH 10CFR50.62 (THE ATIS RULE)
FEBRUARY 27, 1989
PURPOSE REVIEW THE SAFETY IMPLICATIONS OF IMPLEMENTING A FULLY DIVERSE EMERGENCY AUXILIARY FEEDWATER ACTUATION SYSTEM IN ACCORDANCE WITH THE AT14S RULE
BACKGROUND 0
NUMEROUS NRC/CEOG MEETINGS AND CORRESPONDENCE BETWEEN MARCH, 1985 AND JANUARY, 1988 0
APPEARED TO HAVE REACHED AGREEMENT SEVERAL TIMES 0
PERSONNEL CHANGES ADDED TO RESOLUTION DIFFICULTIES 0
INTERACTION CULMINATED IN JANUARY 11, 1988 NRC LETTER PROVIDING EXEMPTION GUIDANCE 0
SAFETY CONCERNS WITH DIVERSE EFAS ARE FUNDAMENTAL TO EXEMPTION REQUEST
PRESENTATION OUTLINE 0
FUNCTIONAL REQUIREMENTS OF EXISTING AUXILIARY FEEDWATER ACTUATION SYSTEM 0
OVERVIEW OF HARDWARE DESIGN 0
SAFETY IMPLICATIONS OF DIVERSE AUXILIARY FEEDWATER ACTION SYSTEM
FUNCTIONAL REQUIREMENTS OF EXISTING AFAS 0
DESIGN BASIS OF SYSTEM 0
EVENTS REQUIRING EFAS
DESIGN BASIS OF AFAS SYSTEM 0
INDEPENDENT MEANS OF MAINTAINING SECONDARY INVENTORY 0
SUFFICIENT INVENTORY RESERVE FOR ORDERLY PLANT COOLDOWN FOR DURATION OF DBE 0
IDENTIFY SG WITH PRESSURE BOUNDARY RUPTURE OVERCOOLING CONTAINMENT PRESSURE 0
ISOLATION OF SG WITH PRESSURE BOUNDARY RUPTURE OVERCOOLING CONTAINMENT PRESSURE 0
CONTROL WATER LEVEL IN INTACT SG FOLLOWING SECONDARY PRESSURE BOUNDARY RUPTURE OVERCOOLING
FUNCTIONAL REQUIREMENTS OF AFAS 0
DETERMINES THAT MAIN FEEDWATER SYSTEM FLOW IS INSUFFICIENT BASED ON LOW STEAM GENERATOR LEVEL 0
IDENTIFIES THAT STEAM GENERATOR PRESSURE BOUNDARY IS RUPTURED (LOW STEAM GENERATOR PRESSURE OR DP BETWEEN STEAM GENERATORS) 0 STARTS AUXILIARY FEEDWATER PUMPS 0
OPENS AND CLOSES VALVES TO PROVIDE A FLOWPATH TO INTACT STEAM GENERATOR 0
INTERACTION WITH MAIN STEAM ISOLATION SIGNAL ON A COMPONENT LEVEL
DESIGN BASIS EVENTS REQUIRING AFAS 0
STEAM LINE BREAK 0
FEEDWATER LINE BREAK 0
EVENTS WITH MAIN STEAM ISOLATION
OVERVIEW OF HARDWARE DESIGN 0
PLANT PROTECTION SYSTEM CONTAINS CIRCUITRY AND EQUIPMENT FOR REACTOR TRIP AND ENGINEERED SAFETY FEATURES ACTUATION SIGNAL (ESFAS) 0 ESFAS CIRCUITRY CONSISTS OF:
BISTABLES MATRIX LOGIC MATRIX RELAYS TRIP PATH CIRCUIT FINAL ACTUATION LOGIC
BISTABLES RECEIVE ANALOG SIGNALS FROM PROCESS MEASUREMENT LOOPS COMPARISON OF INPUT SIGNALS TO FIXED OR VARIABLE SETPOINTS BISTABLE OUTPUT CHANGES FROM HIGH TO LOW CONDITION DEENERGIZES ASSOCIATED BISTABLE TRIP RELAYS
MATRIX LOGIC BISTABLE TRIP CHARACTERIZED BY DEENERGIZING THREE ASSOCIATED BISTABLE TRIP RELAYS FOUR SETS OF THREE TRIP RELAYS IN FOUR PROTECTION CHANNELS SIX LOGIC "ANDS" LOGIC "ANDS" CONNECTED IN SERIES WITH TWO SETS OF TWO PARALLEL MATRIX RELAYS INDIVIDUAL DC POWER SUPPLIES FORMED INTO A LOGIC MATRIX SIX SIMILAR LOGIC MATRICES PROVIDED FOR EACH ESFAS
TRIP PATH CIRCUIT TRIP PATH CIRCUIT FOR EACH PROTECTIVE FUNCTION FORMED BY CONNECTING SIX CONTACTS IN SERIES CONTROLS POWER INTERRUPTION TO INITIATION RELAYS
FINAL ACTUATION LOGIC MAKES USE OF INITIATION RELAY OUTPUTS OF THE PPS EACH ESFAS HAS TWO SEPARATE INITIATION RELAYS OUTPUTS OF INITIATION RELAYS GO TO REDUNDANT ACTUATION TRAINS TWO-OUT-OF-FOUR LOGIC DEENERGIZES PUMP AND VALVE GROUP ACTUATION RELAYS CONTACTS FOR USE IN CONTROL SYSTEMS FOR ACTUATED EQUIPMENT
SAFETY IMPLICATIONS OF DIVERSE AUX, FEEDWATER ACTUATION 0
DIVERSE AFAS DESIGN MUST ENSURE EXISTING AFAS SAFETY FUNCTIONS ARE PRESERVED 0
SAFETY CONCERNS DRIVE COMPLEXITY OF DIVERSE AFAS DESIGN 0
HOW WILL A DIVERSE AFAS HANDLE A STEAM /
FEED LINE BREAK?
SAFETY IMPLICATIONS OF DIVERSE AUX, FEEDWATER ACTUATION 0
STEAM LINE BREAK / EXCESS HEAT REMOVAL SCENARIO 0
EFW FLOW TO A RUPTURED STEAM GENERATOR COULD:
INCREASE RATE OF HEAT REMOVAL BY FEEDING BROKEN GENERATOR DIVERT EFW AWAY FROM INTACT GENERATOR FOR THE LONG TERM COOLDOWN EFW TO BROKEN GENERATOR CAUSES FURTHER INCREASE IN CONTAINMENT PRESSURE 0
CONDITIONS INDICATIVE OF AN ATWS ARE ALSO INDICATIVE OF SOME SECONDARY SYSTEM PIPE BREAKS 0
DIVERSE AFAS MUST INCLUDE LOGIC TO LOCK OUT EFW FLOW TO THE RUPTURED STEAM GENERATOR
SAFETY IMPLICATIONS OF DIVERSE AUX. FEEDWATER ACTUATION 0
DESIGN OPTION 1 - EQUAL WEIGHT TO BOTH SIGNALS CONTRADICTORY SIGNALS GIVE NO BASIS FOR PREDICTING ACTUAL VALVE POSITION DETRIMENTAL TO PLANT SAFETY 0
DESIGN OPTION 2/3 - GIVE PREFERENCE TO ONE AFAS CONTROL GRADE PREFERENCE - EQUIVALENT TO REPLACING SAFETY GRADE AFAS WITH NON-SAFETY GRADE SYSTEM SAFETY GRADE PREFERENCE - DEFEATS THE PURPOSE OF INSTALLING A DIVERSE AFAS
SAFETY IMPLICATIONS OF DIVERSE AUX, FEEDWATER ACTUATION 0
DESIGN OPTION 4 - ADDITIONAL LOGIC TO CHOOSE BETWEEN VALID AND FAULTY SIGNALS MUST BE SAFETY GRADE WOULD HAVE TO MONITOR SG LEVEL AND DIFFERENTIAL PRESSURE MUST BE AS RELIABLE AS EXISTING AFAS THEREFORE 3 OR FOUR CHANNELS CONCLUSION - EXISTING AFAS WOULD HAVE TO BE DUPLICATED
SAFETY IMPLICATIONS OF DIVERSE AUX. FEEDWATER ACTUATION 0
DESIGN NOW INVOLVES A SECOND SAFETY-GRADE AFAS 0
ATWS RULE ASSUMES THAT A COf"iON MODE FAILURE DISABLING A REDUNDANT SAFETY SYSTEM IS CREDIBLE 0
BACK TO CHOICE BETWlEEN CONFLICTING SIGNALS
SAFETY IMPLICATIONS OF DIVERSE AUX, FEEDWATER ACTUATION 0
OTHER CONSIDERATIONS MSIS / EFAS INTERACTION ON COMPONENT LEVEL MUST BE PRESERVED COMPLICATED SYSTEMS INTERACTIONS MAY BE INTRODUCED THAT ARE DIFFICULT OR IMPOSSIBLE TO ANALYZE IMPLEMENTING A COMPLEX DIVERSE SYSTEM INCREASES THE PROBABILITY OF HUMAN ERROR
CONCLUSIONS 0
A PROVEN / RELIABLE EFAS EXISTS IN THE PLANTS TODAY 0
INSTALLATION OF A DIVERSE AFAS MAY INCREASE THE SEVERITY OF CERTAIN EVENTS UNLESS ALL SAFETY CONCERNS ARE ADDRESSED 0
THE COST OF INSTALLING A DIVERSE EFAS IS NOT JUSTIFIED BY THE RESULTING ATWS RISK REDUCTION
CONCLUSIONS 0
EXEMPTION REQUEST BASED ON:
SAFETY CONCERNS PRESENTED IN EXEMPTION REQUEST CLARIFIED TODAY BENEFIT OF MODIFICATION (RISK REDUCTION)
PRESENTED IN EXEMPTION REQUEST COST OF MODIFICATION PRESENTED IN EXEMPTION REQUEST UNFAVORABLE VALUE IMPACT RATIO CEOG/NRR ATWS MEETING FEBRUARY 27, 1989 ROCKVILLE, MARYLAND Nuclear Regulatory Commission Combustion Engineering S. Long C. Brinkman J. Monninger J. Kapinos J. Calvo D. Yanosy H. Li J. Pfeifer V. Thomas M. Ryan D. Wigginton E. Brown A. Thadani S. Newberry EG&G W. Hodges C. Poslusny A. Nolan C. C. Harbuck C. Trammell NUS M. D. Lynch M. Cheok Arkansas Power & Light R. Bryan R. Barnes M. Tull V. Bond Southern California Edison D. Mercurid J. Rainsberry D. Evans Louisiana Power & Light D. Gamble R. Prados