ML19309G841
| ML19309G841 | |
| Person / Time | |
|---|---|
| Issue date: | 04/04/1980 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-1702, NUDOCS 8005070672 | |
| Download: ML19309G841 (25) | |
Text
{{#Wiki_filter:- _ _ _ _ _ _ _ m ' ' ' MINUTES OF THE ACRS SUBCOMMITTEE ON g,g p W POWER AND ELECTRICAL SYSTEMS 8005 DECEMBER 13, 1979 '~ ^ j .g WASHINGTON, D. C. 2@A g Y C Staff, The ACRS Subcommittee on Power and Electrical Systems met with the i l power, instru-g to discuss several miscellaneous items with regard to electr ca h l t A notice mentation, control, and protection systems in nuclear power p an s.1979 (Attach of the meeting appeared in the Federal Register on November 28, B). A copy of the detailed presentation schedule is attached (Attachmen h t C). A A list of attendees at the Subcommittee meeting is attached (Attac men A). hd list of documents provided to the Subcommittee for this meeting is attac The There were no public statements either written or oral. (Attachment D). entire meeting was open to members of the public. MEETING WITH THE NRC STAFF (OPEN SESSION) 1.0 Subcommittee Chairman's Opening Remarks ltants Dr. Kerr, Subcommittee Chairman, introduced the ACRS members and con 1.1 / He pointed of the Subcomnittee and noted the purpose of the meeting. ii of out that the meeting was being conducted in accordance with the prov s Sunshine Act and the Federal Advisory Committee Act and the Government in the l for the meeting. that Mr. Gary Quittschreiber was the designated Federal Emp oyee from Re stated that no requests for oral statements nor written statements i ting. members of the public had been received with regard to th s mee Control Systems Impact on Safety ft Mr. R. Satterfield, NRC Staff, discussed the following with regard to sa f 1.2 implications of control systems (Attachments 1 t t d to ensure they don't affect the capability e i in control systems be invest ga e limited to of the protection system; however, the past NRC reviews have been reviewing only interfaces. The RESAR 414 Integrated Protection System (IPS) review was ntrol system interaction. e NRC attempt at a systematic review of pro NUREG 0493 provided the guidelines for th THIS DOCUMENT CONTAINS F0IA EXEMPT 10f POOR QUALITY PAGES
. Dec 13, 1979 PES The Westinghouse IPS and the B&W ICS have extensive interconnections e between protection and control systems and would appear to be more vulnerable than other designs to adverse interaction, Quantitative reliability analyses have not been used by the NRC in the o past to determine the acceptability of nuclear plant control system designs. Control systems have normally been ignored from the safety standpoint e because of the rapid nature of the transients and the slow response of the control systems. The short and long term lessons learned task force recommendations require e that control system failures be studied in detail to determine their effects on safety. The f4RC does not perform detailed assessments of the affects of RPS inverter e failures on control systems. Control system failures can occur due to failures An 1&E Bulletin has been issued regarding this of many different power systems. matter. Problems exist with controlling steam generator feedwater in the automatic e mode at low flow rates. Individually, these have not been considered to be a safety problem; however, considering the frequency of challenges of the safety systems as a result of the challenges, the NRC Staff feels this needs further consideration. Mr. Tondi, NRC Staff, said he would furnish the Subcommittee with a copy of the which concluded that ORUL protection and control system interaction failure of the B&W ICS would not result in a condition for which one would not have adequate protection. Mr. Novak, NRC Staff, told the Subcommittee that prior to TMI-2 their concern for control system operation normally ended once the rods scrammed. Now, they are finding that the control system can alter the course of the accident by delaying the scram or making the transient worse so that the protection system is less effective. Dr. Hanauer, NRC Staff, noted that the scram system is used as a control system to shutdown the reactor for some transients; however, if you did not have this anticipatory trip the reactor temperature pressure or other parameter
D c 13, 1979 , PES ~ would trip the reactor as part of the protective system trips. Mr. Lpler suggested that attention be given to designing systems that can be tested without impairing its capability to perform its function, i.e., without Dr. Hanauer noted that taking the equipment out of commission during testing. this was being addressed as part of TMI Lessons Learned with regard to plant Automatic return-to-normal features are imposed in some status monitoring. cases but the !;RC Staff does not have a uniform requirement. Safety Implications of Control Systems and Plant Dynamics 1.3 Demitrius Basdekas, NRC Staff, discussed his concern that the performance of control systems could affect safety systems and suggested that all operating reactors be derated to 65% power until such time that a detailed plant-by-plant failure mode and effects analysis of the control systems and other non-safety He feels the flRC does not understand the influence of the systems is completed. control systems or plant behavior. Dr. Hanauer said that the NRC Staff has come to the opinion that control systems are important and is developing a program to factor the review of control and Hanauer noted that an non-safety systems into the licensing review process. important difference between the NRC Staff and Mr. Basdekas is the need to derate plants to 65% power during the review process. He suggested that if the ACRS has any comments with regard to the six plant IREP study, which will investi-gate systems interaction, that they make their suggestions known so they can be factored into the program. Mr. Tondi noted that controllers for control systems would usually tail by He felt that going into a manual mode which tends to stabilize the dynamics. dampening controllers would tend to slow the response such that they would not be able to respond adequately to plant transients. 1.4 Emertency Electrical Power Requirements Mr. Faust Rosa and Dominic Tondi, NRC Staff, discussed the following with regard to emergency electrical power systems (Attachments 9 through 12):
Dec 13, 1979 PES The fiRC Staff has proposed the following modifications in the o Arkansas Nuclear One emergency power system as a result of the September 16, 1978 degraded safety bus voltage problems: Installing second level undervoltage relays, two on each 480V Class 1. IE Bus with drop out setting at 92% (motor base voltage) and 8 second time delay in coincident trip logic (2-out-of-2) for degraded voltage protection. Blocking the 92% relay trips during start of reactor coolant pumps 2. A Class IE for 20 seconds by means of a Class IE blocking relay circuit. timer will be added to annunciate a delayed alarm in the control room in case the blocking circuit does not automatically reset. Deleting the slow automatic transfer from unit auxiliary transformer 3. to start-up transformer #1. Installing an additional inverse-time undervoltage relay on each 4. 4160V Class IE Bus with 78% (motor voltage base) drop out setting in parallel trip logic (1-out-of-2) for loss of off-site power protection. Blocking of the load shedding feature on the 4160V safety busses when 5. 90nerators are supplying these busses, provided a safety signal is the diesel present, and automatically reinstate the feature when onsite source supply breakers are tripped. Using the sequencer for starting the ESF loads on either source of 6. off-site power. Shedding selected non-essential plant loads when start-up transformer 7.
- 2 is the source of off-site power.
There is no dominant failure mode for inverters and inverters appear to e be no less reliable than other components in the electrical power supply distribution system. Problems exist with regard to getting utilities to respond to the NRC e Some requests for information needed to evaluate their electrical systems. utilities still owe NRC responses to the Millstone-2 degraded bus voltage event which occurred about two years prior. The NRC has also been lax in answering some of their partial responses. New plants to be licensed have a series of tests to verify proper e electrical system operation on loss of off-site power and full load rejection as required by Regulatory Guide 1.68. Most operating plants have different test requirements.
. Dec 13, 1979 PES The NRC Staff has not performed a vital AC power inverter system e reliabilit'y study. Possibly, the LER review group will become sensitive to the events which result in the greatest risk and will suggest criteria or guidance for upgrading systems or components offering the greatest challenge g to safety. No quantitative reliability requirements are specified by the NRC for e the off-site /on-site power interface. If failures occur during testing they are investigated, the cause is found and repaired, and the system is retested. Dr.-Kerr discussed the problem of deciding whether a system is acceptable where The there are no established acceptance criteria on which to base a decision. NRC Staff is optimistic that the LER review program will be helpful in developing acceptance criteria. Mr. Ebersole suggested that the NRC and/or industry look at all the loads on the vital bus which have bumpless transfers to see whether the loads really need the It was his opinion that requiring a bumpless source degrades bumpless source. reliability. Rosa said that is part of the new analysis to be done. Task Action Plan A-44 Regulatory Guide 1.81 no longer accepts shared diesels. (TAP A-44) on Station Blackout will address the overall acceptability of shared diesels. The NRC Staff does not want to make any statements on the acceptabi-lity of shared diesels until that study is completed; however, Rosa felt that unshared diesels do provide more overall reliability. TAP A-44 will also specify whether loss of all AC power should be a design basis accident. The Subcommittee discussed the need to perform an actual loss of all AC power test on new nuclear plants about to be licensed. Mr. Ebersole felt such a test should be performed at a very low power level. Dr. Kerr felt that the appli-cants would and should be very skeptic,al about performing such a test. Mr. Ebersole suggested that the NRC Staff look at the generation of missiles from the failure of connected loads due to high frequency caused by overspeed runaway of turbine' generators carrying house loads, caused by control system f failures.
Dec 13, 1979 PES ts Environmental Qualification Requirements for Critical Componenha Mr. Tondi noted that the Division of Operating ReactorsAlthoug 1.5 tems other than safety on equipment qualification. instructions to I&E, they are considering including sys lification. The systems to be added to the list of things requiring qua k that fall outside i Staff's attitude is changing and they are looking at th ngs the Safety Analysis Chapter 15 kind of accidents. H. Denton to TVA in response to questions from Dr. Kerr about a letter frombe designed s concerning Bellefonte, which requires that the plant i ed for 10 following an anticipated transient no operator action be requ rd to cope minutes and only safety grade equipment be neede t to meet the antici-V. Moore indicated that it has been a standing requiremenlly initiated safe i pated transient and accident limits with automat caSat tran-PGHR are not violated. equipment. sient out once it is demonstrated that the Dr.B and L thing then the Once it is demonstrated that the protective system does itsTond operator can take appropriate action. i t but they are not g ven action within the first 10 mb utes to protect equipmen credit for this in the analysis. is better to environ-The Subcommittee discussed the philosophy of whether itt environment mentally qualify equipment for a hostile accidenhostile environment and in the hostile environment or not to qualify it for aThe for that Lipinski discussed the problems associated with proving move it out. for maintenance and either method. k hermetic seals still exist after they have been bro en testing. i i of solid state Mr. Ebersole discussed the need for temperature mon tor ngmming so th safety system cabinets and the desira'bility of pre-progra before it became system would lock itself into a preferred mode of operationThe inoperable and went in the wrong direction.They feel it would not individual cabinet monitoring. tion that would the temperature detector in a cabinet at a selected loca
Dec 13, 1979 PES cover all possible overheating events that could occur and that redundancy and separation preclude the need for individual cabinet temperature monitoring. Dr. Kerr thanked the tiRC Staff and Subcommittee members for their participation. The meeting was adjourned at 4:00 pm.
- t For additional details, a complete transcript of the meeting is available in the Nuclear Regulatory Commission Public Docunent Room, 1717 H Street, N. W.
Washington, D. C. 20555, or from International Verbatim Reports, Inc., 20002. 499 South Capitol Street, S. W., Suite 107, Washington, D. C. 1 G e e v
- o. 230 / Wednesday, Novemb r 28. 1979 / Notices Feder:1 Register / Vol. 43, rgo, g.
Solicitation Cffica. Nztional dit:rmined that tha mating would fall tl usnes Rtfer' nes Service. Box within exrmptions (4) and (6) of 5 U.S.C. c:nsult nts, and St ff. Persons d; string (coffectiv e oc ville, Miryland 20850. 552b(c) and that it is essential to close to make oral statements should notify ' ePplicat this meeting to protect the free exchange the Designated Federal Employee as far amendmN.' Bratt.
- rector, Notional /nstitute oflow ofinternal views and to avoid in advance as practicable so that tentend criminalfustice.
interference with operation of the ' appropriate arrangements can be made Septembe[~ 11 of the asmos rued n-a-m e 4s eel Committee. to allow the necessary time during the .certain eff[.. if you desire more specific meeting for such statements. to Section.. es esse-se.es information, contact the Advisory De agenda for subject meeting shall exemptin 2(a)(35) Committee h!anagement Officer Mr. be as follows: ~ Itive Research Program of Stephen ]. McCleary,80615th Street Thursday, December 13,1979,8:30 a.m. 27 c (1). h on Crime Control; NW., Washington. D.C. 20506. or call Until the Conclusion of Business ACIto[ lon 202-724-0367. stiinalInstitute of Law Sterten I. McCleary, The Subcommittee may meet in te.' Executive Session, with any ofits Individua unt and Criminal Justice Advisory Committee Management Officer. consultants who may be present, to Variable [ii-annrunces a competitive tru ooc. m.ane4e rad n-a-a e es amt progr:m of Research on Crime explore and exchange their preliminary " Contra.h asumo coos tsa.ei-as A t:tzt of $850,000 has been opinions regarding matters which should contingera d. ! ts fund research on crime be considered dunng the meeting to ("Continm. ffects cssociated with the Humanities Advisory Panel; formulate a report and against thw[. . of th3 s:nctioning power of the Cancellation recommendations to the full Committee, the event nf iustice systIm. A total of six to At the conclusion of the Executive - trds cr2 anticipated from these Session, the Subcommittee will hear Interested pc November 23.1979. i Applicab.c.. This is to give notice that the meeting presentations by and hold discussions file with tLm ) peer review panel, consisting of of the Humanities Panel scheduled to be with representatives of the NRC Staff. of therepn 1 thy fiIld, will be employed to held on December 6-7,1979 at 80615th and their consultants, pertinent to thfs which are sur ommendations for funding. The sta fir rectipt of proposals is Street NW., Washington, D.C has been review. 380. canceled. Announcement of this meeting Further information regarding topios We VarLI - cf th2 solicitation can be appeared in the Federal Register on to be discussed, whether the meeting account of1 by writing to: November 20,1979. Vol. 44, page 66713, has been cancelled or rescheduled;the as a udt b.4 item No.1.The purpose of the meeting Chairman's ruling on requests for the custoh m.. . > licit: tion Office. National was to review applications in the opportunity to present oral statements Company... Justica Reference Service. Box Research Materials Program for and the time allotted therefor can be State Street li. .kvilli, M1ryland 20850. translations submitted to the National obtained by a prepaid telephone call to (" State Streer trett. Endowment for the Humanities for the Designated Federal Employee for registered un6 retor Nationa/ Institute ofLaw projects beginning April 1.1980. this meeting, Mr. Gary Quittschreiber, Accotmt was i ntandCriminalfustice. Stephen [. McCleary, (telephone 202/634-3267) between 8:15 of funding the e eos90 4n-a-m sssaml Advisory Committee Management Officer. a.m. and 5;00 p.m. EST. Company. 'n t.. E ease.et-es ,,1,, ey,7g, a,- tFu ooe. 7s-seac Fu.d n-a-m tes amt Dated: November 2L 1979. - aswwo coos rsas.es-as payments un& John C. Hoyle. AppI! cants pr. . L FOUNDATION ON THE
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' 3 THE HUMANITIES NUCLEAR REGULATORY ((,[ *# purchase p$r tr e s i sa Advisory Panel; Meeting COMMISSION at such freyr
- 3. 1979.
Advisory Committee on Reactor - desires.he.. t t3 the provisions of the Safeguards SECURITIES AND EXCHANGE ~ imposed ew "- COMMISSION the initialpa i as n o ice he eb'y Subcommittee on Power and Electrical a melting of the Humanities Systems; Meeting [Helease No.10946; 812-4438) na ual bo h;ld at 80015th Street The ACRS Subcommittee on Power Boston Mutual Life Insurance Co. and year for co:v i hingt:n, D.C. 20506. in room and Electrical Systems will hold an cpen Boston Mutual Ufe Variable Annuity pension or pr4 i c.m. to 5:30 p.m. on meeting on December 13,1979 in room Account A; Filing of Application Subsequent i: y, Decsmber 19.1979. 1040.1717 H St. N.W., Washington, DC November 20.197E be less th... :- - sese cf ths meeting is to 20555 to discuss several miscella.1eous allocate aII cr 3 in the matter of Boston Mutual Ufe purchase pe n* H Fallowship applications items with regard to electrical power. Insurance Company and Boston Mutual the six accesi (3 th2 National Endowment instrumentation, control, and protection i n nitits by faculty members systems in nuclear power plants. Notice Life Variable Annuity Account A.120 comprise the i institutions. of this meeting was published November Royal Street, Canton, MA 02021. (812-the Vairal& 1 l do proposed meeting will 21.1979. 4438), made the nn. t i lancialinformation and In accordance with the procedures Notice is hereby given that Boston additionalmute , form: tion of a personal outlined in the Federal Register on Mutual Life Insurance Company (the the list of accr;" .liscl:sure of which would October 1.1979. (44 FR S& loa), oral or " Company"), a mutual life insurance without the ;* company established under the laws of Commissi. I : clrarly unwarranted written statements may be presmted by the Commonwealth of Massachusetts, a the accumub: pIrsonal pm acy, pursuant members of the public, recordings will ' grinted me by the be permitted only during those portions Boston Mutual Life Variable Account A payments m Delegation of Authority to of the meeting when a transcript is bein8 (the" Variable Account"),a separate the annuity a > >ory Committee Meetings, kept, and questions may be asked only secount of the Company registered selected by th.. .ry 15,1979. I ha ve by members of the Subcommittee,its under the Investment Company Act of annuity pap 1940 ("Act") as a unit investment trust by the contu ~ ' 4 4,. &W
o 1DTTATIVE SCHEDULE PGiER AND EIECTRICAL SYSTEMS SUBC04MITTEE MEETING DECDL:R 13, 1979 1717 H Street, N. W., Washington, D.C. Room 1046 PRESENTATION '~ TIME 8:30 - 11:00 CONmOL SYSTEMS IMPACT ON SAFETY 5-10 min each item o ' Current review practices to investigate ~ control system effects on protection system NRC Staff's views whether any particular o control systems are especially more vulcrable or less vulnerable to adverse interaction o Current practice in the review of various control systems (ard their specific characteristics such ar dynamic response) in normal and accider situa-tions and the implications for fety Implications of Inverter failures on o RPS Channels that provide control signals to multiple control systems o Ciretznstances in which normal control of the NSSS depends on the reactor protection system and safety implica-tions of such situations. Specific examples are pre-trip / post-trip control actions, non-safety related RPS trips, and RPS interfaces with control systems o Ability of feedwater control systems to control flow automatically at low flow rates and the implications for safety o Possible interactions between the protection and control systems caused by maintenance and calibration (e.g., incorrect adjustment of a power level t measuring system might affect the scram level) which may lead to unsafe situations O [1'-me m D
PRESENTATICM '~ TIME 11:00 - 1:00 SAFETY IMPLICATIONS OF CON'IROL SYSTEMS AND PIANT DYNAMICS o Statement of concerns by D. L. Basdekas 30 min ~ O NRC Staff response to Mr. Basdekas' 30 min concerns 1:00 - 2:00 Lmch 2:00 - 3:30 EME3GENCY ELECURICAL POWER REQUIREMENTS / o NRC requirements for emergency power at 5-10 min operating and at new plants and lessons each item learned from Millstone 2 and ANo-2 electrical systems malfunctions o Status and results of Inverter System Reliability Studies o Bow are older plants treated o Status of shared diesels at older plants and implications, for safety o Status of Task Action Plan A-44 3:30 - 5:00 ENVIRONMENTAL QUALIFICATION REQUIREMENTS FOR CRITICAL COtGONENTS / o Effect 'IMI experience has or will have 10 min each item on qualification requirements o Current practice for assurance of capability of hermetic seals on instru-mentation and electrical equipnent required for long tenn operation follow-ing an accident o Is there or is it planned to have temperature monite-ing devices in cabinets or compartments containing solid state devices which have signifi-cant sensitivity to temperature increases ~ 3
a' ATTENDEES LIST a NRC Staff R. Satterfield S. Hanauer V. Moore D. Tondi F. Rosa T. Novak D. Basdekas M. Srinivasan ACRS l W. Kerr, Chairman J. Ebersole J. C.' Mark J. Ray ACRS Staff I G. Quittschreiber, Designated Federal Employee l J. Bickel, Fellow i Consultants W. Lipinski
- 5. Ditto E. Epler EPRI i
l R. Leyse i 1 l i i ATTACHMENT C w
DOCUMENTS PROVIDED TO THE SUBCOMMITTEE FOR THIS MEETING i View graphs shown at the meeting are provided as Attachments 1 through 13. A complete set of all handouts are provided in the meeting transcript and in the ACRS office file for this meeting. 4 3 ) 4 { 4 ~ TTACHMENT D [ A
e CURENT PRACTIE IN THE EVIBl 0F VARIOUS C0tlTROL SYSTElE ( At!D THEIR SECIFIC DiARACTERISTICS SUCH AS DYN/filC ESPONSE) IN NORMAL AND ACCIDENT SITilATIONS AND THE ItPLICATIONS FOR SAFEIY HISTORICALLY: e NO DETAILED REVIEW OF C0tRROL SYSTEMS. e SINGLE CONTROL SYSEM FAILURES ASSLNED AS INITIATING EVEPRS - NON-MECHANISTIC. e BECAUSE OF NATURE OF THE EVENTS CONSIDERED AND LIMITS IMPOSED, EVENTS ARE OVER QUICKLY. IT HAS BEEN ASSlNED THAT CONTROL SYSEM RESPONSE TIES ARE SLOW RELATIVE TO TRANSIENT. t0E EENTLY: e REVIEW OF E TRANSIENT ANALYSIS PHILOSOPHY. e CREDIT TAKEN FOR SOE CONTROL SYSTEM ACTION, E.G., e RELIEF VALVE OPERATION. e TURBINE STEAM BYPASS SYSTEM. e FEEN ATER CONTROLS 0 CONCLUDED THAT EFFECT OF CONTf0L SYSTEM ACTION WAS SMALL. W l
O IMPLICATIONS T INVERTER FAILURES ON RPS OiANNELS lliAT PROVIDE CONTROL SIGNALS TO MULTIPLE CONTROL SYSTEfB e STAFF HAS MAT N0 ETAILrd ASSESSENT OF EFFECTS OF RPS INVERTER FAILURES ON CONTROL SYSTEM e USE OF RPS SIGNALS AS INPM TO CONTROL SYSTEMS VARIES WITH VENDOR S WESTINGHOUSE - EXTENSIVE ( ~ 50 SIGNALS) e BABCOCK & WILCOX - FLm, PmER e ComuSTION ENGIEERING - NME e GENERAL ELECTRIC - NmE e E INVERTER FAILURES IN WESTINGHOUSE PLANTS CAN AFFECT MULTIPLE CONTROL SYS'IEMS. BuT MULTIPLE CONTROL / MONITORING SYSTEM FAILURES CAN ALSO OCCUR DE TO FAILURES OF C0fNON CONTROL SYS'IEM POWER SLPPl IES. e RECENT IE BULLETIN ADDRESSES THE POWER SLPPLY PROBLEM f% i F
I ABILITY OF FEERIATER C0fRROL SYSTEMS TO CONTROL FLOW AUT0mTICALLY AT LOW FLGl RATES AND THE IWLICATIONS MR SAFETY 0 FEEDiATER CONTROL SYSTEMS ARE N0' 'PTIMIZED FOR Flai CONTROL AT LD4 POWER S FLOW SIGNALS ESS ACCtRATE e VALE CONTROL MORE DIFFICULT 9 NEED FOR OPERATOR INTERACTION 4 VALVE LEAKAGE IW ORTANT ti SAFELY IMPLICATIONS THOUGHT TO BE SMALL O RECENT EVENTS AT BABCOCK & hiLCOX PLANTS HAVE RECEIVED CONSIDERABLE ATTENTION e Nt11EROUS FEEDiATER EVENTS HAVE LED TO TRIP 4 CAUSED IN PART BY REDUCTION IN OVERPRESStRE TRIP SETPOINF 0 STAFF IS REASSESSING ADEQlRCY OF FEED 4ATER CONTROL WITH EWHASIS ON ICS t 1% W LJ
e CIRClfSTANCES IN MIIG fMAL CONTROL OF THE NSSS DEPBOS ON THE EACTOR PRDTECTION SYSTEM #0 SAFETY ItPLICATIONS OF SUG SITUATIONS. SPECIFIC EXNRES AE PE-TRIP / POST-TRIP CONTRDL ACTIONS, NON-SAFETY ELATED RPS TRIPS, #0 RPS INTERFAES WITH C0tfiROL SYSTBS e PRE-TRIP CONTROL ACTIONS e ROD RutEACKS, WITHDRAWAL PROHIBITS ON APPROAOi TO DtBR/ POWER LIMITS. e TURBItE RUtBACK FOLLOWING ROD DROP. O POST-TRIP CONTROL AcrIONS e CLOSURE OF TURBINE STOP VALVES ON SCRAM. e OPENING OF POIN ON HIGH PRESSLRE TRIP. e tkw-SAFETY IhlATED IRIPS e REACTOR TRIP ON IURBINE TRIP. e REACTOR TRIP ON LOSS OF F.W. e STAFF EVALUATES THE ACCEPTABILITY OF SUCH CONTROL ACTI0tB ON A CASE-BY-CASE BASIS. GENERALLY N0 f CREDIT IS TAKEN FOR THESE TRIP / CONTROL ACTIONS. L-TRIPS / CONTROL ACTION CONTRIB!HE TO SAFETY TO THE EXTENT THAT TRIPS ARE AVO 0 LPSETS ARE AVOIE D.
8 POSSIBLE INTEPACTI0tB BEI)EEN THE PROTECTION AND WIRROL SYSTEFS CAUSED BY f%INTENANCE AND CALIBPAT (E.G., INCORECT AIUUSTEtR OF A POWER LEVEL KASURING SYSTEM MIGHT AFFECT TIE SCP#1 LBED kHICH f%Y LEAD TO UfEAFE SIlllATI0t6 e THERE HAVE BEEN INSTANCES OF SUCH INTERACTIONS e ZION - LOSS OF ALL LEVEL INDICATIONS e IIdl MISCALIBRATION OF ALL FLUX POWER CHANtELS e # D LOSS OF 3/l1 RPS INVERTERS, LOSS OF OFFSITE POWER, ETC. e STAFF HAS RELIED ON TRAINIts OF UTILITY PERSONNEL TO PREVENT MAINTENANCE / CALIBRATION PROBLEMS. e EVENTS ARE MORE FREQLENT THAN DESIRABLE. THE ISSLE REf% INS A STAFF CONCERN. a
STAFF ESPONSE TO SAETY CONERNS RAISED BY m. BASEKAS Sut%RY e STAFF AGREES WITH NEED TO GIVE GREATER REGULATORY ATIENTION TO CONTROL SYSTEM DESIGN. OPERATING EXPERIENCE CLEARLY SHOWS THAT CONTROL SYSTEMS PLAY AN Iff0RTANT ROLE 'iN PLANT RESPONSE TO REAL EVENTS. 6 I!E DISAGREE WITH S PORTIONS OF THE PROPOSED ETHOD OF RESOLUTION. 2 e THE PROPOSAL TO REDUCE POWER AT ALL OPERATING PLANTS. e A NLFSER OF EFFORTS ARE PLANED / UNDERWAY TO RESOLVE ISSLE. hb-
DISCUSSION e PRESENT APPROAW TO ASSESSING AEQlRCY OF RPS HAS DRAWBACKS e CONTROL SYSTEM FAILURES / MALFUNCTIONS NOT TREATED COBPREHENSIVELY G DIFFICULT TO EMONSTRATE WAT SAR CHAPTER 15 ANALYSES SLFFICIENTLY BOUND ALL CREDIBE EVENTS e THE ROLE OF CONTROL SYSTEMS IN THE INITIATION AND MITIGATION OF LPSET CONDITIONS NEEDS TO BE BE UNERSTOOD AND WE IlPORTANCE OF CONTROL SYSTEMS SHOULD BE REFLECTED IN NRC CRITERIA. e SEVERAL EFFORTS ARE PLANED / UNDERWAY e SHORT TERM LESSONS LEARED REQUIREENT. e BABCOCK & WILC0x ICS REA e kVELOPENT OF ESIGN CRITERIA FOR CONTROL SYSTEMS e A-17 e LER REVIEWS e LONG TERM LESSONS LEARNED - ~ A
STAFF APPROAW O MAKE USE OF SEVERAL ETHODS OF ANALYZING CONTROL SYSTEM FAILtRES e ANALYSIS OF OPERATING EXPERIENCE /POSTlLATED EVENTS e FAULT TREE ANALYSIS e REA e SYSTEM SIMULATIONS 8 WE DO NOT BELIEVE THAT e REQUIRING REAS FOR ALL CONTROL SYSTEMS IS AN APPROPRIATE FIRST STEP e A mTAILED REPRESENTATION OF SYSTEM STABILITY ANALYSIS IS REQUIRED TO IDENTIFY AND RESOLVE MOST (DNTROL SYSTEM PRmLEMS e THE EED FOR ERATING OF OPERATING PLANT HAS NOT BEEN DEMONSTRATED C e l--
FACTORS IN Tile RELIABILITY OF VITAL INSTRUF.LNT POWER SUPPLIES (l!!VERTERS) 1. RELIABILITY OF THE POWER SOUPCES SOURCE-BATTERYCHARGERJ}D. D.C. SOURCE - BATTERY A.C. BUS ALTERNATE AC SOURCE - A.C. BUS 2. RELIABILITY OF STATIC If!VERTER 3. RELIABILITY OF STATIC (AUTOMATIC) TRANSFER SWITCH I4. TESTABILITY OF AUTO TRANSFER OPERAT10N (AtlD NEED FOR PERIODIC TESTING) 5. ADEQUACY OF PRE 0PERATI0f'AL TESTING OF COMPLETE SYSTEM 5. ADEQUACY OF SYSTEM STATUS MONITORl!!G, ALARMS AND INDICAT!0NS 7. ADEQUACY OF OPERATIONAL PROCEDURES FOR LOSS OF A VITAL BUS ADDITIONAL CONSIDERATION: THE DISTRIBUTION OF INSTRUP.ENTATION AND C0" TROL LOADS ON THE VAi,10JS VITAL BUSES TO PRECLUDE ADVERSE SYSTE.V.S I!!TERACTIOMS ON LOSS OF ONE VITAL BUS.
SAME DIVISION 460 V AC 30 4BO V AC 36 ) ) ~_ .B AT TE RY BATTERY C HARSE R ,1 ) =
- 25 v CC
) COLA TR . _ _A N S p__. q l l l MN I ) l l L _ __ ___J STATIC TNVERTER ) 120 V AC to l M ' '#- No )- -- I - -{' NC TRANSPER SW VITA L 12.0 v A t i4 ) ) ) v v v TY P t C t. *_ cy, F FIG I-TYPICAL IN STR UMENTATION POWE R SUPPLY
480V AC 34 4'30 V AC 3 0 4-60 V AC 30 ) ) c EATTERY CHARGER BATTERY ') = 12 5 V DC SOLA TR AL' S ) r__ _ _ _ _,e i I I L__.. _ _ _l INVE RTE R UNIT ) ) vv )E Y r'-- 7 'i STATIC l 8 INVERTER I L _ _ _,_ _ _ _.J FIG. 2 r------ g 9l TRAN5ER SW l STATIC I TYPIC AL IN STRy-120V AC id MENTATION POWER SUPPLY L-__T___J ) VITAL 120 V l AC 16 i l i ~ T ' m ~. t. ' m... ^.. T ,3, 3, I r p. // Y V f
%/ " g ( - N e ,nsv ^. h;p,k h,I -.s 'ri Ll51 OF In51ktAllons tert 011d seeMED g3gst DIL5EL stamT045 N WIM M RAIIE OF sen2, EC3 no. OF N0. Or (ACM OG _. 818!'?' 18E8NWy gg wir 0 W m0 or ak ) I m ustts 1 & 2 merwy bases share the four W*s a 51 AG Of 101E me. WWH - '.1400 10240 See temasts re gut,,d loans for safe shutdem of bem etts s Of SE's marary 3. Tvrf Ctep)_InKl_lai 2e60
- 888 4 (Shared) 4 IG's are dedicated automatically te De 4 eme..
ggg 4 4 2850 11400 10240 See senarts gg gg,333 na tlc manust s.ultth. lag of the SG.'s te. Unit. .e..fors.fa s.us ., 3 4 mene re .e g 4 g3 3g mA LIC .e c oi, to s.,,i, iCC5 ies.s.,.op 3 iS400 5=2 See -,ts mg*pg,yy s. e . (5,,a,s.) cm leg SM.326 SIA LIC DG capactt,y for (CC5 to both mits st=1taneemst 8800 4916 2470 2700 c %erten. lies feuer 3 g (5. tag) 0 2 Calvert Cliffe 108 317.318 pga 13C gi, capacity for ECC5 to teth units st=Itassess0. 13000 The 4960 2600 criterten. (talttasseses 2 I (5= tag) 3 5 at Dr capactt,y for (CCS te both units semitaneousE Stele Campes its 275.323 Fun M50 1950 1464 2850 criterten. (Pec1fSc 94 4 I I (588"g) 2 LIC 3 (Commemunalth 1 2 (wared) 3 9 4015 17925 18654 4333 DC capactty for (CC5 to beta mits sleuttanoeust 232.249 But g,,, gen gg3 c,gge,sen, 6 g ($mlag) 2 9 2850 2360 14250 7460 36a2 D6 capactt, for ECCS te both units slamitaasmus' Lit .5 Me,364 Ptst Farley ggg 2 I (5= tag) ,,g g,gn, (Alcheme femurl g 3 listch 143 4 (5 hared) 42cis 14000 11769 9339 3 et a gG s required for t0CA I unf t. safe shut' llc 321,M6 gun 4 geene E PCI 364.3M 8M8 DG capacity for (CCS to both wits steltmieous hupe Creek )42 (9telle Service 2 I ($ stag) 2600 IM 7644 5278 ? crt urta N 5 3 OL III*3I4 3'8 e eeni ?o i g
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si li i 8 8 i i i l w j 8-8 I I I i 1 .- s 3.- I -s Jg! 1 1 1 1 1 1 w =- M 3 sl. :.0. t = ^ 5 ? i =, 5 = s s s N a g e 3 t 1 .1 I -I G 1 i 1 ~ %\\ $1' JI$ I I I I I j i =:.. *, i s z ~, ". ~' - - - - - - - - - - -. L ]a -
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- 80. Of E ACM M W ICO SIAu se 101 AL tu.
t es tstaC f htDICATLD klar./ WANES (Ew.2ma, lar Idl4L 06 LORO/Lali Mlh. 1005 SIArm Editsit no. Irrt (tm >1aulfj un Of Dh's suu s/ alt DG's/ tali ur.'s aAllhbl CA. Cliv ikel L 040/testi l'"I alianass herth Anne 54 404.406 PW KP 3 2 l l Ratism hot WA e (,.pgg) Est4<sted h/A N/A % design steelar le that listed for hery 9 2. Peum totten 2&3 277.238 but LIC 4 4 mane 4 (wered) 32ts) 12e00
- 420 See amaras 3 of 4 DG's requered for LOCA I emit. safe shee~
(falleestphie tiestric) Polet teach l&2 266,303 Pist LIC 2 2 name 2 (wared) 2450 5100 2140 M h rts (telsc.JBSch6ges SG swalty for ECG to 6 eta un8ts sleuttaneewsto Peuer Co.) ce I terten. Pralrle Island 182 2s2.306 Pim LIC 2 2 here 2 (wared) 3m W te Romerts (awthwe Sutes i swactti for ECC5 to bet *.mits steeltaneously. Pomer) cre terten. Clales 162 264.266 Inst LIC 3 2 I I (5= lag) 2850 6360 4to! See tamaras a th ur caputty fw LCC5 to bort emits slanettenne.ilyc Edises) IE***- krry 162 2h0.269 Pto LIC 3 g i I (ktag) 2850 8650 6000 2500 gygpgg) 4 <specsty for (CC5 to beta entts stauttaneewelyc 6 r I terten. // ks 162 3s7.3ae ham QL 4 4 hone 4 (hered) 4100 34 00 8462 / (pense, peu,e g L 4ght C4.) See senarts ar. sen,. city for ECC5 to heth units staulaw.ty. Ut terlen. 3.rsey Pt. 3:1 260.211 f*C tl< 2 2 anae 2 (hem 4) 2849 W IW 1487 Ca. < ee. H y for 6 00 se one eate safe shmeda.e et[ (Florlde phuar & tight) odeltleael emerpacy power capactty. Im l&2 25%.304 Pt88 L 'E I 3 i( '*9i ~ 'her is ICC5 te both netts seen,g senr. ey, (Casmeammalth (deses) But inits I. Besign criterlee for easite emergency 6.uwer sw+ly is to teve the seq.tred capetity tw shutdemn of both units postulatlag a design bests accident la ens unit. 2. Steer of Construttlen Iems: tlC. Lleensed te Operate Shared. D/s, el;I, ply pg.or L. ans eeevyeng but of ettner one er erlaas.184 these buses. a. flaal Steges of Omtalatag Operat enu ll...e PCP. Post tenstruaties Pomit hteg . p/,,,gli '*eapls puner to the meery. asp bus of the accteret < ,,9y gg, f
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