Information Notice 1998-07, Offsite Power Reliability Challenges from Industry Deregulation

Offsite Power Reliability Challenges from Industry Deregulation

ML031050278
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	02/27/1998
From:	Roe J W Office of Nuclear Reactor Regulation
To:
References
IN-98-007, NUDOCS 9802240067
Download: ML031050278 (7)

X 71 C sa'UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555-0001February 27, 1998NRC INFORMATION NOTICE 98-07: OFFSITE POWER RELIABILITY CHALLENGES FROMINDUSTRY DEREGULATION

Addressees

All holders of operating licenses for nuclear power reactors except those who have ceasedoperations and have certified that fuel has been permanently removed from the vessel.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alertaddressees to a potential concern relating to electric power industry deregulation that couldadversely affect the reliability of offsite power sources, i.e., power from the transmission systemgrid to nuclear power plants. It is expected that recipients will review the information forapplicability to their facilities and consider actions, as appropriate. However, suggestionscontained in this information notice are not NRC requirements; therefore, no specific action orwritten response to this notice is required.

Description of Circumstances

On July 11, 1989, safety systems at Virgil C. Summer Nuclear Station experienced a sustaineddegraded voltage condition and as a result the safety buses were automatically transferred fromthe offsite power system to onsite standby diesel generators. The degraded condition wascaused by a turbine trip and deficiencies in the offsite power system's transmission networkequipment. The transfer of power supplies was initiated by operation of degraded voltageprotective relays, as designed. Non-safety system loads remained operable while being poweredfor approximately 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> from the degraded offsite power source. (LER 50-395/89-012)On November 5, 1991, the licensee for Arkansas Nuclear One, Units 1 and 2 reported that, hadits 500kV auto-transformer been lost during summer peak conditions, the 161kV system mightnot have been able to maintain adequate voltages to support the operation of the safety systemloads of both units. (LER 50-313/91-010)On April 15, 1992, Northeast Nuclear Energy Company reported that under certain operatingconditions of the transmission network (i.e., during heavy load conditions), a failure oftransmission system equipment may cause a trip of all three Millstone units and a loss of offsitepower to the station. This operating condition was precipitated by the economic displacementof oil-fired generating units by non-utility generators and by the addition of other generatingcapacity (Seabrook and Hydro-Quebec) to the transmission network. (LER 50-245/92-020)?PD 1re-F Normf, 1g-0o7 80a.2 7q ~ r 1l~lill~lill~lill~lililuill1!\i

IN -07February 27, 1998 On April 14, 1993, Wisconsin Public Service Corporation reported that under certain transmissionline contingencies, a potential existed for the Kewaunee Nuclear Power Plant grid to becomeunstable and cause all offsite power sources into the plant to trip. (Ref: LER 50-305/93-010)On December 30, 1993, Northeast Nuclear Energy Company reported that under certainoperating conditions of the transmission network (i.e., Millstone Units 2 and 3 off line), thetransmission network may not have sufficient capacity to permit the continued operation of safetysystem loads from offsite sources following a trip of Millstone Unit 1. (LER 50-245/94-001)On August 8, 1995, Pacific Gas and Electric Company (PG&E) reported that under certainoperating conditions (i.e., a high system load with a specific 230kV transmission line out ofservice), the transmission network may not have sufficient capacity to permit the continuedoperation of the safety system loads from offsite sources following a trip of one of the two DiabloCanyon units. (Ref: LER 50-275/95-007)On August 10, 1996, a transmission line sagged into a tree in Oregon creating a ground fault thatprogressed into a major fault on the western Interconnection. The subsequent transient resultedin the tripping of both Diablo Canyon, Units 1 and 2 (LER 50-275/96-012) and Palo Verde, Units 1and 3 (LER 50-528/004).During the summer of 1997, concerns were expressed about the impact of electric peakconditions on the offsite power sources for nuclear power plants located in the Midwest andNew England. In addition, the licensee for Clinton nuclear station sought an exemption fromoffsite power regulatory requirements because of its analysis that offsite power would becomeinadequate under certain summer peak conditions following the loss of the nuclear unit.Recent NRC inspection findings and Licensee Event Reports have indicated instances when gridstability analyses had not been updated by the licensees to reflect changes in the grid powersystem. Office for Analysis and Evaluation of Operational Data study C97-01, "Grid PerformanceFactors" dated March 20, 1997, identified a Oneed to monitor grid conditions on a regular basis."DiscussionIn 1988, NRC issued the station blackout (SBO) rule. The requirements of 10 CFR 50.63, "Lossof All Alternating Current Power," specify that each light-water-cooled nuclear power plant beable to withstand and recover from an SBO (i.e., a loss of offsite and onsite emergency ac powersources) for a specified period. The NRC review of licensees' analyses to assess thevulnerability of offsite power and the time required for recovery indicated that for most nuclearpower plant sites the grid was stable and reliable.Historically, grid control is decentralized and each utility or a small group of utilities forms acontrol area containing customers for which it Is jurisdictionally responsible. The control areasform reliability councils that establish operating standards by consensus. These agreements, inturn, became the factors that determine the reliability of the grid and the bases for the availabilityof the offsite power system. Although the grid operating standards that evolved in the pastprovided reasonable grid reliability, events like those discussed herein reveal vulnerabilities ofthe electrical grid either through actual challenges or through licensee's analyses to assess theadequacy of the offsite power system.

INS '7Feb,--dry 27, 1998 The present grid management may be dismantled or restructured by two factors that areemerging: non-utility generation and deregulation. It Is anticipated that in the future, powersuppliers, whether utilities or independent power producers, will actively compete for sales tocustomers who may be located anywhere on the power grid. This option creates multiplecombinations of generating units going on and off the grid based on economic and performancerelated consequences. Regional grid control could be the responsibility of centralizedindependent system operators (ISOs). The responsibilities and authority of an ISO are yet to bedefined, but It is expected that the ISO, or a similar entity, will be charged with maintaining gridreliability to facilitate the marketing of power. It is uncertain how the historic mechanisms forreliable operation will change under the new grid operational structure. The Department ofEnergy has sponsored a Task Force on Electric System Reliability to examine the implications ofindustry deregulation on the Nation's electric power supply.The capacity and capability of the offsite power system for each nuclear power plant could besignificantly influenced by the decisions emerging from these forthcoming changes. Since thecapability of the offsite power cannot be tested except when challenged in an actual event, thedesign bases of the offsite power can only be assured through an enveloping analysis thataccounts for the full spectrum of grid loading and transient conditions that support the operabilityof safety systems. The NRC Standard Review Plan Section 8.2 provides current guidance forassessing the adequacy of the offsite power system. It addresses grid analyses thatdemonstrate acceptable voltage and frequency when subjected to scenarios involving loss ofnuclear unit generation, loss of the largest other unit, or loss of the most critical transmission line.Although the above events discussed may not demonstrate present generic weaknesses inlicensees' processes, it is vital that licensees continue to ensure that the design bases withrespect to the reliability and stability of the offsite power sources do not degrade during the life ofthe nuclear facility. The capacity and capability of the offsite power system for nuclear powerplants are important elements to be factored into the management of the changes resulting fromindustry deregulation.This information notice requires no specific action or written response. If you have any questionsabout the information in this notice, please contact one of the technical contacts listed below orthe appropriate Office of Nuclear Reactor Regulation (NRR) project manager.orig /s/'d byJack W. Roe, Acting DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical Contacts: Ronaldo V. Jenkins, NRR Thomas Koshy, NRR301415-2985 301415-1 176E-Mail: rvj2nrc.gov E-Mail: txk@nrc.govA-1T E~A FiL ;1 JAckETFAttachment: Ust of recently issued Information NoticesOGC Concurrence (R. K Hoefling) 214198, PGEB Id 2/17198 (T. Essig),AEOD Idc 2/12/98 (E.Rossi) & Tech Editor 1/27/98DOCUMENT NAME: S:%DRPM SEC\98-07.IN -SEE PREVIOUS CONCURRENCETo receive a copy of Nhis document, Indicate In the box C=Copy wlo attachmentlenclosure E=Copy with attachmenUendosure N = No copylOFFICE PECB I EELB I IEELB I PECB L PECB I DRPM ANAME TKoshy* RJenkins* JCalvo* RDennig* SRichards* JRoe*DATE 2/2/98 j 2/2/98 j 2/2/98 2/10/98 2/11/98 2/17/98OFFICIAL RECORD COPY

AttachmentIN 98-07February 27, 1998 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to98-06 Unauthorized Use of Ucense to 2/19198 All NRC licensees authorized toObtain Radioactive Materials,And Its Implications Under TheExpanded Title 18 of theU.S. CodeEnvironmental QualificationDeficiency for Cables andContainment PenetrationPigtailspossess licensed material97-45, Supp. 12/17/98All holders of operatinglicenses for nuclear powerreactors except those licenseeswho have permanently ceasedoperations and have certified thatthe fuel has been permanentlyremoved from the reactor vessel98-0598-0498-0398-0298-0197-9197-90Criminal History RecordInformation1997 Enforcement Sanctions fordeliberate Violations of NRCEmployee Protection requirementsInadequate Verification ofOvercurrent Trip Setpoints inMetal-Clad, Low-VoltageCircuit BreakersNuclear Power Plant ColdWeather Problems andProtective MeasuresThefts of Portable GaugesRecent Failures of ControlCables Used on AmershamModel 660 Posilock RadiographySystemsUse of NonconservativeAcceptance Criteria inSafety-Related PumpSurveillance Tests2111/982/9/981/21/981/21/981/15/9812/31/9712/30/97All holders of operatinglicenses for power reactorsAll U.S. Nuclear RegulatoryCommission licenseesAll holders of operating licensesfor nuclear power reactorsAll holders of operating licensesfor nuclear power reactorsAll portable gauge licenseesAll industrial radiographylicenseesAll holders of OLs for nuclearpower reactors except thosewho have ceased operationsand have certified that fuel hasbeen permanently removed fromthe vesselOL = Operating LicenseCP = Construction Permit

IN9' Y, Feb~Uyxx, 1998 The present grid management may be dismantled or restructured by two factors that areemerging: non-utility generation and deregulation. It Is anticipated that in the future, powersuppliers, whether utilities or independent power producers, will actively compete for sales tocustomers who may be located anywhere on the power grid. This option creates multiplecombinations of generating units going on and off the grid based on economic and performancerelated consequences. Regional grid control could be the responsibility of centralizedindependent system operators (ISOs). The responsibilities and authority of an ISO are yet to bedefined, but it Is expected that the ISO, or a similar entity, will be charged with maintaining gridreliability to facilitate the marketing of power. It is uncertain how the historic mechanisms forreliable operation will change under the new grid operational structure. The Department ofEnergy has sponsored a Task Force on Electric System Reliability to examine the implications ofindustry deregulation on the Nation's electric power supply.The capacity and capability of the offsite power system for each nuclear power plant could besignificantly influenced by the decisions emerging from these forthcoming changes. Since thecapability of the offsite power cannot be tested except when challenged in an actual event, thedesign bases of the offsite power can only be assured through an enveloping analysis thataccounts for the full spectrum of grid loading and transient conditions that support the operabilityof safety systems. The NRC Standard Review Plan Section 8.2 provides current guidance forassessing the adequacy of the offsite power system. It addresses grid analyses thatdemonstrate acceptable voltage and frequency when subjected to scenarios Involving loss ofnuclear unit generation, loss of the largest other unit, or loss of the most critical transmission line.Although the above events discussed may not demonstrate present generic weaknesses inlicensees' processes, it is vital that licensees continue to ensure that the design bases withrespect to the reliability and stability of the offsite power sources do not degrade during the life ofthe nuclear facility. The capacity and capability of the offsite power system for nuclear powerplants are important elements to be factored into the management of the changes resulting fromindustry deregulation.This information notice requires no specific action or written response. If you have any questionsabout the information in this notice, please contact one of the technical contacts listed below orthe appropriate Office of Nuclear Reactor Regulation (NRR) project manager.Jack W. Roe, Acting DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical Contacts: Ronaldo V. Jenkins, NRR Thomas Koshy, NRR301-415-2985 301-415-1176E-Mail: rvjenrc.gov E-Mail: txk@nrc.govAttachment: List of recently issued Information NoticesOGC Concurrence (R. K Hoefling) 2/4198DOCUMENT NAME: G:ITXK\GRIDIN2.1WPD -'SEE PREVIOUS CONCURRENCETo receive a copy of this document indicate In the box C=Copy wlo aftachmentlenclosure E d: .ATo osure N = No copy[OFFICE lPECB lI EELB 1 _ EELB l PECB lI PECB I DRPMNAME TKoshy* RJenkins* JCalvo* RDennig* lSRichards'Jlel DATE j 2/2/98 [2/2/98 2/2/98 j 2/10/98 l- ;1 /98 1/ 1/98_J___A_ 18- .8--OFFICIAL RECORD COPY t CM ITre

ING' xFebkty xx, 1998 The present grid management may be dismantled or restructured by two factors that areemerging: non-utility generation and deregulation. It is anticipated that in the future, powersuppliers, whether utilities or Independent power producers, will a6tively compete for sales tocustomers who may be located anywhere on the power grid. This option creates multiplecombinations of generating units going on and off the grid based on economic and performancerelated consequences. Regional grid control could be the responsibility of centralizedindependent system operators (ISOs). The responsibilities and authority of an ISO are yet to bedefined, but it is expected that the ISO, or a similar entity, will be charged with maintaining gridreliability to facilitate the marketing of power. It is uncertain how the historic mechanisms forreliable operation will change under the new grid operational structure. The Department ofEnergy has sponsored a Task Force on Electric System Reliability to examine the implications ofindustry deregulation on the Nation's electric power supply.The capacity and capability of the offsite power system for each nuclear power plant could besignificantly influenced by the decisions emerging from these forthcoming changes. Since thecapability of the offsite power cannot be tested except when challenged in an actual event, thedesign bases of the offsite power can only be assured through an enveloping analysis thataccounts for the full spectrum of grid loading and transient conditions that support the operabilityof safety systems. The NRC Standard Review Plan Section 8.2 provides current guidance forassessing the adequacy of the offsite power system. It addresses grid analyses thatdemonstrate acceptable voltage and frequency when subjected to scenarios involving loss ofnuclear unit generation, loss of the largest other unit, or loss of the most critical transmission line.Although the above events discussed may not demonstrate present generic weakness inlicensees' process, it is vital that licensees continue to ensure that the design bases with respectto the reliability and stability of the offsite power sources do not degrade during the life of thenuclear facility. The capacity and capability of the offsite power system for nuclear power plantsare important elements to be factored into the management of the changes resulting fromindustry deregulation.This information notice requires no specific action or written response. If you have any questionsabout the information in this notice, please contact one of the technical contacts listed below orthe appropriate Office of Nuclear Reactor Regulation (NRR) project manager.Jack W. Roe, Acting DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical Contacts: Ronaldo V. Jenkins, NRR Thomas Koshy, NRR301-415-2985 301-415-1176E-Mail: rvjenrc.gov E-Mail: txk@nrc.govAttachment: List of recently issued Information NoticesOGC Concurrence (R. K Hoefling) 2/4/98DOCUMENT NAME: G:ITXK\GRIDIN2.1WPD -SEE PREVIOUS CONCURRENCETo receive a copy of this document, idicate hi the box C=Copy wlo attachmentlenclosure E=Copy with attachmentlenclosure N = No copylOFFICE PECB I EELB _L EELB I -PECB l- DRPM_NAME TKoshyl RJenkins* JCalvo* g ~ nig SRichards JRoel DATE I /== 2/2/9f 1 2/219 i ,I °B9% l I / I9tOFFICIAL RECORD COPY

IN "xFebruary xx, 1998