ML20127M636
| ML20127M636 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 11/26/1992 |
| From: | Robinson W PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20127M631 | List: |
| References | |
| NUDOCS 9211300346 | |
| Download: ML20127M636 (9) | |
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PORTLAND GENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD AND PACIFIC POWER & LIGilT COMPANY 1
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' Operating License NPF-1
- L3cket 50-344 License Change Application 227 l
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! This License Cnange Application (LCA) requests a change to l Operating Licence NPF-1 for the Trojan Nuclear Plant. This LCA proposes to defer the unscheduled steam generator inservico inspection required by Technical Specification 4.4.5.3.c.1, Inspot.tien Frequencies.
I, W. R. Robinson, being duly sworn, subscribe to and say that I am the Vice President, Nuclear for Portland General Electric Company, the applicant herein; that I have full authority to execute this !
! oath; that I have reviewed the foregoing; and that to the best of my knowledge, information and belief the statorents made in it nre true.
T Date November 26, 1992 By W. R. Robinson Vice President, Nuclear i
On this day personally appeared before me W. R. Robinson, to me known to be the individual who executed the foregoing instrument, and ackn"wledged that he signed the same as his free act. ;
GIVEN under my hand and seal this 44 th day of November 1992.
LancO]/7 et%OOLaJ Notary Public in and for the 9
State of Oregon ResidingatIhaditid My commission expiren%ehn /9f/
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I 9211300346 921126 PDR ADOCK 05000344 P PDR
, a UllITED STATES OF AMERICA 1:UCLEAR REGULATORi' COMMTSSIOff l
In the Matter of )
)
PORTLAND GENERAL ELECTRIC COMPANY, ) Docket 50-344 Tile CITY OF EUGENE, OPEGON, A!!D ) Operating License NPF-1 PACIFIC POWER & LIGilT COMPANY )
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(TROJAN NUCLEAR PLANT) )
l CERTIFICATE OF SERVICE '
I hereby certify that copies of License Change Application 227, to the Operating License for the Trojan Nuclear Plant, dated November 2{ , have been served on the following by hand delivery or deposit in the Un ted States mail, first class, this)f, th day of i Novemoor 1992:
State of Oregon i Department of Energy 625 Marion St NE Salem 03 97319 Mr. Michael J. Sykes Chairman of County Commissioners Columbia County Courthouse St. llelens OR 97051 s
/)l. 4. Chernoff/
Manager, Licensing On this day personally appeared before me 11. K. Chernoff, to me known to be the 11dividual who executed the foregoing instrument, and acknowledged that he signed the same as his free act.
l GIVEN under my hand and seal this J44 th day of Novembrar 1992.
La M&)))? . [ iWQWO Notary Public in and for the State of Oregon Residing at hdoried My cor.. mission expires thug /H/
. . Trojan Nuclear Plant Document Control Desk e i Docket 30 344 November 26,1992 I License NPF 1 Attachment 1 l
' Page 1 of 7 l LICENSE Cll ANGE Al'.1'llCATION 221 SUSISlARY l On November 9,1992, the Trojan Nuclear Plant (TNP) was shut down due to a steam generator i tube leak that exceeded the primary to secondary leakage limits of Technical Speci6 cation i 3.4.6.2, " Reactor Coolant System Operational Leakage The tube leak in the "11" Steam Gen-
' erator was rapidly detected by radiation monitors instalbd to detect nitrogen 16 in the secondary system. This allowed plant operators to promptly initiate a plant shutdown and isolate the af-fected steam generator. Operators minimized the subsequent primary to secondary leakage by equalizing the steam generator pressure with the pressure in the reactor coolant system. The ini-tial leakage rate was approximately 100 gallons per day. During the plant shutdown, however, .
the leakage rate increased beyond technical speci6catien limit of 130 gallons per day (Technical
. Specification 3.4.6.2," Reactor Coolant System - Ope *ational Leakage"). The radioactive release from the plant was limited to less than 0.1 percent of the release permitted by the technical 4
speci6 cations (i.e., approximately 5x10 mrem at the boundary of the unrestricted area). A Li-censee Event Report, as required by 10 CFR 50.73, " Licensee Event Report Syuem", will pro-vide more detailed infonnation on the pl,mt shutdcwn.
The " Technical Evaluation of the November 4,1992,Stean Generatcr Tube Lea" at the Trojan Nuclear Plant" describes: 1) the actions taken to identify the cause of the leak,2) the corrective actions taken to stabilize and plug the tube, and 3) the inspections and evaluations completed to coannn the acceptability of the sleeves that remain in service.
The leak was caused by the failure to stress relieve the welds properly in one tube support plate sleeve which was installed during the 1991 refueling outage. The inadequate stress relief was caused by failure to position properly the stress relief heater probe that was inserted intc the tube to perform the stress relief process.
A program was developed to evaluate the other tube support plate sleeves installed in the TNP steam generators. The ugective of this evaluation was to assure that the remaining sleeves were properly stress relieved. The program included eddy current testing of the remaining sleeves to detect changes in the +ube material associated with the stress relief process. The program also included a review of records cegarding the heater pneumatic sensing device pressure and heates coil temperatures recorded during installation of the sleeves. This evaluation concluded the re-maining sleeves were properly stress relieved.
Eddy current inspections of the inservice tubes adjacent to the leaking tube were also perfonned to ensure that these tubes were not damaged by the tube leak or during the plant shutdown. The leaking tube was stabilized in the defect area to prevent potential damage to adjacent tubes and removed from service by plugging. The integrity of the steam generators has been ( aonstrated and the plant is ieady to return to power operation.
Tmjan Nuclear Plant Decument Contiol Desk
- Docket 50 344 November 26,1992 ,
License NPF-1 Attachment 1 Page 2 of 7 This license amendment request proposes to defer the unscheduled steam generator inservice in-spection required by Technical Specification 4.4.5.3.c.1 following primary to secondary tube leakage in excess of technical speci6 cation limits. Additional inspections are ne'. appropriate since the integrity of the steam generator tubing has been adequately demonstrated and as such additional inspections would result in unnecessary personnel radiation exposure and prolonged operation at the reduced reactor coolant system insentory level during the inspections, EXISTING TECilNICAl. SPECIFICATION REQUIREMENTS Technical Speci0 cation 4.4.5 provides the innrvice inspection requirements for steam generator tubing. A program of periodic scheduled inservire inspections is required by this specification to ensure that the structural integrity of this portion of the reactor coolant system is maintained.
Inservice inspection of steam generator tubing is performed to maintain .,urveillance of the conditions of the tubes in the event that there is evidence of mechanical damage or progressive degradation due to design, manufacturing errors, or inservice conditions that lead to corrosion.
inservice inspection of steam generator tubing also provides a means of characterizing the nature and cause of any tube or tube sleeve degradation so that corrective measures can be taken. The program for inservice inspection of st am generator tubes is based on Regulatory Guide 1.83, Revision 1, " Inservice Inspection of Pressurized Water Reactor Steam Generator Tubes", and Regulatory Guide 1.121," Bases for Plugging Degraded PWR Steam Generator Tubes," as ap-propriate.
In addition to periodic scheduled inspections, Technical SpeciGcation 4.4.5.3.c requires un-scheduled inservice inspectiam following events which could potentially place unusual stresses on the steam generator tubeuioss of coolant accidents, main steam line or main feedwater line breaks, or seismic events); or following unanticipated tube degradation indicated by primary-to-secondary tube leakage in excess of the technical specification limits. The required inspections consist of examination of an initial sample of at least three percent of the steam generator tubes from the tube sheet on the hot leg side of the steam generators, completdy around the U bend to the top tube support plate on the cold leg side.
HASIS FOR AMENDMENT REQUEST Primary to-secondary leakage in excess of technical speci0 cation limits may indicate unantici-pated tdbe wall degradation due to a previously unknown mechanism or due to an unexpected acceleration of previously identified degradation mechanisms. In such cases, an unscheduled inservice inspection is warranted to provide an assessment of the overall condition of the steam
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generator (s). In this event at TNP, the cause of the tube leak is evident and the potential for fur-ther tube degradation is limited to a denned set of tubes and a specific tube region (i.e., tube sleeve locations). An unscheduled inservice inspection under such circumstances is not war-ranted since the specific inspection scope required by the technical speci6;ation would not be necessary to address the identi0ed cause and would result in unnecessary personnel radiation ex-
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l, . Trojan Nuclear Plant Document Control Desk i e i Docket 50 344 November 26,1992 ;
j License NPF-1 Attachment I
- Page 3 of 7
- posure, prolonged operation at reduced reactor coolant inventory, and unwarrtnted down time j
. for the plant. Based on experience gained in previous steam generator inservice inspections, an
- inservice inspection of the four steam cenerators would require up to 24 days to completc.. This j estimated schedule assumes parallel in pection efforts in the four steam generators. Based on i this schedule,it is estimated that approximately 95 person rem would be expended during this
} inspection effort in accordance with the requirements for co rective action contained in Appen-i dix "B" to 10 CFR 50," Quality Assurance Criteria For Nuclear Power Plants and Fuel Repro-j cessing Plants", specific and appropriate actions have been taken to address the identified cause
{ of the tube leak and to ensure the integrity of other steam generator tubes.
The cause of the primary to secondary leakage identified on November 9,1992, has been estah-j lished as an isolated failure to perform post kinetic weld stress relief properly on a single steam j generator tube support plate sleeve. The potential for other similar failures was limited to the j remaining 1095 tube sleeves in service. The examination of these sleeves in combination with t review ofinstallation records and additional testing and analyses have demonstrated proper in-l stallation of the other tube sleeses. These actions ensure the integrity of the reactor coolant pres.
l sure boundary. Addi ional inspections would serve no purpose other than a general assessment ,
i of the condition of the steam generators. Such a general assessment of the condition oft he
- steam generators is accomplished by the nonnat scheduled inservice inspections required by Technical Specific ions 4.4.5.3.a and 4.4.53.b.
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i DESCRIPTION OF Cil ANGE i
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, The proposed change adds a footnote at Technical Specification 4.4.5.3.c.l. This footnote al-
! lows the deferment of the required unscheduled steam generator inservice inspection until the i refueling outage currently scheduled for the Spring of 1993. A copy of the current technical
! specification for which changes are proposed is provided in Appendix A. Appendix B provides l a copy of the same technical specification with the proposed change annotated.
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NO SIGNIFICANT li AZARDS CONSIDERATION DETERMINATION j In accordance with the requirements of Title 10 to the Code of Federal Regulations, Part 50.92-
- (10 CFR 50.92), this license amendment request involves no significant hazards considerations i based upon the following:
I Standard 1 - Does the proposed license amendment involve a significant increase in the-
- j. probability or ceasequences of an accident previously evaluated?-
!- General Design Criteria 14, " Reactor Coolant Pressure Boundary," and 31, " Fracture Prevention
! . of Peactor Coolant Pressure Boundary," of Appendix A " General Design Criteria for Nuclear i Power Plants," require that the reactor coolant pressure boundary have an extremely low proba-
- bility of abnormal leakage, of rapidl> propagating failure, and c' gross rupture. General Design 1
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, Trojan Nuclear Plant Document Conttel Desk
. . Docket 30-344 November 6,1992 License NPF 1 Attachment 1 Page 4 of 7 Criterion 15, " Reactor Coolant System Design," further requires that the reactor coolant system be designed with suf0cient margin to ensure that the design conditions of the reactor coolant pressure boundary are not exceeded during any condition of nonnal operation, including antici-pated operational occunences.
The technical specification requirement for inspection of steam generator tubes are based on Regulatory Guide 1.83 - Revision I," Inservice inspection of Pressurized Water Reactor Steam Generator Tubes." The specified program of periodic inservice inspecticas is intended to ensure that the structural integrity of this portion of the reactor coolant system is maintained in accor.
dance with the General Design Criteria discussed above.
These periodic inservice inspections of steam generator tubing maintain surveillance of the conditions of the tubes to detect evidence of mechanical damage or progressive degradation due to design, manufacturing errors, or inservice conditions that had to corrosion. Inservice inspec.
tion of steam generator tubing also provides a means of chuacterizing the nature and cause of any tube or tube sleeve degradation so that corrective measures can be taken, in addition to periodic scheduled inspections, the technical specifications require unscheduled inservice inspections following events that could potentially place unusual stresses on the steam -
generator tubes (loss of coolant accidents, main steam line or main feedwater line breaks, or seismic events); or following unanticipated tube degradation indicated by tube leakage in excess of the technical specification limits for primary to-secondary leakage. This additional inservice inspection requires an initial examination of at least a three percent random sample of the tubes in the steam generators.
The proposed change allows a one time defennent of the unscheduled inservice inspection of steam generator tubes required following the November 9,1992 primary-to-secondary tube leak.
The cause of the tube leakage has been detennined, and appropriate correaive actions specific to the cause of this event have been taken. These actions have established that the observed primary to secondary leakage resulted from an isolated problem during the installation of a sleeve in a single steam generator tube and have confinned that a similar problem dia not occur during the installation of the other sleeves in the TNP steam generators. Alternate inspections i
have been performed to provide assurance that the other steam generator tube sleeves are proper-
- ly installed.
This proposed license amendment does not involve any changes to the plant or to the methods of operation of any plant system important to safety. The consequences of a postulated steam gen-erator tube rupture have been previously analyzed.
4 Implementation of the proposed I!cerse amendment would not result in any reduction of the in-tegrity of the steam generator tubes, and the requirements of General Design Criteria 14,15 and 31 will continue to be satisfied and there will be no increase in the probability of a rupture of a steam generator tube or other posti lated acc' *ents.
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. . Trojan Nuclear Plant Document Control Desk
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, . Docket 50 344 November 26,1992 License NPF 1 Attachment 1 i Page 5 of 7
{ The consequences of a postulated steam generator tube rupture have been previously analyzed.
As described in Section 15.6.3 of the TNP Final Safety Analysis Report (FSAR), the results of )
this ana;ysis are derived by taking conservative assumptions relative to the radioactivity level
- present in the reactor coolant, the rate of primary to secondary leakage, and the amount of steam j released from the plant. The proposed change deals only with the requirements for inservice in.
j spection of steam generator tubes during shutdown and does not affect any parameters impacting i the consequences of such a postulated accident.
j Therefore, implementation of the proposed license amendment will not involve a signi0 cant in.
- crease in the probability or consequences of any previously evaluated accident, t
y
{ Standard 2 - Does the proposed lleense amendment create the possibility of a new or 1 different kind of accident from any previously evaluated? j
. Implementation of the requested technical specification change does not involve any changes in i the physical plant or to the methods of operation of any plant system important to safety. Alter-
! nate inspections, testing and evaluations have been conducted to provide assurance that the in-
- tegrity of the steam generator tubes is maintained as required by General Design Criteria 14,15, j and 31. TNP FSAR Section 15.6.3 describes the analysis of a rupture of a ster,m generator tube.
l TNP Technical Speci0 cation 3.4.6.2 limits the maximum leakage rate through any one steam i generator to 130 gallons per day. Tl.is limit precludes the potential for excessive leakage during
- j. operation and requires prompt shutdown of the plant if exceeded. rJew or different tube rupture
[ events or causes of these events are not postulated as a result of this amendment.
Therefore, implementation of the proposed amendment would not create the possibility of a new j or different kind of accident from any previously evaluated.
J
- Standard 3 Does the proposed !! cense amendment luvolve a significant reduction in the- '
j margin of safety?
i j_ As described above, the requested change to the TNP Technical Speci0 cations does not reduce
! steam generator tube integrity margins. The technical speciHeation requirements for repair and
! plugging of potentially degraded steam generator tubes maintain margins consistent with Regu-latory Guide 1.121. This regulatory guide describes methodology acceptable to the NRC staff
) for meeting General Design Criteria 14,- 15, and 31 by minimizing the likelihood of a steam gen-l erator tdbe rupture. The inspections and testing conducted as a result of this event, in conjunc-tion with the regularly scheduled inservice inspection program based on Regulatory Guide 1.83 -
. Revision 1, also provide assurance that the required steam generwur tube design margins will be
- maintained, i- ,
! Therefore, implementation of the proposed license amendment would not result in any reduction
- in a margin of safety.
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, . Trojan Nuclear Plant Document Control Desk
.- . Docket 30 344 November 26,1992 License NPF 1 Attachment i Page 6 of 7 ENVIRONMENTAls IMPACT DETERMINATION This amendment r. quest meets the etiteria specified in 10 CFR 51.22(c)(9) for a categorical ex-clusion from performing an environmental review since it involves a change to an inspection re- i quirement for a part 50 licensee and: i (1) The amendment involves no significant hazards consideration.
As demonstrated above, this proposed amendment does not involve any signiHeant hazards con-sideration.
i (ii) There is no significant change in the types or significant increase in the amounts of any effluents that may be released off site.
Implementation of the proposed amendment will not result in any change in the manner of op-eration of the facility or in the amount or nature of any effluents. The proposed amendment de-fers, on a one time basis, an unscheduled steam generator inservice inspection which has been shown to be unnecessary. As demonstrated in the no significant hazards consideration deter.
mination above, there is no increase in the probability of steam generator tube failure or leakage as a result of this proposed amendment. Therefore, there is no significant change in the types of, ,
or significant increase in, the amounts of any effluents that may be released off site.
(ill) There is no significant increase in individual or cumulative occupational radiation exposure, implementation of the proposed amendment will result in a reduction in occupational radiation exposure since it will climinate unnecessary inservice inspections of steam generator tubes dur- .
ing the current outage, inservice inspection of steam generator tubes is a significant source of occupational radiation exposure, JUSTIFICATION FOR EMERGENCY LICENSE AMENDMENT REQUEST The steam generator inspection and repair efforts performed in response to the November 9, 1992 tube leak event were completed on November 24,1992. In order to prevent a delay in start up of the plant, this license amendment is needed by December 2,1992 to allow scheduled
- entry into Mode 4 operation. Per conversations with the NRC staff, this schedule will not allow time for processing of this amendment by normal or exigent means. Therefore, it is requested that this request be processed as an emergency amendment in cecordance with 10 CFR 50.91(a)(5). '
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i 3, Trojan Nuclear Plant Document Control Desk 4 , Docket 50 344 November 26,1992 License NPF-1
,1 Attachment 1 '
- Page 7 of 7 f
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An emergency situation as discussed in 10 CFR 50.91(a)($) exists since failure to promptly issue the amendment will prevent resumption of power operation of the TNP. This situation resulted from the unforeseen tube leakage, and did not result from a lack of timely action by Portland i
General Electr c Company. The need for the amendment was not reasonably forcreeable until j
the tube leak event cecurred on November 9,1992 and the isolated nature of the problem was s
subsequently identined. This license change application has been prepared promptly following I,
the identincation ofits need.
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Subsequent to the initial detection of primary-to secondary leakage, the plant was promptly shut-down and extensive efforts were immediately undenaken to identify the source of the leak and to l detennine its cause and extent. During the subsequent investigations and inspections, the NRC staff and Oregon Department of Energy personnel were kept closely informed of the situation and the progress of these efforts. When the results of these efforts indicated that the scope of the
.' problem was limited and was appropriately addressed by specific cause related inspections, evaluations, and repairs (as opposed to the unscheduled inservice inspection specided in the TNP j
Technical Speci6 cations), this license amendment request was prepared in an expeditiom, man-i ner.
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The alternative to this license amendment is to perform the unscheduled inservice inspection of the steam generators. This inspection would not provide signincant additional assurance of the integrity of the steam generato;s, since the cause of the leak at the tube sleeve has been deter-I mined and the remaining sleeves in service have been inspected, evaluated and found satisfacto-ry. The performance of this inspection would re> alt in unwarranted personnel exposure, j
extended operation of the plant at reduced reactor coolant system inventory conditions, and a
)
significant delay in returning the plant to power operation. Based on experience gained in pre-i vious steam generator inservice inspections, an inservice inspection of the four steam geaerators would require up to 24 days to complete. This estimated schedule assumes parallel inspection efforts in the tbur steam generators. Based on this schedule it estimated that about 95 person-rem would be expended during this inspection effort.
i As a compensatory measure for deferment of the unscheduled inspections, examinations and analyses were conducted to con 6rm that the other sleeves in the TNP steam generators were pro-per!y stress relieved. An inservice inspection of the steam generator tubes will be conducted j
during the upcoming refueling outage in accordance with Technical Specifications 4.4.5.2 and ;
j 4.4.5.3.
,t This emergency amendment request is a one time deferral of the unscheduled inservice inspec-tion required by Technical Specification 4.4.5.3.c.l. The inspection will be conducted during l the normally scheduled inservice inspection to be perfonned during the refueling outage current-l ly scheduled for the Spring of 1993.
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