ML20245B107
| ML20245B107 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/15/1989 |
| From: | Zech L NRC COMMISSION (OCM) |
| To: | Packard R HOUSE OF REP. |
| Shared Package | |
| ML20245B109 | List: |
| References | |
| NUDOCS 8906230026 | |
| Download: ML20245B107 (1) | |
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UNITED $TATES NUCLEAR REGULATORY COMMISSION TMurley/JSniezek Vstello
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%,6,,%.[ June 15, 1989 JBlaha Jpartlow CHAIRMAN GHolahan i MVIrgilio i GKnighton 0GC DMossburg The Honorable Ron Packard MKrebs United States House of Representatives DHickman Washington, D.C. 20515 JLee PD #5 GT file
Dear Congressman Packard:
NRC PDR PD #5 r/f I.am responding to your letter of May 11, 1989, regarding the restart of San Onofre Unit 1. The Commission appreciates your comments on the Nuclear Regulatory Commission's (NRC) review and evaluation of.the technical issues affecting the restart of Unit 1.
As you noted, we did receive a request to reopen the public comment period on certain license amendments. That request was denied on May 12, 1989. On May 15, 1989, the NRC staff issued Amendment No. 127 to the operating license for Unit 1. This amendment' authorizes operation ~of the unit, subject to certain monitoring and-inspection requirements to confirm the condition of the reactor vessel thermal shield. These requirements provide reasonable assurance that the health and safety of the public will ,
not be endangered. 'On May 16, 1989, the staff concurred in the licensee's evaluation of the remaining technical issues and authorized restart of Unit 1.
I have enclosed copies of the NRC's May 15 and 16, 1989 corres-pondence to the licensee for your information. If you have any further questions on this matter, please contact me.
Sincerely, (M. .
Lando W. Zech Jr.
Enclosures:
- 1. Letter from C. M. Trammell to
- K. P. Baskin dated May 15, 1989 l with enclosures
- 2. Letter from Dr. T. E. Murley to Dr. L. T. Papay dated May 16, 1989 Originated: NRR:Trammell ;
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UNITED STATES y W . g- .
NUCLEAR REGULATORY COMMISSION
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Mr. Kenneth.P. Baskin
.Y!ce President- 1 Southern California Edison Company 2244 Walnut Grove Avenue Post Offico Box 800 Rosemead, California 91770 l
Dear Mr. Baskin:
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SUBJECT:
ISSUANCE OF AMENDMENT NO. 127 TO PROVISIONAL OPERATING LICENSl SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NO. 1 (TAC NO. 71853) j 1
.The Commission has issued the enclosed Amendment No. 127 to Provisional !
Operating License No. DPR-13 for San Onofre Nuclear Generating Station, Unit No. 1. The anendment consists of changes to the operating license in response i
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to your application dated February 17,1989, as supplemented March 21 and 23, and May 3 and 8,1989.
I The amendment provides for a reactor vessel thermal shield monitoring program and mid-cycle inspection until the thermal shield fasteners are repaired during the. fuel cycle XI refueling and 10-year ASME Inservice Inspection.
SCE is requesteo to oevelop and submit for staff approval a conceptual design and plan for the repair of the thermal shield. Specific subjects that should be addressed are plans for the existing bolts that are not broken, the design of new flexures and modification to the limiter keys. Please provide this information within 90 days. 4 When the thermal shield and core barrel are removed, an. ultrasonic test of the support block ledge should be performed from the inside of the core barrel. An cgG @ f Uc_ b D 6~ 3w , - --- -_-- _ _
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Mr. Kenneth P. Baskin May.15, 1989 ultrason'c examination should also'be performed on a representative sample of.
the core barrel-to-lower support plate weld. A visual examination siald be performed of.the entire weld from both the inside and outside surface.
Copies of our related. Safety Evaluation and Notice of Issuance are also enclosed.
Sincerely.
CAcl af. /r Charles M. Tramell, Senior Project Manager Project Directorate V ;
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Division of Reactor Projects III, i IV, V and Special Projects
Enclosures:
- 1. Amendment 11o.127 to License No. DPR-13 2.- Safety Evaluation 3 Notice of Issuance cc w/ enclosures:
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'Mr. Kenneth P. Baskin Southern California Edison Company San Onofre Nuclear Generating Station, Unit No. 1 CC Mr..Kenneth P. Baskin Vice President Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770 David R. Pigott Orrick, Herrington & Sutcliffe 600 Montgomery Street San Francisco, California 94111
.Mr. Robert G. Lacy Manager, Nuclear San Diego Gas & Electric Company -
P. O. Box 1831 San Diego, California 92112 Resident Inspector / San Onofre NPS
.U.S. NRC P. O. Box 4329 San Clemente.. California 92672 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego 1600 Pacific Highway Room 335 San Diego, California 92101 Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596
' Mr. Paul Szalinski, Chief i Radiological Health Branch State Department of Health Services 714 P Street, Office 81dg. #8 Sacramento, California 95814 4
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SOUTHERN CALIFORNIA E0lS0h COMPANY
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DOCKET NO. 50-206 SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NO. 1 AMENDMENT TO PROVISIONAL OPERATING LICENSE Amendment No.127 License No. DPR-13.
- 1. The Nuclear Reg'ulatory Commission (the Comission) has found that:
A.
The application for amenament by Southern California Edison Company l and San Diego Gas and Electric Company (the licensee) dated l
February 17, 1989, as supplemented March 21 and 23, and May 3 ano 8, 1989 complies with_the standards and. requirements of the
' Atomic Energy Act of 1954, as amencea (the Act), and the Commission's regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the regulations of the Comission; C.
There is reasonable assurance (1) that the activities authorized by this aniendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conoucted in compliance with the Cornission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Comissien's regulations and all applicable requirements have been satisfied. '
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Accordingly, the license is amended by the addition of new paragraph 3.M as' indicated in the attachment to this license amendment.
3.
This license amendment is effective as of the date of its issuance and must.be fully implemented as oescribed in the Attachment.
FOR THE NUCLEAR REGULATORY COMMISSION
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George f Knighto 'birector Project Directorate V Division of Reactor Projects III',
IV, Y and Special Projects Office of Nuclear Reactor Regulation L
Attachment:
License Condition 3.M Date of Issuance: May 15,1989 l
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3.M cvele X Thermal Shield Monitorine Procram The neutron monitor the noise / loose-parts detection system shall be used to condition of the reactor vessel thermal shield throughout Cycle X or until repair. Periodic monitoring of both ,
neutron noise and loose-parts vibrations confirms that no long term unacceptable trend of degradation is occurring. The details of this program are described below.
(1) The unit will be shut down no later than June 30, inspect the condition of the thermal shield. 1990 to (2)
During the first 7 days of 2 '85% power, interim acceptance criteria for neutron noise / loose-parts monitoring will be developed.
final acceptance Thesecriteria interim is criteria developed.will be utilized until the Final acceptance criteria for neutron monitoring will be established by performing noise / loose-parts baseline evaluations for 45 calendar days at 2 85% power fellowing return to service for Cycle X operation. The base line data will be established by recording a minimum of 16 segments of data information, each of 20 minute duration at 2 85% power.
Adjustments to the acceptance criteria will be made for cycle burnup and boren concentration changes throughout the cycle.
(3) The neutron noise / loose-parts monitoring system shall be OPERABLE in MODE 1 with:
a) At least two horizontal loose-parts detectors monitored for at least five (5) minutes 2 times per day; and, b) at least three (3) neutron noise inputs monitored for at least twenty (20) minutes once a week, and be analyzed for cross coherence. power spectral density', including phase and (4) The data provided by the loose-parts / neutron noise monitor shall be analyzed once per week and compared with the established criteria. If the data exceeds the acceptance criteria:
a) Within 1 day the NRC will be informed of the exceedance.
b) Within 14 days the conditions will be evaluated and a report provided to the NRC documenting future plans and actions.
Amendment No. 127
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c) l The plant will be shutdown should the remaining flexure be demonstrated failed.
(5)
Each channel of the loose-part detection system shall be demonstrated OPERABLE in MODE 1 by performance of a:
a) CHANNEL CHECK at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> I b) '
CHANNEL TEST mt least once per 31 days 1
The surveillance requirements for neutron noise monitor are l l
the Power Range Neutron Flux. covered by the Appendix A Technic (6)
With the neutron inoperable noise for more / loose-parts than 7 days detection instrumentation 1 Report to the Commission pursu,antlicensee shall submit a Special (
j Specification 6.9.2 within the nextto Appendix A Tecnnical 3 days outlining the 1' cause of system to the malfunction operable status. and the plans for restoring the (7) 1 In the case indicated of asensors, on site seismic event of 0.25g or greater as f initiated. Before a. controlled operations shut down are resumed, shall be {
it will be de=enstrated to the seismicthat no thermal shield damage has occurred event. due 3
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(8)
The provisions of Appendix A Technical Specification 3.0.4 are not, applicable to this license condition.
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i Amendment No. 127 i
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SAFETY EVALUATION EY THE OFFICE 0F NUCLEAR REACTOR REGULAT RELATED.TO. AMENDMENT.NO.127TO PROVISIONAL OPERATING LICEN i SOUTHERN CALIFORNIA EDISON.CONPANY SAh.DIEGO GAS.AND ELECTRIC COMPANY SAN ONOFRE NUCLEAR. GENERATING STATION, UNIT NO. 1 i
DOCKET NO. 50-206-1.0 INTR 0'D0CTION By letter dated February 17, 1989, as. supplemented March 21 and 23, and May 3 and 6, 1989, Southern California Edison Company (SCE or the licensee) requested a change to Provisional Operating License No. DPR-13 for ,
operation of San Onofre Nuclear Generating Station, Unit No.1, located in San Diego County, California. <
2.0 DISCUSSION In response to an alert from the reactor vendor that reactor vessel thermal shield festeners at another facility had been found degradea, SCE inspected the thermal-shield for SONGS-1 on January 3-4, 1989. The thermal shield at San Onofre Unit I surrounds the reactor core barrel.
It is 21" thick and about 10 feet in height, and weighs 48,000 lbs. It is supported at the bottom by six support blocks and thirty bolts which attach It to the core barrel. Support at the top is proviced by six !
flexures and 4 limiter keys. Ftve of the six flexures have been known i to have been broken since 1978.
The licensee described the inspection results and presented video tape j recordings at a January 27, 1989 meeting. During the last refueling '
outage visual examinations were performed with the internals installed .
using a high resolution underwater television camera system. Although the core was loaded during the inspection, selected fuel assemblies were shuffled to provide access.
The licensee confirmtrd that five of six thermal shield flexure fixtures are broken as detected in a previous inspection. .Three out of thirty thermal shield support block bolts are broken. These are the 7/8-inch top bolts in support blocks at the O' and 240* locations. No other signiti-cant degradation was observed visually. Ultrasonic testing was not performed.
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- The licensee has evaluated operation with the thermal shield in.the L concition worst observed expected, and worst considered credible, threeconceivable.
and worst cases which it characterizes as:
-The worst expected case involves the degradation of bolts at the third support block, and the sixth flexure remaining intact. The worst credible case assumes that all support blocks degrade (all bolts broken) and the last flexure breaks. The worst conceivable case involves the thermal-shield dropping or meving downward eleven inches to rest on the core barrel radial support keys.
In addition to the analyses presented by the licensee, the licensee proposes to inspect the thermal shield during a June 1990 mid-cycle outa
.using tion. the same equipment and rethods used during the January 1989.ir;specge The licensee also proposes to use two monitoring methods while in operation to detect any further degradation of the thermal shield: -
neutron noise monitoring and loose-parts monitoring. The 11censee :
i proposes to shut down if it determines through the monit uing program that the sixth flexure has failed.
3.0 EVALUATION The video tapes recorded. curing the visual examination demonstrate that the thernal shield is still in its original position at this time. The tapes do not show any evidence of motion of the thermal shield. The tapes show that three bolts (two in one block; one in another) are protruding sufficiently far beyond allowable tolerances that it is reasonable to assume that they have drifted inward from vibration and are broken.
Because the inspection was only visual it cannot be known if these are ,
the only broken or cracked bolts. Licensee's vibration analysis concludes j that the 240' and O' blocks are degraded and that the 300' block would ;
probably degrade during cycle X.
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Furthermore, the licensee states and the inspection does demont,trate that the thermal shield is not in the " worst credible" condition or close to it because the last flexure is still intact and no support block wear or thermal shield motion has occurred. Support block wear would be expected if all of the bolts and dowel pins in a block were failed. No evidence exists to suggest that any individual support block assembly has progressed to this condition.
The vibration analysis predicts that a third support block will probably degrade during operation in cycle X, but that no damage will occur to the thermal shield. The analysis performed by the licensee used a simplified model consisting of beam elements and springs to represent ifnear and rotational stiffnesses of the system. The staff reviewed the pertinent information provided by the licensee and concluded that there are serious flaws in the methodology, modeling and in the evaluation of stresses l
which would result from the impactive loads on the support blocks induced by the vibratory motion of the thermal shield. Because the analysis was found to be unacceptable by the staff, the license has been requested to
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l perform a mid-cycle inspection and to improve the proposed monitoring program whereby any further degradation of the shield supporting elements personnel.
operating could be quickly detected and appropriate action taken by At the meeting with the licensee on May 1, 1989, the NRC staff presented its requirements for an inspection of the thermal shield at the mid-cycle outage and changes to the proposed license conditions on thermal shield monitoring. The licensee agrced with the staff position and confirmed this agreement in its letters to NRC deted May 3 and 8, 1989.
In evaluating the safety issues regarding the thermal shield the staff took under consideration the following sequence of events which must take place prior to the situation which may cause a safety concern. The scenario which would cause a concern is that the shielo could drop to the bottom coolant of core.
to the the reactor vessel and therefore obstruct the flow of .
In order that such a situation could exist the shield must be deprived of its supporting elements and the following stages of further degradation would have to occur:
Failure of the sixth flexure Failure of the all bolts at each support block Shearing off the support blocks which hold the shield in the present position, and (4) Failure of the lower core radial supports The staff criteria require that the licensee prov Me an edequate neutron noise monitoring program which will detect any further degradation of any of the above elements and that the plant will be shut down itsnediately ,
after failure of the remaining flexure, thus precluding any further deterioration of the reactor internals. The staff believes that such an I arrangement coupled with the mid-cycle inspection provides adequate assurance of safety.
The noise signal from the ex-core power range neutron flux detectors will be recorded periodically and analyzed to monitor internal vibrations of the thermal shield. Four accelerometers mounted on the reactor vessel flange will monitor acoustical noise in order to detect the possible appearance of loose parts in the lower dome of the vessel.
I The neutron noise analysis will probably not be effective in detecting i gradual degradation of the fasteners, but failure of the last flexure i
would allow a large beam-mode oscillation at a much lower frequency which would be detectable. The I occur, as discussed above. plant would be shut down for repairs should this )
i The three bolts which were found to be broken will likely drift out all the way anc become loose parts at some point in cycle X. These parts will most likely fall to the bottom of the pressure vessel because of ,
t their weight and settle in a location of low flow velocity. Detection of loose parts such as these under these circumstances would not be likely
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due to the arrangement of the accelerometers which are mounted on the reactor vessel flange. In the unlikely event that the loose parts are lifted up against the flow distribution or core support plates, no adverse impact is expected, and these impacts may be detectable since these locations comunicate acre directly with the accelero-meters.
The licensee and consultant (Westinghouse) have analyzed the changes in reactor coolant flow to the core in the event the shield should tilt or drop.11" to the core barrel radial supports. The changes in flow and l
flow distribution would be minor and within the design parameters, and l are therefore acceptable.
We conclude that operation in cycle X as proposed is acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
Pursuant to 10 CFR 51.21, 51.32, and 51.35, an environmental assessment and finding of no significant impact have been prepared and published in the Federal Reaister on May 11 1989 (54 FR 20459). Accordingly, based upon the environmental assessme,nt, the Commissicn has determined that the issuance of this amendment will not have a significant effect on the quality < the human environment.
5.0 CONCLUSION
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered te operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations end (3) the issuance of this amendment will not be inimical to the common defense ano security or to the health and safety of the public.
Principal Contributors: R. Lipinski L. Lois C. Tramell M. Hum Dated: May 15, 1989
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UNITED STATES NUCLEAR REGULATORY COMMISSION SOUTHEkN CALIFORNIA EDISON COMPANY, ET AL.
DOCKET NO. 50-206 NOTICE OF ISSUANCE.0F MIENDNENT.TO PROVISIONAL OPERATING LICENSE The U.S. Nuclear Regulatory Comission (Comission) has issued Amendment No.127to Provisional Operating License No. DF;t-13, issued to Southern California Edison Company and San Diego Gas and Electric Company (the licensees), for operation of the San Onofre Nuclear Generating Station, Unit No.1, located in San Diego County, California. The amendment was effective as of the date of issuance.
The amendment provides for a reactor vessel thermal shield monitoring pro-
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gram and mid-cycle inspection until the thermal shield fasteners are repaired during the fuel cycle XI refueling and 10-year ASME Inservice Inspection.
The application for the amendment complies with the standards and requirementsoftheAtomicEnergyActof1954,asamended(theAct),andthe i Comission's regulations. The Comission has made appropriate findings as required by the Act and the Comission's regulations in 10 CFR Chapter 1, which are set forth in the license amendment. i Notice of Consideration of Issuance of Amendment and Opportunity for Hearing in connection with this action was published in the FEDERAL REGISTER on March 2, 1989 (54 FR 8854). No request for a hearing or petitions for leave to intervene were received. Subsequent to issuance of this notice, the licensees l
provided supplemental information by letters dated March 21 and 23 and May 3 l and 8, 1989. These letters provided additional information and revised c.umitments encompassed by the original notice.
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The Commission has prepared an Environmental Assessmect related to this action and has concluded that an environmental impact statement need not be prepared because operation of the facility in accordance with this amendment will have no significant adverse effect on the quality of the human environment.
For further details with respect to the action see (1) the application for amendment dated February 17, 1989, as supplemented March 21 and 23 and May 3 and 8, 1989, (2) Amendment No.127to License No. DPR-13, (3) the ,
Comission's related Safety Evaluation and (4) the Commission's Environmental Assessment.
All of these items are available for public inspection,at the Commission's Public Document Room, 2120 L Street NW., Washir.gton,20555, DC and at the General Library, University of California, P.O. Box 19557, Irvine, California 92713.
A copy of items (2), (3) and (4) may be obtained upon request -
t addressed ' o the U.S. Nuclear Regulatory Commission, Washington, DC 20555, Attention:
Director, Division of Reactor Projects - III, IV, V and Special Projects.
Dated at Rockville, Maryland this 15 day of May,1989.
FOR THE NUCLEAR REGULATORY COMMISSION 0 h, /r Charles M. Trammell, Senior Project Manager Project Directorate V Division of Reactor Projects III, IV, V and Special Projects Office of Nuclear Reactor Regulation 1
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UNITED STATES NUCLEAR REGULATORY COMMISSION wAsmucrow, p. c.nasas -
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. J Docket No. 50-206 1
Dr. Larry T. Papay, Senior Vice President ~
Southern California Edison Company Post Office Box 800 i 1
2244 Walnut Grove Avenue Rosemead, California 91770 j
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Dear Dr. Papay:
SUBJECT:
0PERATION OF SAN ONOFRE UNIT 1 This refers to the NRC Confinnatory Action Letter (CAL) dated January 31, 1989 and the CAL followup letter dated February 8, 1989. These letters identified certain technical issues to be resolved before Unit I restart and requested your assessment of the aggregate significance of the various single failure and other design problems identified in recent sonths.
As discussed during our May 1, 1989 meeting and documented in the enclosed meeting report, your letters dated March 17 and April 18, 1989 presented the bases for your conclusion that Unit I could safely return to service. We concur with your characterization of the identified problems and recognize that you have established programs to identify other potential deficiencies.
be We also by identified understand that these ongoing there well may(e.g.other programs design
, enhanced engineering / design deficiencies hereaft activities, design basis upgrade program) and expect that they will be assessed and handled consistent with established procedures and the requirements of your license. Accordingly, the NRC hereby concurs with your intention to restart San Onofre Unit 1.
This conclusion was reached in coordination with the Region Y Regional Administrator and is also based on your satisfactory response to NRC concerns, as documented in the meeting sumary and your written certification dated May 12, 1989 that all comitments made to the NRC for actions to be completed during the Cycle 10 refueling outage have in fact been completed.
Sincerely,
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dCL om s E. M h rqctor Office of Nuclear Re c or egulation
Enclosure:
Meeting Sumary -
ccw/ enclosure:
See next page _ <M rnlD)'1 O I VO '
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, [e .i l Mr. Kenneth P. Baskin Southern California Edison Company San Onofre Nuclear Generating Station, Unit No. I cc Mr. Kenneth P. Baskin -
Vice President Southern California Edison Cosiparty 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770 David R. P19 0tt Orrick, Herrington & Sutcliffe 600 Montgomery Street San Francisco, California 94111 Mr. Robert G. Lacy-Manager, Nuclear San Diego Gas & Electric Company 5 P. D. Box 1831 San Diego, California 92112 Resident inspector / San Onofre NPS U.S. NRC P. O. Box 4329 San Clemente, California 92672 Mayor City of San Clemente San Clemente, California 92672 Chaiman Board of Supervisors County of San Diego 1600 Pacific Highway Room 335 San Diego, California 92101 l
Regional Administrator, Region Y I U.S. Nuclear Regulatory Comission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 -
Mr. Paul Szalinski, Chief Radiological Health Franch i State Department of Health Services 714 P Street. Office B1dg. #8 Sacramento, California 95814 -
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