ML20215K004
| ML20215K004 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 06/18/1987 |
| From: | Dromerick A Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8706250185 | |
| Download: ML20215K004 (63) | |
Text
'~ ( d June 180 1987 Docket No. 50-219 Licensee: GPU Nuclear Corporation From: Alexander W. Dromerick, Project Manager Project Directorate I-4 Division of Reactor Projects I/II
SUBJECT:
JUNE 11, 1987, MEETING WITH GPU NUCLEAR CORPORATION (GPUN) TO DISCUSS MATTERS RELATED TO (1) OYSTER CREEK DRYWELL CORROSION AND (2) STATUS OF THE SYSTEMATIC EVALUATION PROGRAM (SEP) l On Thursday, June 11, 1987, a meeting was held at the NRC, Bethesda, Maryland l with GPUN the licensee to discuss (1) its program related to the drywell l corrosion at Oyster Creek and (2) the status of the Systematic Evaluation l Program. Attachment 1 is the list of participants that attended the meeting.
The corrosion of the shell was the subject of several meetings and the staff's safety evaluation dated December 29, 1986. In its evaluation the staff recuired that the licensee shall by June 30, 1987, provide comprehensive plans for mitigating the corrosive attack on the drywell shell and any other intended long-term corrective actions it may deem necessary. These plans are for staff review and approval. This meeting was to discuss such plans being developed by the licensee. l Attachment 2 is the licensee's agenda. The following is a summary of the significant items discussed and the actions taken or proposed. This program investigated the following issues:
(1) Wall Thickness Measurements - Define and Iglement Program for Ongoing Inspections, (2) Corrosion Mechanism and Arrest-Identify Mechanism, Evaluate Options . ,
to Arrest, Implement . Selected Option, -
(3) Water Leakage-Define Ongoing Inspections and Repairs to Locate and Terminate Leakage, (4) Structural Evaluation-Perform Additional Analysis, using a more comprehensive structural model, of the as-corroded drywell to confirm code allowable stresses are met and that original design stress margins are maintained.
The licensee stated that this program is supported by its in-house engineering staff and by outside consultants.
8706250185 870610 PDR ADOCK 05000219 P PDR
3-i The licensee stated that wall thickness measurements were taken at the most corroded locations, Bay 11, 17, 19. Wall thickness measurements of these Bays are presented in Attachment 2 (minimum mean wall thickness was determined to be 0.887 inches). The licensee stated that the data obtained to date indicates that previous safety evaluations are not invalidated and that measurements will be continued at outages of opportunity for several years. They also indicated that the planned outage in September for UT is not required based on data obtained to date during two previous forced outages and since more opportunities to obtain data during the current operating cycle are possible.
The licensee indicated that wastage of the drywell plate is the result of an aquecus general corrosion process influenced by localized oxycen depletion, the degree to which moisture is present, temperature and chloride centamination. They also indicated that although viable bacteria were identified in the sand and corrosion product, no evidence exists as to its involvement in the corrosion process.
With respect to drywell corrosion mitigation the licensee stated that they evaluated several alternatives for corrosion arrest. On the basis of the licensee's evaluation Cathodic Protection was selected as the method to arrest corrosion. The licensee indicated that the cathudic protection system will be installed during the 11R refueling cycle or by the end of the 12R refueling outage. The 12R refueling outage is scheduled for September 1988. The licensee indicated that small leakage from sand bed drains in Bays 11, 15 and 19 has continued intermittently and during Cycle 11, they intend to decontaminate and remove sludge from the equipment pool. The licensee will also conduct NDE and leak test the pool liner. The licensee will continue to monitor all drains.
With respect to the structural analysis, the licensee indicated that the analysis continues to demonstrate that code allowable stresses are met and the original design stress margins are maintained, even when assuming wall thickness reduced to 0.700 inches in the sand pocket region. ;
The licensee indicated that the evaluation regarding drywell corrosion at Oyster Creek was performed in accordance with 10 CFR 50.59 and that the nresentation satisfies the June 30, 1987 action item to provide to the NRC p10ns for mitigating the corrosive attack and other intended long-torm actions. No decisions were made by the staff.
With respect to the Systematic Evaluation Program the licensee presented the status of this program. Attachment 3 is the licensee's agenda. The licensee indicated that 20 issues are still open and that nine issues require action by the licensee and 11 issues require action by the NRC. The licensee recuested
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that the NRC expedite its efforts in issuing a supplement to the Integrated Plant Safety Assessment - Systematic Evaluation Program in order for the licensee to receive a full term power operating license. The staff advised the licensee of what actions must be taken before a full term operating license could be issued. It was agreed that a meeting would be held on June 30,1987 at Bethesda, Maryland to further discuss this issue.
l
/s/
Alexander W. Dromerick, Senior Project Manager Proje:t Directorate I-4 Division of Reactor Projects I/II i l
Attachments:
As stated cc w/ attachments: ;
See next page ;
i i
DISTRIBUTION Docket File.
NRC & Local PDRs PDI-4 Reading S. Varga B. Boger S. Norris A. Dromerick OGC-Bethesda E. Jordan J. Partlow .
ACRS (10) -
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cc:' Plant Service list LAP I-4 PD14)j 7 PD SNo 6/l}/87
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- 9. t ATTACHMENT 1 i
ATTENDANCE LIST 0YSTER CREEK NUCLEAR GENERATING STATION DDCKET NO. 50-219 JUNE 11, 1987 - MEETING l l
NAME ORGANIZATION Branch Elam GPUN - Project Mgr., Oyster Creek Containment Program Dana Covill GPUN - Materials Engineering, Engineering & Design Ian Monro Corrosien Service Co., LTD ]
Gary Capodanno GPUN - Director, Engineering & Design Thomas Ahl CBI - Senior Engineer Don K. Croneberger GPUN - Director, Engineering Projects Barry Gordon GE, Principal Engineer, Corrosion Performance l Conrad McCracken NRC/NRR/ECEB l Robert A. Pinelli GPUN - OC, Project Engineer Nick Trikouros GPUN, Manager Safety Analysis & Maintenance Control l Felix Litton NRC/NRR/MTEB I Chen P. Tan NRC/NRR/SGB Heikko Reponen NRC/RES/EIB(foreignassignee) l Martin W. Ebert NUS Corp. (LIS) l Yosh Nagai GPUN - Licensing ,
Nichael Laggart GPUN - Manager, OC Licensing David J. Jerko GPUN - Licensing Joe Montalbano Ebasco Services J. R. Thorpe GPUN - Director - Licensing & Reg. Affairs R. F. Wilson GPUN - Technical Director R. L. Long GPUN - Director, Planning & Nuclear Safety J. F. Stolz NRC/NRR/ Director PCI-4 F. J. Witt NRC/NRR/ Chemistry Engineer Alexander W. Dromerick NRC/NRR/ Project Manager, PDI-4 Kris Parczewski NRC/NRR/ECEB A. R. Blough, et al NRC/ Region I - Telecon 4
1
ATTACHMENT 2 4
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GPUN PRESENTATION TO NRC i 1
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1 OYSTER CREEK DRYWELL CORROSION I
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l JUNE 11,1987 1 1
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AGENDA f
- 1. BACKGROUND CHRONOLOGY 8. EL AM - GPUN
- 2. OVERALL PROGRAM TASKS B.ELAM - GPUN
- 3. WALL THICKNESS MEASUREMENTS B. ELAM - GPUN
- 4. CORROSION MECHANISM D. COVILL - GPUN 1
l
- 5. CORROSION ARREST l
l A. OVERALL EVALU ATION B. GORDON - GE jl B. CATHODIC PROTECTION 1. MUNRO - CORROSION SERVICES INC
- 6. STRUCTURAL EVALUATION T.AHL - CBI
- 7. WATER LEAKAGE B. ELAM - GPUN
- 8. CONCLUSIONS B.ELAM - GPUN L
, e
. CHRONOLOGY NOVEMBER,1986: GPUN NOTIFIES NRC OF PROBLEM DECEMBER,1986: THREE MEETINGS HELD WITH NRC DECEMBER 18,1986: GPUN LETTER AND SAFETY EVALUATION TO NRC l JUSTlFYING INTERIM OPERATION TO 12R OUTAGE, COMMITTING "TO CONTINUE THE UT SHELL THICKNESS TEST PROGRAM AT FUTURE OUTAGES OF OPPORTUNITY INCLUDING FORCED OUTAGES OTHERWISE REQUIRING DRYWELL ENTRY DURING THE NEXT CYCLE."
DECEMBER 29,1986: NRC LETTER AND SAFETY EVALUATION TO GPUN APPROVING INTERIM OPERATION TO 12R, WHILE REQUIRING THAT (1) "SHOULD THERE BE NO FORCED OUTAGES OF SUFFICIENT DURATION PRIOR TO THE MID-POINT OF THE OPER ATING CYCLE, PERFORM THE INSPECTION NO LATER THAN SEPTEMBER 30, 1987" AND (2) "GPU SH ALL, BY JUNE 30, 1987, PROVIDE COMPREHENSIVE PLANS FOR MITIG ATING THE CORROSIVE ATTACK ON THE DRYWELL SHELL AND ANY OTHER INTENDED LONG TERM CORRECTIVE ACTIONS IT MAY DEEM NECESSARY FOR STAFF REVIEW AND A P P R OV A L"
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1 PROGR AM TASKS j i
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- 1. WALL THICKNESS MEASUREMENTS - DEFINE AND IMPLEMENT 1
PROGR AM FOR ONGOING INSPECTIONS.
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- 2. CORROSION MECH ANISM AND ARREST -lDENTIFY MECHANISM, EVALUATE OPTIONS TO ARREST, IMPLEMENT SELECTED OPTION.
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- 3. WATER LEAK AGE - DEFINE ONGOING INSPECTIONS AND REPAIRS TO LOCATE AND TERMINATE LEAK AGE.
- 4, STRUCTUR AL EVALU ATION - PERFORM ADDITIONAL ANALYSIS, USING A MORE COMPREHENSIVE STRUCTUR AL MODEL, OF THE AS-CORRODED DRYWELL TO CONFIRM CODE ALLOWABLE' STRESSES ARE MET AND THAT ORIGINAL DESIGN STRESS MARGINS ARE MAINTAINED, j
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WALL THICKNESS MEASUREMENTS PROCEDURE FOR INSPECTION j
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- 1. UTILIZES D-METER (DIGITAL READOUT) l
- 2. LOOKS AT MOST-CORRODED LOCATIONS BAY 11,17,19 (3" ABOVE i
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- 3. REPETITIVE INSPECTION OF SAME LOCAliONS USING TEMPLATE AND LOC ATION MARKING ON DRYWELL WALL .
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WALL THICKNESS MEASUREMENTS UT DATA TABLE ME AN THICKNESS (STAND ARD DEVI ATION) BY LOCATION NOTE: o EACH LOC ATION - 6"x6" MATRIX WITH 49 POINT READINGS o THICKNESS SHOWN IS ARITHMETIC MEAN OF 49 POINTS o STANDARD DEVIATION IS FOR 49 POINTS WITH RESPECT TO MEAN LOCATION DEC.1986 FEB.1987 M AY 1987 58 3" U P 1.184 (.024) 1.178 (.070)
(FROM CURB) 11" UP 1.158 (.112) 1.184 (.063) 17D 3" UP 0.900 (.053) 0.936 (.079) 0.909 (.073) 14" UP 1.141 (.005) 1.140 (.043) 19 A 3" U P 0.868 (.046) 0.907 (.093) 0.887 (.080) 14" UP 1.135 (.034) 1.129 (.089) 11 A 3" UP 0.889 (.034) 0.927 (.084)/0.945 (.091) 11 C 3" U P 0.986 (.105) 0.967 (.092) 198 3" UP 0.881 (.068) 0.898 (.057) 19C 3" UP 0.865 (.068) 0.907 (.091)
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- 1. DATA OBTAINED TO DATE INDICATES PREVIOUS SAFETY EVALUATION NOT INVALIDATED.
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- 2. MEASUREMENTS WILL BE CONTINUED AT OUTAGES OF OPPORTUNITY FOR SEVERAL YEARS.
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- 3. PLANNED OUTAGE IN SEPTEMBER FOR UT NOT '1EQUIRED BASED l ON DATA OBTAINED TO DATE DURING TWO PREVIOUS FORCED I
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KEY EXAMINATION FINDINGS METALLURGICAL AND CHEMICAL l SAMPLE 2, BAY iSA, SUSPECTED PITTING 0 VISUAL EXAM - NO PITTING, LIGHT RUSTING, DRY SAND 0 METALLURGICAL EXAM - ALUMINIDE INCLUSION, DENSE ENOUGH TO ]
CAUSE UT BEAM REFLECTION O CONFlRMED ADEOUACY OF A-SCAN TO CHARACTERIZE PITTING VS.
INCLUSIOriS ;
SAMPLES 1(19C), 3(17D), 4(19A) - WASTAGE O THICK MAGNETITE CRUST BETWEEN CORE AND SAND 0 XRD IDENTIFIED FE20. AS MAJOR OXIDE PRESENT O CHLORIDE CONTAMINANTS PRESENT IN OXIDE O pH = 4 ON 1 F1 UG SURFACE SAMPLE 6, DAY 11 AH, ABOVE WASTAGE O LIGHT RUSTING O PARTICLES OF RED LEAD STILL ON SURFACE 1
O HIGH S AND Cl ON SURFACE BUT NO ELECTROLYTE O SAND HAD HIGHER LEACHABLE CONTAMINANTS THAN IN WASTAGE LOCATIONS BIOLOGICAL 0 NO SULFATE REDUCING BACTERIA, GALLIONELLA, OR PSEUDOMONAS WERE PRESENT WHICH ARE KNOWN MAJOR CONTRIBUTORS TO MIC 0 SOME VIABLE BACTERIA PRESENT; NOT LINKED TO MIC t
, CORROSION MECHANISM -
0F OYSTER. CREEK DRYWELL -
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SAMPLES O RICH 2
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gsgn (CATHODIC) Fe + + 30H - -> Fe(OH)3 t t ' 2 2 CONCRETE CONCRETE DRAIN
. I CORROSION CONCLUSIONS l
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- 1. WASTAGE OF THE DRYWELL PLATE lS THE RESULT OF AN AQUEOUS ,
GENERAL CORROSION PROCESS INFLUENCED BY LOCALIZED OXYGEN l DEPLETION, THE DEGREE TO WHICH MOISTURE IS PRESENT, I TEMPERATURE AND CHLORIDE CONTAMINAYlON.
- 2. ALTHOUGH VIABLE BACTERIA WERE IDENTIFIED IN THE SAND AND CORROSION PRODUCT, NO EVIDENCE EXISTS AS TO ITS INVOLVEMENT IN THE CORROSION PROCESS.
- 3. D-METER THICKNESS READINGS, WHICH INITIALLY WERE THOUGHT TO BE EITHER PITTING AND LATER CHARACTERIZED BY"A" SCAN UT AS INCLUSIONS, WERE CONFIRMED BY METALLOGRAPHY TO BE ALUMINIDE INCLUSIONS IN THE CARBON STEEL.
]
- 4. THE COMBINATION OF USING A D-VETER FOR ULTRASONIC THICKNESS MEASUREMENTS AND AN "A" SCAN FOR QUALITATIVE ASSES 1 MENT OF THE PLATE CONDITION ARE ADEQUATE FOR ENGINEERING EVALUATIONS.
- 5. MAJOR CORROSION IS LIM]TED TO THE STEEL IN CONTACT WITH WETTED SAND K] THIN ELEVAT]ONS 10 ' 3" to 11 ' 9". BELOW 10 ' 3",
CORROS10N IS LESS THAN O.15". THE EXTENT OF CORROSION IN THE . K ASTAGE AREAS, CONS]DERING J NDIVIDUAL READINGS, IS: BAYS 11,13, ' 17, 19 - 0. 25" to 0.41"; BAYS 1, 9 - O.15'" to 0. 25"; BAYS 3, 5, 7, 15 - NONE DETECTED.
- 6. THE AREAS OF OBSERVED CORROSION APPEAR TO BE THOSE AREAS IN WHICH THE SAND HAS REMAINED SIGNIFICANTLY WETTED. THIS WETTING MOST LIKELY OCCURRED DURING INITIAL CONSTRUCTION AND THEN PERIODICALLY AS A RESULT OF LEAKAGE.
- 7. THE AVERAGE CORROSION RATE OVER THE PAST 20 YEARS IS BELIEVED TO BE 17-20 MPY. TYPICALLY, THE RATE WOULD BE HIGHER DURING INITIAL CORROSION AND IS EXPECTED TO BE LOWER
, NOW.
RATTELLE LITERATURE SEARCH DETERMINED THAT THE CORROSION RATES, CORROSION PRODUCTS, AND pH CHANGES OBSERVED AT OYSTER CREEK ARE SIMILAR TO THOSE REPORTED IN THE LITER ATUR E.
- 8. THESE CONCLUSIONS ARE CONSISTENT WITH THOSE PRESENTED IN THE 12-19-86 NRC MEETING AND OUR SAFETY EVALUATION.
0YSTER CREEK DRYWELL CORROSION MITIGATION EVALUATION l OBJECTIVE: REDUCE THE CORROSION RATE OF THE DRYWELL IN CONTACT WITH THE SAND CUSHION TO ASSURE DRYWELL INTEGRITY THROUGHOUT THE PLANT LIFE. REQUIREMENTS:
- 1. REDUCE CORROSION RATE. ,
l
- 2. BE POSSIBLE TO IMPLEMENT AT OYSTER CREEK.
- 3. DO NOT JEOPARDIZE STRUCTURAL INTEGRITY.
- 4. DON'T M\KE POTENTIAL FUTURE SAND REMOVABLE IMPOSSIBLE.
i
- 5. MAINTAIN SAND CUSHION INTEGRITY.
1 IN ADDITION, A LIST OF DESIRABLE GOALS WAS DEVELOPED TO l EVALUATE THE ALTERNATIVES. l l l I l
l ALTERNATIVES FOR CORROSION ARREST CATHOD]C PROTECTION i PRINCIPLE: AUXILIARY ANODE AND IMPRESSED CURRENT TURNS DRYWELL INTO CATHODE. PROS: 1. FUNCTIONS WITH ADDITIONAL WATER INTRUSIONS, l 2 EASILY CONTROLLED, MONITORED.
- 3. LARGE EXPERIENCE BASE.
- 4. NO GENERATION OF WASTE.
CONS: 1 REQUIRES PERIODIC MAINTENANCE AND OPERATIONAL CHECKS. l rHEMICAL TREATMENT PRINCIPLE: CHEMICALS RETARD CORROSION AT METAL SURFACE PROS: 1. MINIMUM DOWN TIME FOR IMPLEMENTATION, CONS: 1. UNPROVEN TECHNIQUE, REQUIRES TEST PROGRAM, 2 WATER INTRUSIONS MINIMlZES EFFECTIVENESS.
- 3. MAY INCREASE CORROSION,
- 4. GENERATES WASTE, SAFETY HAZARDS.
l ALTERNATIVES FOR CORROSION ARREST (CONTINUED) l l i DRYlNG THE SAND CUSHION PR I NC I Pi. E : ELIMINATES ELECTROLYTE PROS: 1. LOWEST CORROSION RATE. (IN PRINCIPLE)
- 2. READILY MONITORED. !
l CONS: 1. DIFFICULT TO IMPLEMENT, LOW CHANCE OF SUCCESS.
- 2. EQUIPMENT DEVELOPMENT AND INDUSTRIAL SAFETY )
CONCERNS. l
- 3. FUTURE WATER INTRUSIONS COULD OVERWHELM DRYING SYSTEM CAPACITY.
- 4. COULD PROMOTE AIRBORNE RADI0 ACTIVE SPECIES.
l SAND REMOVAL AND COATINGS PRINCIPLE: BARRIER TO THE ELECTROLYTE PROS: 1. MINIMUM RISK TO REBAR OR CONCRETE. CONS: 1. UNPROVEN.
- 2. INCOMPLETE COATINGS WILT. INDUCE LOCALIZED CORROSION,
- 3. LARGE AMOUNTS OF RAD WASTE AND EXPOSURE.
- 4. HIGH MAINTENANCE.
. a ,
ALTERNATIVES FOR CORROS10N ARREST (CONTINUED) CATHODIC PROTECTION AND CHEMICAL TREATMENT PRINCIPLE: ASSUMED SYNERGISM OF CP At:0 CT PROS: 1 REDUCED REQUIREMENTS FOR ANODES AND CHEMICALS, l l CONS: 1. UNPROVEN,
- 2. ALL CONCERNS OF CT, )
- 3. UNKNOWN ADVERSE SYNERGISMS, 1
1 CATHODIC PROTECTION IS THE SELECTED ALTERNATIVE 4
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s LOG CURRENT , EVAN'S DIAGRAM FOR CATHODIC CONTROL
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e G.P.U. NUCLEAR 1 CATHODIC PROTECTION (CP) - ADDITIONAL BENEFITS I
- 1. CORROSION WILL BE MITIGATED WHETHER OR NOT WATER LEAKAGE CAN BE MINIMlZED.
- 2. OUTPUT CURRENT, OUTFUT VOLTAGE AND REFERENCE POTENTIAL SHOULD INDICATE WHEN WATER LEAKAGE OCCURS IF NOT CONTINUOUS. MAY HELP TO FIND LEAK SOURCE.
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l DRYWELL CONFIGURATION I J i
LISTDeG OF CONFIGURATIONS l CBI Configuration Description- 1 Number 1 No Sand - corroded shell in Sand Zone plus doubler plate or veld overlay. 2 No Sand - full thickness shell 4 3 Sand (275 psi /in) in Sand Pocket - full thickness shell i t 4 No Sand - corroded shell in Sand Zone plus horizontal stiffener ) i 5 No Sand - corroded shell in Sand Zone 1 6 Alternate Material (800 psi /in) in Sand Pocket - corroded'shell in Sand Zone. I 7 Sand (275 psi /in) in Sand Pocket - corroded shell in Sand Zone l l l i 1
,1JSTDIG OF IAAD CASES i
l CBI-Load Pressure Temp. Time Comment (See notes) Case # psig *F Sec. . 1 1 -2 50-150 SS Norm.0p.+0BE(No therm) 2 -2 50-150 SS Refueling +0BE(No therm) 3 62 175 0-10 OBE+10 Sec. Gradient 4 35 281 0-10 OBE+10 Sec. Gradient 5 -2 205 0-10 OBE+10 Sec. Gradient. 6 23.3 200-335 10-16 OBE+10 Sec. Gradient I 7 23.3 260 40 OBE+10 Sec. Gradient 8 23.3 260 40-160 OBE+20 Sec. Gradient 9 23.3 260-305 160-300 -0BE+20 Sec. Gradient 10 23.3 305 300-600 OBE+600 Sec. Gradient l 11 40.7 288 0-7 OBE+10 Sec. Gradient 12 hydro head N/A N/A flooded +SSE (No therm)
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P Tabulated Stress Values in Embedment Zone Load Case 6 P = 23.3 psi T = 130-335 Configuration No. 7 i Location Membrane Stresses Surface Stresses Inches above PT.10 e e e I e I O.00 5241 1572 5241 12770 3831 12770 I 4 30.78 5033 2968 5033 5218 3070 5218 44.71 4951 3334 4951 15780 6702 15780 ] 52.00 4960 8175 8175 23080 13990 23080 57.90 5054 15680 15680 14360 19050 19050 60.10 5109 18720 18720 5822 19520 19520 61.57 5110 -18940 24050 16500 -21820 32560 4 61.94 3099 -19900 23000 3630 -20620 24250 65.97 2901 -13690 16590 11040 -15580 23730 69.63 2767 -8097 10860 16200 -11430 20970 74.00 2687 -3405 6092 17590 -7315 17590 l 86.50 2655 5012 5012 13360 8019 13360 102.60 2793 7308 7308 5549 8139 8139 l t i 1 l
Capacity Margin sumary configuration 7-Corroded Shell in Sand Zone with Sand Fully Effective 4 Capacity Margins Point Governing stability allow allow Number Load Case o, og stability o, og O comp 1 3 3 2 8.54 2.06 23.9 2 3 3 2 5.81 1.06 7.51 3 3 3 2 4.55 1.30 13.8 4 3 3 2 1.07 1.49 1.60 5 3 3 2 1.08 1.05 2.05 , 6 3 3 2 1.19 1.06 1.60 7 3 3 2 1.21 1.08 1.17 - 8 3 12 2 1.96 1.36 1.07 9 3 6 2 1.20 1.47 1.03 10 3 3 12 1.11 3.71 3.18 Buckle Location 2 2 2 2.33 19.48 1.00 Top Cyl. 3 3 N/A 2.00 1.00 N/A Top Head 3 3 N/A 3.56 2.23 N/A
+
4' conclusions The analysis of the drywell for Configuration 7 (Sand in the Sand Zone and the shell corroded to .70" thick in the Sand Zone) when subjected to the load cases described yields the following conclusions: o The tensile and compressive stresses are less than the-specified allowable stress of the 1962 Issue of the ASME Code, Section VIII, including the Summer 1964 Addendam plus Code cases 1270N-5 and 1272N-5. o The tensile and compressive stresses are less than the specified allowable stress requirements of the 1986 Edition of ASME Section III, Subsection NE, and Code Case I N-284. o The more refined analysis performed in this study shows . that the minor deviation of local membrane stress exceeding 1.10 X Sm for a distance greater than JRt, as described in the " restart report" is no longer a concern. o The capacity Margin Summary shows that the lowest capacity margin based on tensile or compressive stresses occurs outside the sand pocket zone. f i o The capacity Margin Summary shows that the lowest capacity l margin based on stability is applicable to the refueling case along with a. coincident -2 psig. The validity of i this combination of loads as a design basis warrants further review.
WATER LEAK AGE OBSERVATlONS SINCE RESTART:
- 1. SMALL LEAKAGE FROM SAND BED DRAINS IN BAYS 11,15,19 HAS CONTINUED INTERMITTENTLY.
i ACTIONS PLANNED DURING CYCLE 11: .
- 1. DECONTAMINATE AND REMOVE SLUDGE FROM EQUlPMENT POOL, NDE/ LEAK TEST POOL LINER.
- 2. CONTINUE TO MONITOR ALL DR AINS.
l ACTIONS PLANNED FOR 12R OUTAGE:
- 1. FUNCTION AL TEST OF 2" CONCRETE TROUGH DRAIN UNDER REFUELING CAVITY SEAL.
i
l l FIOURE 3
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^ CONCLUSIONS l
. I f
- 1. IMPRESSED CURRENT CATHODIC PROTECTION IS THE CORROSION ARREST METHOD WITH HIGHEST PROB ABILITY OF SUCCESS. j
- 2. UT WALL THICKNESS MEASUREMENTS TO DATE INDICATE PREVIOUS SAFETY EVALUATION IS NOT INVAllDATED. MEASUREMENTS WILL BE ;
CONTINUED AT OUTAGES OF OPPORTUNITY OTHERWISE REQUIRING DRYWELL ENTRY FOR SEVERAL YEARS. j
- 3. PLANNED OUTAGE IN SEPTEMBER FOR UT NOT REQUIRED BASED ON DATA OBTAINED TO DATE. HAVE HAD SEVERAL OUTAGES OF l OPPORTUNITY TO DATE. MORE DURING THIS CYCLE ARE POSSIBLE.
SEVERAL YEARS REOUIRED TO OBTAIN MEANINGFUL CORROSION RATE ! DATA. l 1
- 4. STRUCTURAL ANALYSIS CONTINUES TO DEMONSTRATE CODE I ALLOWABLE STRESSES ARE MET AND ORIGINAL DESIGN STRESS MARGINS ARE MAINTAINED, EVEN WHEN ASSUMING WALL THICKNESS REDUCED i
TO 0.700"IN SAND POCKET REGION. I S. SELECTION OF CATHODIC PROTECTION CORROSION ARREST ON BAYS l WITH MAXIMUM CORROSION, COUPLED WITH CONTINUED MONITORING OF WALL THICKNESS BY UT AND CONTINUED EFFORTS TO IDENTIFY AND MINIMl2E FUTURE WATER INCURSIONS INTO THE SAND BED WILL i PROVIDE THE BASIS FOR ENSURING DRYWELL SAFETY FUNCTION IS MET.
- 6. THIS PRESENTATION SATISFIES THE JUNE 30,1987 ACTION ITEM TO PROVIDE TO THE NRC PLANS FOR MITIG ATING THE CORROSIVE ATTACK AND OTHER INTENDED LONG TERM ACTIONS.
i
]
i a
. . ATTACHMENT 3 SYSTEMATICEVALUATIONPROGRAM(SEP) OBHCTIVE REVIEWTHEDESIGNSOfOLDEROPERATINGNUCLEARREACIOR PLANTSTORE-CONFIRMANDDOCUMENTTHEIRSAFETY. 1 KETH000LOGYUSED
- 1. IDENTIFICATIONOfDIffERENCESBETWEENCURRENT l TECHNICALPOSITIONSONSAFETYISSUESANDTHOSETHAT EXISTEDWHENAPLANTWASLICENSED.
1
- 2. ASSESSMENT Of THE SAFETY SIGNIFICANCE Of THE
'DIffERENCESFROMANOVERALLPLANTSAFETYVIEWP0 INT.
- 3. TO ARRIVE AT DECISIONS ON WHETHER BACKflTTING WAS )
EESSARY,ENGINEERINGANALYSISANDOTHEREVALUATIONS I WEREUSEDASWELLASTHERESULTSOfAPRA. 1 1 1 i 4804g '
l SEPTOPICS-0YSTERCREEK I o ORIGINALNUMBER0FTOPICS: 137 o DELETEDNUMBER0FTOPICS: 54 (T0PICSC0VEREDBYUSIOR TMIACTIONPLANORNOT APPLICABLETO0.C.) o NUMBER 0FTOPICSREVIEWEDFOR0.C. 83 ::~300 ISSUES 0 NUMBER 0FISSUESDOSEDOUT ~280 ISSUES l 0 NUMBER 0FISSUESSTILLOPEN 20 ISSUES ! 0 NUMBEROFISSUESNEEDING 9 ISSUES .. GPUNACTIONSTOCLOSEOUT (47% COMPLETION) l 0 NUMBER 0FISSUES 11 ISSUES NEEDINGNRCACTIONSTO CLOSEOUT 4804g
i ISSUESNEEDINGGPUN
]
ACTIONSTOCLOSEOUT j
- l. IPSAR4.l(3) WATERLEVELMONITORINGINTHEINTAKE CANAL
- 2. IPSAR4.2 DESIGNOfSPECIFIEDCOMP0NENTS(SEISMIC ANDQUALITY).DOCUMENTATIONFINDINGS j INFSAR.
l
- 3. IPSAR 4.3 CONTROLROOMWALLUNDERCOMBINEDWIND ANDMISSILEIMPACTLOADING.
- 4. IPSAR4.3.1 REACTORBUILDINGUPPERSTEELSTRUCTURE:
UNDERTORNAD0WINDLOADS.
- 5. IPSAR4.6.4 PROTECTIONTOENSURESAFESHUIDOWNFOR TORNAD0 MISSILES.
l I
- 6. IPSAR 4.12 EVALUATION,ONASAMPLINGBASIS,Of SPECIFICSTRUCTURALELEMENTSPER CURRENTCODESANDLOADINGCONDITIONS
- 7. IPSAR4.16.1 PRIMARYSYSTEMLEAXAGERATEANDLEAXAGE DETECTIONSYSTEMSENSITIVITY. 1
- 8. IPSAR 4.17 P.T.CURVEBEYOND10EfPY
- 9. IPSAR 4.28 RPSMONITORSWITHINAPPROPRIATESCALE TRIPSETTINGS 4804g a --. .
ISSUESNEEDINGE ACTI0iSTOCLOSEOUT
- l. IPSAR4.6.2 TORNAD0MISSILEIMPACTTHRUTHERX BLOG. ACCESS 000R$
- 2. IPSAR4.6.4 SAFESHUT00WNF0LLOWINGTORNAD0 l MISSILES l
- 3. IPSAR 4.10(2) LEAKAGE DETECTION FOR 150. COND. PIPING f
- 4. IPSAR 4.11(1) SEISMIC PIPING ANALYSIS l
- 5. IPSAR 4.11(2) SEISMIC - CR0 SYSTEM & VESSEL INTERNAL
- 6. IPSAR 4.11(3) SEISMIC - 4160V SWITCHGEAR &
ELECTRICALPANEL l
- 7. IPSAR 4.16.2 UNIDENTIFIED LEAKAGE MONITORING (TSCR l 158) !
- 8. IPSAR4.20 PRIMARYC0OLANTCHEMISTRY
- 9. IPSAR 4.27(1) ELECTRICAL ISOLATION BET. RPS. & ,
RECORDERS
- 10. IPSAR 4.34(1) VENTILATION SYSTEM (DIESEL CAPACITY)
- 11. IPSAR 4.36 PRIMARYC0OLANTACTIVITY 4804g
. . . . I ISSUESNEEDINGGPUNACTIONS l I
- 1. IPSAR4.l(3)"PROVIDEWATERLEVELMONITORINGINTHE INTAKECANAL" l
STATUS: NRCSTAFFREQUESTEDINMAY,'87A I WRITTENDESCRIPTION0FLOWWATERLEVEL MONITORINGATOYSTERCREEK.
- 2. IPSAR4.2 "EVALUATETHEDESIGN0FSPECIFIED i COMP 0NENTSTOCURRENTSTANDARDSONA SAMPLINGBASIS,UPGRADEIFNECESSARY, !
ANDDOCUMENTFINDINGSINTHEFSARUPDATE" ! I STATUS: GPUNHASCOMPLETEDALLBUTONE(FATIGUE l ANALYSISOFRECIRCULATIONSYSTEMPUMPS) ) ' EVALUATIONS..THEEVALUATIONSAREBEING REVIEWEDINTERNALLY..THERESULTSWILL BESUBMITTED.
]
3&4.IPSAR4.3 "DEMONSTRATETHATFAILUREOFCONTROL ROOMNORTHWALLDUETOCOMBINEDWINDAND MISSILEIMPACTLOADINGWILLNOTPREVENT SAFEPLANTSHUTDOWN" IPSAR 4.3.1 "ANALYlE AND IDENTIFY ANY NEEDED MODIFICATIONSTOTHEREACTORBUILDING UPPERSTEELSTRUCTUREFORTORNADOWIND LOADS" STATUS: RECENTNRCREQUESTFORADDITIONAL INFORMATIONISBEINGADDRESSED. ,
- 5. IPSAR 4.6.4 " PROVIDE PROTECTION TO ENSURE SAFE SHUTDOWNFORTORNAD0 MISSILES STATUS: RECENTGPUNEVALUATIONINDICATESTHAT OYSTERCREEKCANACHIEVEH0TSHUTDOWN WITHEXISTINGCOMP0NENTSWHICHARE SAFETY PROTECTED FROM TORNAD0 MISSILES.
EVALUATIONHASBEENGENERATEDAND i APPROVED.THE INFORMATION WILL BE l SUBMITTED.
- 6. IPSAR4.12 "EVALUATEONASAMPLINGBASISSPECIFIC STRUCTURALELEMENTSACCORDINGTOCURRENT )
CODESANDLOADINGCONDITIONS." STATUS: 200UTOF23ISSUESHAVEBEENCLOSEDOUT PERNRCSER.RECENTNRCREQUESTFOR , ADDITIONALINFORMATIONFORTHEREMAINING i 3 ISSUES IS BEING ADDRESSED. THE RESULTSWILLBEPROVIDED. ) i i i 4804g ,
- 7. IPSAR4.16.1"EVALUATEPRIMARYSYSTEMLEAKAGERATE ANDENSURERELIABILITYANDSENSITIVITY.
OfLEAKAGEDETECTIONSYSTEMS" STATUS: (1) GPUN LETTER (7/8/86) PROVIDED JUSTIFIGTION AND REQUESTED CANCELLATION OFCONTAINMENTRAD. MONITOR MODIFICATIONS. (2) NRC LETTER (3/12/87) REJECTED GPUN REQUESTDUETOLACK0FSUFFICIENT JUSTIFIGTION. (3) FURTHER JUSTIFICATIONS WERE PROVIDED ! l DURING GPUNlNRC MEETING HELD ON 5/15l87. (4)NRCSTAFFREQUESTEDAGPUNLETTER DOCUMENTINGTHEFURTHERJUSTIFICATION.
- 8. IPSAR 4.17 " SUBMIT P-T CURVE BEYOND 10EFPY" STATUS: P-TCURVEWASBEENDEVELOPEDANDSAFETY j WILL BE EVALUATION HAS BEEN COMPLETED. I SUBMITTED.
i 4804g 1
- 9. IPSAR 4.28 " REPLACE EXISTING RPS MONITORS THAT HAVE ,
INAPPROPRIATESCALETRIPSETTINGS"
.AfFECTEDINSTRUMENTS 0 RE02A,B,C&D;DIFFERENTIALPRESSURE SWITCH FUNCTION; CORESPRAYANDISOLATION ONLOWLOWLEVEL CONCERN; SETP0INTATTHEEXTREMELOW ENDOfTHERANGE STATUS; REPLACEMENTCOMPLETE.
0 RE18A,B,C&D;DIffERENTIALPRESSURE i SWITCH. FUNCTION; AUT0 PRES $URIZATIONONLOW LOWLEVEL CONCERN; SETP0INTATTHEEXTREMELOW ENDOfTHERANGE STATUS; TESTINSTALLATIONTO DETERMINESUITABILITYOf PROPOSEDSOLUTION l 0 RE23A,B,C&D;PRESSURESWITCHES
)
FUNCTION; CLOSEMSIVONLOWSTEAM PRESSURE CONCERN; HIGHDRIfTRATES ! STATUS; TESTINSTALLATIONT0 l DETERMINE.SUITABILITYOf PROPOSEDSOLUTION
a j q l SEP-0YSTERCREEK(1) o THEPROGRAMWASINITIATEDBYNRCIN1977ONTHEPREMISE THATTHENRCSTAFFWOULDCONDUCITHEEVALUATIONAND ANALYSESOFTHEDESIGNCRITERIAFORSEPPLANTS. 1 l 0 EARLY1980'sTHECHANGEOFDIRECTIONBYTHESTAFFREQUIRED SEPUTILITIESTOCONDUCTEVALUATIONSANDANALYSES UTILIZINGTHEIROWNRESOURCES. 1 0 THECHANGEOFDIRECTIONHASCOSTGPUN: 0 ~ 4MILLIOND0LLARS 1 0 ~ 40 MAN YEARS l 0 INVOLVEMENTOFSEVERALCONSULTANTS , 4804g
SEP-OYSTERCREEK(2) o CURRENT $TATUS 0VER 95I CLOSED OUT oNONEOfTHEREMAINING0PENISSUESARERATED I HIGHORMEDIUMIMPORTANCETORISKPERNUREG l 0822(IPSAR). FINDINGS oVIRTUALLYALLTHETOPICSREVIEWEDEITHER FULLYSATISFYTHECURRENTDESIGNCRITERIAOR l INTENTOFTHECURRENTCRITERIA i oCONSEQUENTLY,THENUMBERANDTYPEOF MODIFICATIONSREQUIREDASARESULT0FTHE REPREVIEWWEREINSIGNIFICANT f CONCLUSION oOYSTERCREEKSEPHASESSENTIALLYBEEN COMPLETEDANDSERVEDITSPURPOSE. 4804g
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