IR 05000272/1987024
| ML18093A405 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 09/17/1987 |
| From: | Swetland P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML18093A403 | List: |
| References | |
| 50-272-87-24, 50-311-87-25, NUDOCS 8710020228 | |
| Download: ML18093A405 (14) | |
Text
Report No Docket No License Nos:
Licensee:
U. S. NUCLEAR REGULATORY COMMISSION 50-272/87-24 50-3H/87-25 50-272 50-311 DPR-70 DPR-75
REGION I
Public Service Electric arid Gas Company 80 Park Plaza Newark, New Jersey 07101 Facility Name:
Salem Nuclear Generating Station - Units 1 and 2
_Inspection At:
Hancocks Bridge, New Jersey Inspection Conducted:
July 21, 1987 - August 24, 1987 Inspectors:
T. J. Kenny, Senior Resident Inspector K. H. Gibson, Resident Inspector Approved by:
R. J. Summers, Project Engineer H. J. Kaplan, Lead Reactor Engineer P. 0. Swetland, Chief, Reactor Projects Section No. 2B, Projects Branch No. 2, DRP Inspection Summary:
Inspections on July 21, 1987 - August 24,.1987 (Combined Report Numbers 50~272/87-24 and 50-311/87-25)
Areas Inspected:*: Routine in~pections of plant operations including:
followup on outstanding inspection items, operatiofral safety verifiCation, maintenance, survejllance, and review of special report Identification and corrective ~ctions regarding a reacior vessel hea~ leak were inspecte The inspection involved 223 inspector hours by the resident NRC inspectors including backshift inspections on July 21, 23, and August 13 and weekend inspection on August 2, 198 The inspection involved 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> by a specialist NRC inspector.
8710020228 eo~a72 PDR ADOCK PDR G
Results:
This report documents resident inspector activities and in particular a forced outage for transformer replacement on Unit 2 and the subsequent inspection of the containment for a suspected primary lea A small reactor head leak was identified which caused a boric acid buildup on the reactor head and on the reactor stud The licensee 1 s timely investigation of changing containment conditions, and the comprehensive approach to the boric acid clean-up and verification of continued system integrity were exemplary.
- DETAILS Persons Contacted Within this report period, interviews and discussions were conducted with members of licensee management and staff as necessary to support inspection activit.
Followup on Outstanding Inspection Items (Closed)
Violation (50-311/87-18-01); This violation was issued due to the licensee's failure to properly maintain and follow procedures result-ing in a technical specification surveillance not being completed within the required tim The inspector reviewed the licensee's response and verified that immediate corrective actions were adequate and complet The licensee plans long term corrective actions to improve control of control room document The inspectors will follow the licensee's implementation and progress with regard to these items during regular monthly surveillance inspection This item is close.
Operational Safety Verification Documents Reviewed Selected Operators' Logs Senior Shift Supervisor's (SSS) Log Jumper Log Radioactive Waste Release Permits (liquid & gaseous)
Selected Radiation Work Permits (RWP)
Selected Chemistry Logs Selected Tagouts Health Physics Watch Log 3.2 The inspector conducted routine entries into the protected areas of the plants, including the control rooms, Auxiliary Building, fuel buildings, and containments (when access is possible).
During the inspection activities~ discussions were held with operators, technicians (HP & I&C), mechanics, supervisors, and plant managemen The purpose of the inspection was to affirm the licensee's commitments and compliance with 10 CFR, Technical Specifications, and Administrative Procedure. On a daily basis, particular attention was directed to the following areas:
Instrumentation and r..ecorder traces for abnormalities; Adherence to LC0 1s directly observable from the control room; Proper control room shift manning and access control;
3. *
3. *
Verification of the status of control room annunciators that are in alarm; Proper use of procedures; Review of logs to obtain plant conditions; and, Verification of surveillance testing for timely completio On a weekly basis, the inspector confirmed the operability of selected ESF trains by:
Verifying that accessible valves in the flow path were in the correct positions; Verifying that power supplies and breakers were in the correct positions; Verifying that de-energized portions of these systems were de-energized as identified by Technical Specifications; Visually inspecting major components for leakage, lubrication, vibration, cooling water supply, and general operating conditions; and, Visually inspecting instrumentation, where possible, for proper operabilit On a biweekly basis, the inspector:
Verified the correct application of a tagout to a safety-related system; Observed a shift turnover; Reviewed the sampling program including the liquid and gaseous effluents; Verified that radiation protection and controls were properly established; Verified that the physical security plan was being implemented;
.*
Reviewed licensee-identified problem areas; and, Verified selected portions of containment isolation lineup.
- 5 Inspector Comments/Findings:
The inspector sel~ted phases of the units' operation for inspectio The following are noteworthy areas:
3.3.1 Unit 1 3.3..3.2 Unit 2 Unit 1 operated at essentially full power throughout the inspection period except for short duration power reductions due to thunderstorms (to remove trip-a-unit from service and maintain system stabil-ity) and for maintenance on offsite portions of the electrical syste.3. Unit 2 operated at full power through August 5, 1987 with the exception of short duration power
- reductions due to thunderstorms, offsite electrical maintenance, or maintenance on the No. 22 steam generator feedpum.3. On August 6, 1987, a turbine trip/reactor trip occurred from 97% powe The cause of the turbine trip was a high water level in the N steam generator (SG) which was a result of operator erro At the time of the event the No. 24 SG level control system was in the manual mode of operation due to an ongoing surveillance activity on the level protection.channel which is used in the automatic control circui Based on review of post trip data, it appeared that a 5 to 7% mismatch between feedwater flow and steam flow exi~ted when the operator placed the controller in manua This condition apparently remained uncorrected for about 5 minutes until the high level turbine trip occurre Also based on post trip data, all other systems performed as designed during the even The inspector observed portions of the reactor trip recovery procedure, post trip review, SORC review of the trip cause and corrective actions, and the unit startu The unit was returned to service on August 7, 1987.
3.3..3. Later on August 7, oil sample analysis of the main power_transformers indicated that a significant breakdown in insulation had occurred in Phase A of the No. 2 main power transforme The unit was subsequently removed from service and placed in Mode 5 to support replacement of the transforme During the shutdown period, detailed containment building inspections identified a small (less than 0.4 gpm) reactor coolant leak at the base of one reactor vessel (RV) instrumentation penetration assembl These inspections were initiated due to a licensee identified increase in containment airborne activity during the period July to August, 198 The inspectors closely followed the licensee 1 s investigation and corrective actions related to the lea See Section 7 of this report for detail.3. At the close of the inspection period, Unit 2 was in Mode 5 in preparation for startup following main transformer replacement and recovery from the reactor coolant leak on the reactor vessel head.
No violations were identifie.3.3 Both Units 3.3. On ~uly 22, 1987, the units* power levels were reduced to 65% to maintain electrical grid stability due to the loss of the 500-4 transformer on the N KV line to New Freedo The transformer was re~aired that day and the units sub~equently increased to full powe.3. On July 26, 1987, lightning struck the No. 5021 500 KV line between Salem and Dean The breaker nearest the Deans line fault (2-8) did not open on the indicated fault, resulting in selective tripping
- of several other 500 KV breakers and clearing of portions of the 500 and 13 KV switch-yards. All other electrical system~ functioned as expected (i.e. fast t~ansfer of vital buses, etc.).
Load on both units was reduced to 7~% power to allow investigation of the -2-8 br~aker proble No physical component problems were identified and the 2-8 breaker tested satisfactorily.
- Licensee review of event data and breaker testing results postulated that the unusually long duration of the lightning strike (3-4 cycles) coincident with the breaker failure relay reset times for each ring bus breaker being set at 4 cycles, allowed several relays to actuat Corrective action by the licensee involved increasing the reset timer setpoints on the breakers surrounding the 2-8 breaker to 5 cycles, in order to allow greater opportunity for the 2-8 breaker to trip firs The inspector attended several licensee meetings and the SORC meeting addressing this iss0 The inspector also observed the increasing of the reset timer value No violations were identifie.3. On August 3, 1987 William T. Russell, NRC Region I Administrator, toured the Salem site with the senior resident and others of the Region* I and licensee staff The tour was conducted through the Unit 1 and 2 control rooms, switchgear and relay rooms, turbine building and auxiliary buildin A visit to the PSE&G Nuclear Training Facility was also made following the site tou.3. On August 8, 1987, the licensee discovered that the Unit 2 seal table room door was not locke This door is a normally locked administrative high radi-ation area door in that high radiation levels result when the flux thimbles are withdraw However, at the time of discovery the flux thimbles were in storage and the dose rates in the seal table room were 1 mR/hr maximum and less than 1 mR/hr general are The licensee performed the following to ensure that any possible unauthorized entries did not result in overexposures:
Reviewed records to determine that the last authorized entry was made on March 13, 198 Reviewed all Radiation Work Permits (RWP) for containment work since March 13 to verify that work was continuously covered by a health physics technicia Identified that.. some RWP's during Unit 2 forced outages in April and June, 1987 did not require continuous coverage.
Identified that routine weekly entries require continuous coverag *
Checked dose records for all personnel who had made containment entries since March 13, all were less than 1000 m It appears ~hat when the previous entry to the seal table room was made, upon exiting the door was shut but did not latc To preclude further occurrences of this type the licensee instituted shiftly checks of all locked radiation doors during outages and just prior to containment closeout following an outag The inspector reviewed completed paperwork documenting these checks and discussed this incident at length with the Radiation Protection Engineer and the Region I Radiation Specialis The inspector had no further question.3. On August 15, 1987, the security computer was out of service for approximately 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> due to the loss of it's power suppl The inspector verified that compensatory measures were performed in accordance with the security plan and that computer integrity was established by the licensee prior to its return to servic The inspector also verified that the electrical deficiency that caused the loss of the power supply has been identified and corrected by the license No violations were identifie.
Maintenance Observations The inspector reviewed the following safety related maintenance activity to verify that repairs were made in accordance with approved procedures and in compliance with NRC regulations and recognized codes and standard The inspector also verified that the replacement parts and Quality Control utilized on the repairs were in compliance with the licensee 1 s QA progra Work Order Number 870630050 Maintenance Procedure S-87-136 Description Service water pipe associated with N Component Cooling Heat Exchanger (CCHX)
The licensee identified a leak from the service water inlet pipe associated with the No. 12 CCHX on July 29, 198 This heat exchanger is a duplex design, plate type system which permits continued operations through half of the system while maintenance is conducted on the other hal An engineering evaluation (S-C-N210-MSE-0317, dated June 17, 1985) provided the necessary operating constraints (a combination of service water (SW)
temperature and flow through the CCHX) so that performance criteria assumed in the FSAR would still be met.with only one half of the component in servic The inspector reviewed the engineering evaluation and verified that the operating procedure had incorporated the required performance variables and that the system was properiy operated while the 118 11 half of the CCHX was isolat~d for the repair to the SW pip The inspector observed that a similar SW leak also existed on the outlet pipe of the 11A 11 half of the CCH This problem had also been identified by the licensee and repair was scheduled to begin after the 118
half was returned to servic The inspector was concerned that with the SW piping degraded for the 11A 11 half of the CCHX, that the engineering evaluation permitting operation of only the 11A 11 half may no longer be vali In response to this the licensee provided a safety evaluation on August 6, 1987 which justified continued operations (based on the location at the SW outlet) and provided additional, necessary guidance for the operating staff to ensure the operability of the component cooling water system under any postulated event Service water pipe degradation has been a historical problem at the Salem Statio The licensee has committed to promptly review any further identified leaks and determine the operability of the affected components by the engineering department service water task tea In
~ddition, this issue will be discussed with NRC at a management meeting which will be scheduled in the near futur No violations were identifie.
Surveillance Observations During this inspection period, the in5pector reviewed in-progress surveil-lance testing as well as completed surveillance package The inspector verified that the surveillances were performed in accordance with licensee approved procedures and NRC regulation The inspector also verified that the instruments used were within calibration tolerances and that qualified technicians performed the surveillance The following surveillances were reviewed:
Unit 1 SP(0)4.4.6.2d Reactor Coolant System - Water Inventory Balance
1--
SP(0)4.6.2.l(a)
SP(0)4.8.1. Unit 2
Containment Systems - Spray System Electrical Power Systems - Emergency Diesels
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lA Diesel for Action Statement (unloaded 15 min. run)
-
18 Diesel for Surveillance (loaded 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> run)
lC Diesel following maintenance (breaker close in)
SP(0)4.l.2.SA Reactivfty Control System - Borated Water Sources SP(0)4.1.3. Reactivity Control System - Rod Control Assemblies - done for rod 1D2 - IRPI off from step counter - recalibrated by I&C SP(0)4.0.5-V-AF-5 Inservice Test (IST) - Auxiliary Feedwater Valves SP(0)4.0.5-P-CH(21)
IST - Nos. 21 and 22 Chilled Water Pumps (22)
SP(0)4.3.2.l(E-A)
ESF - SSPS Slave Relay Test - Train A No violations were identifie.
Review of Periodic and Special Reports Upon receipt, the inspector reviewed periodic and special report The review included the following:
inclusion of information required by the NRC; test results and/or supporting information consistent with design predictions and performance specifications; planned corrective action for resolution of problems, and reportability and validity of report informatio The following periodic reports were reviewed:
Unit 1 Monthly Operating Report - July 1987 Unit 2 Monthly Operating Report - July 1987 No violations were identifie.
Reactor Vessel Head Leak Discussion and Licensee Actions During this inspection period, the licensee observed an increase in both particulate and gaseous activity inside the Salem Unit 2 containmen However, these increased activities were within accept-able operating limits, and reactor coolant system (RCS) leakage had not changed substantially from the normal *0.4 gpm value during this operating cycl The technical specification limit for unidentified RCS leakage is 1 gp During a forced shutdown due to a main trans-former problem, the licensee placed Salem Unit 2 in Mode 5 and took this opportunity to dispatch inspection teams into containment to identify 'the source of the higher containment activity (presumably reactor coolant leakage).
The team assigned to the reactor head area noticed boric acid crystals on a seam in the ventilation cowl-ing surrounding the reactor head are The licensee then removed some of the cowling and insulation, and discovered a mound of boric acid residue at one edge of the reactor vessel hea The boron crystal pile was caused by three pin hole leaks in the seal weld at the base of the No. 1 head penetration for thermocouple instru-mentation (conoseal). After cleanup of the residue, the following observations and actions were taken:
Due to the spraying of reactor coolant from the weld leak, boric acid corrosion damage was p~esent on the structural angle iron which supports the ventilation ductin The licensee subsequently replaced the affected angle iro Corrosion damage to the reactor vessel head was also present as a result of borated water dripping from the ventilation supports onto the hea The corrosion mechanism was the continuous wetting and drying of the borated reactor coolant on the hea The greatest depth of wastage on the reactor vessel head at Salem was measured at 15/32 inche The thickness of the reactor vessel head in this area is approximately 7.5 inches as measured by the license Licensee corrective actions are detailed belo The boric acid collected on the head and ran *down onto the reactor vessel head studs. The residue was collected and amounted to three quarters of a 55 gallon dru Sixteen
. studs were pulled in the area of greatest boric acid buildup, with no visual or structural damage observe One additional stud on the opposite side of the head was pulled to give a reference for visual inspectio~.
12 Inspector Observation On August 13, 1987, the inspector visually examined the reactor vessel (RPV) head and the exposed portions of the studs and nuts after the boric acid sludge (boric actd crystals and corroded steel) had been remove The head exhibited eleven areas of wastage which was caused by the corrosive effects of the boric acid solutio The affected areas ranged in length from 1/4" to
11, width froml/4" to 3/4 11 ancl_ depth from 7 /32 11 to 15/32".
The inspector did not observe any evidence of cracking in the corroded area The inspector examined the exposed portions of five reactor vessel hold down studs and nuts which were located behind the mound of boric acid sludge and found no evidence of deterioratio Evi-dence of small amounts of boric acid sludge was noted in the crevice between the stud and top f~ce o~ the nut, and between the head flange and the bottom face of the nu On August 25, 1987, the inspector reviewed documents and inspection reports relating to the licensee's response to the inciden Ultra-sonic thickness, depth measurements and magnetic particle inspection results of the corroded areas on the head were found to.be in agree-ment with the licensee's verbal repor Magnetic particle inspection was performed after the corroded areas had been flared to remove pronounced surface irregularitie The NOE report.indicated no abnormal indications* in these reactor head area The following paragraphs detail the results of the inspector's observations:
The ~ltrasonic wall thickness measurements of the areas sur-rounding the deepest corroded areas*were recorded as 7.6".
The depth of the pits as determined by a mechanical gauge ranged between l/8 11 to 15/32 11 *
In the worst case the remain-ing wall' thickness is calculated to be 7.13 11 (7.6
-
.47")
where the original design wall thickness was 7.00 11 *
Westinghouse provided an additional design analysis and indi-cated in letter no. MED-PCE-5142 that a thickness of 6.5 would satisfy ASME Code Section III requirement Westinghouse also concluded that the corroded areas had an insignificant effect on fatigue life. The inspector reviewed the magnetic particle inspection -reports for five studs (Nos. 23, 24, 25, 26 and 27)
removed from the hea No indications were reporte The licensee visually examined 12 additfonal bolts after their
_removal and found no defects as documented in deficiency
~eport SSP-87-31 The licensee furnished the inspector with a tabulation of Brinell hardness values report~d for the stud The values ranged from BHN 311 to 363 which conformed to the specifi-cation requirements of BHN 302 to 388 as specified for
Class 3 - Grade 824 SA-540 stud materia Although no exceptionaJ high hardness values were reported (greater than BHN 370) to indicate a high sensitivity to stress
- corrosion cracking (SCC) the licensee plans to closely inspect.the studs again for sec during the next outag The inspector reviewed the weld records relating to the repair of the leaking conoseal weld assembl The repair consisted of welding a new canopy seal membrane to encapsulate the original defective seal wel Welding was performed in accordance with a Tungsten Inert Gas Procedure NDWP-4 Procedure qualification and performance qualification (4 welders) were accomplished shortly before production welding using test assemblies simu-lating actual configuration and accessibilit The inspector examined the cross sectional macroscopic samples cut from the test assemblies for welding procedure and performance qualifi-cation, and found them to be acceptable in accordance with ASME III Section NB and Section IX requirement All macroscopic samples exhibited complete penetration and were found free of defect A review of NOE records for the conoseal repair weld disclosed acceptable root and final layer liquid pene-trant inspection result The records also showed that three of the remaining five conoseal seal welds.had been liquid penetrant inspected with no indications present after the leaking inciden The fourth seal weld was not liquid pene-trant inspected because of poor accessibilit Visual inspec-tion of this weld did not di~close any defect Following the completion of the weld repair, the licensee conducted an ASME Section XI hydrosiatic test to prove the integrity of the repaired conoseal wel The test was successful and no other leaks were observed in the reactor vessel head are The inspector concluded that the licensee has taken the necessary actions to justify restart. These actions included (a) modifica-tion and testing of the leaking conoseal assembly to encapsulate the defective weld, (b) inspection and analysis of the corroded head, (c) removal and inspection of 17 studs, (d) inspection of 4 remaining conoseal seal welds, (e) cleanup of the affected areas and (f) replace~ent of corroded angle iron supporting ventilation duct wor Other concerns identified during the cleanup and recovery from the conoseal leak have resulted in the following action The licensee will be meeting with Westinghouse within the next few weeks to discuss possi.bl e ways to detect reactor head leak The licensee will be meeting with Region I to discuss all followup items within the next mont *
Q
- In addition, the licensee's long term corrective actions include (a) removing and capping the present conoseal assemblies and replacing the top mounted core exit thermocouples with thermo-couples utilizing the existing bottom penetrations and incore instrumentation system; (b) consideration of modification to the ventilation shroud to incorporate inspection ports; and (c) investi-gation into the use of additional instrumentation for the detection of head leakag No violations were identifie.
Exit Interview At periodic intervals during the course of the inspection, meetings were held with senior facility management to discuss the inspection scope and finding An exit interview was held with licensee management at the end of the reporting perio The licensee did not identify 2.790 material.