IR 05000245/1986007
| ML20210V513 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/27/1986 |
| From: | Mccabe E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20210V493 | List: |
| References | |
| 50-245-86-07, 50-245-86-7, 50-336-86-07, 50-336-86-7, NUDOCS 8606100649 | |
| Download: ML20210V513 (11) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report:
50-245/86-07; 50-336/86-07 Docket Nos:
50-245/50-336 License Nos. DPR-21; DPR-65 Licensee:
Northeast Nuclear Energy Company Facility:
Millstone Nuclear Power Station, Waterford, Connecticut Inspection at: Millstone Units 1 & 2 Dates:
April 8, 1986 through May 19, 1986 Inspectors:
Theodore A. Rebelowski, Senior Resident Inspector Geoffrey E. Grant, Resident Inspector Approved:
0W brhd 27 8S r,
E.C.McCabe, Chief, Reactor /rojectsSection3B Date Summary:
50-245/86-07; 50-336/86-07 (April 8 to May 19, 1986)
Scope: Routine NRC resident inspection (196 hours0.00227 days <br />0.0544 hours <br />3.240741e-4 weeks <br />7.4578e-5 months <br />) of plant operations, surveillance, maintenance, 10 year containment tendon surveillance (Unit 2),
scram instrument volume level switch torquing (Unit 1), potential steam binding of auxiliary feedwater pumps (Unit 2); design changes, snubber training, spent fuel pool reracking (Unit 2), diver out of authorized area (Unit 2), main turbine inspection planning (Unit 1 & 2)~, standby liquid control system lineup (Unit 1), and unresolved items.
Results: No unacceptable conditions were identified. A need for ongoing careful control of divers in the spent fuel pool was identified when a diver came closer than is authorized to irradiated fuel.
8606100649 e60530 PDR ADOCK 05000245 Q
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TABLE OF CONTENTS 1.
S umma ry o f Fa c i l i ty Acti v i ti e s....................................
2.
Plant Operational Safety Veri fication.............................
3.
10-Year Containment Tendon Surveillance (Unit 2)..................
4.
Scram Instrument Volume Level-Switch Torquing (Unit 1)............
5.
Potential Steam Binding of Auxiliary Feedpumps (Unit 2)...........
6.
Planned Plant Design Changes (Unit 2).............................
7.
Snubber Training (Units 1 & 2)....................................
8.
Maintenance (Units 1 and 2).......................................
9.
Uni t 2 Spent Fuel Pool Re racki ng.................................. 6 10.
Diver Out of Authorized Diving Area (Unit 2)...................... 6 11.
Fi re Damp e r s ( Un i t 2)............................................. 8 12.
Main Turbine Inspection (Units 1 and 2)...........................
13.
Standby Liquid Control System (Unit 1)............................ 8 14.
Unresolved and Other Items Involving Licensee Action.............. 9 15.
Management Meeting................................................
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DETAILS 1.
Summary of Facility Activities Unit 1 Unit 1 operated at 100% power except for minor power reductions for surveillance testing and condenser tube plugging.
Unit 2 Unit 2 operated at 100% power except for minor power reductions for surveillance testing and condenser tube plugging. The spent fuel pool (SFP) fuel shuffle was completed for SFP Region 1 and 2 fuel racks N7, 8, and 9.
2.
Plant Operational Safety Verification Licensee management controls were observed to assess whether the facility is being safely operated in conformance with NRC requirements.
Findings were based on interviews and discussions with licensee personnel, ficility tours, observation of selected activities, and inspector checks of selected safety system status.
2.1 Control Room Activities (Unit 1 & 2)
Control room activities were observed during daily checks and backshift visits. During shift changes, it was noted that information to the oncoming shift included discussion of out-of service equipment, ongoing surveillance testing, review of leak rate data, control board walkdown, and forthcoming evolutions such as diesel fuel deliveries and rod pattern adjustments.
It was found that the information interchange between operators, senior operators, and shift supervisors was proper.
2.2 Operability of Engineered Safeguard Features Unit 1 - The inspector verified valve, instrument, and electric power lineup on the standby Liquid Control System and the "A" Low Pressure Injection system.
No anomalies were identified.
Unit 2 - The inspectors verified the standby status of the "B" emergency diesel in regard to lubrication, cooling, fuel avail-ability, and air start.
No anomalies were identifie.
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2.3 Tours of Facilities (Unit 1 & 2).
Tours of accessible areas were routinely performed.
Exterior areas, including security fencing, were also toured. Assessments of equipment condition, radiological controls, security, and safety were made. Both units were notably absent of valve packing leaks. No fire hazards were observed. No unacceptable conditions were found.
2.4 Radiation Protection Control The inspe-tor found that radiation surveys were made during all routine maintenance and surveillances, and that proper barriers and radiation work permits (RWPs) were in view. Observations were made of Health Physics monitoring of and instructions to plant personnel and contractors on area radiation conditions. No anomalies were identified.
3.
Ten-Year Containment Tendon Surveillance - Unit 2 In-service tendon surveillance consists of evaluating the condition of the tendons, determining lift-off forces for selected tendons, and determining the effectiveness of the corrosion protection system. The first two of these activities were observed and reported on in Inspection Report (IR) 50-336/86-03.
Corrosion protection was observed during this reporting period.
The surveillance involves inspecting the corrosion inhibiting system installed in the sheaths of the post-tensioning system.
That includes examining the sheathing filler (a special grcase) for 16 below grade horizontal tendons for water entry.
The inspectors observed sheathing filler removal and installation of new filler, including the following:
- Equipment set-up for filler material removal.
- Purge air moisture content control.
- Operator communications.
- Compliance with PORC approved surveillance procedures.
- Pre-heating control of the new filler material.
- Old filler material discha ge effluent inspection.
Several of the inspected tendons contained free water or moisture entrained in the filler material.
By procedure, this finding required the inspection of an additional eight tendons for moisture. None of these additional tendons contained evidence of water intrusion.
Samples of filler material from all inspected tendons are to undergo laboratory analysis to determine the concentrations of water, chlorides, sulfides, and nitrates.
The analysis results are to be included in the final surveillance report. Also, by procedure, one wiro is to be removed from tendon 12H04 due to the several gallons of free water found. This wire will undergo the same laboratory analysis as the three wires removed for surveillance as reported in IR 86-03.
These analyses will be subject to NRC review as the information becomes availabl.
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The licensee has designed and installed a special tendon pressurizing system to limit moisture intrusion in below grade tendons.
This system uses air pressurized filler connected to tendon grease caps to provide a positive pressure inside the tendon sheath.
The system is to be implemented shortly after completion of tendon surveillance.
No tendon surveillance deficiencies were identified.
4.
10 CFR 21 Scram Instrument Volume Level Switch Torquing - Unit 1 In late April the licensee received notification of a 10 CFR 21 report submitted by Magnetrol International on Nuclear Safety-Related Model 402 Level Switches.
This equipment was supplied without a torque check of the switch enclosing-tube nut.
The nut should be torqued to 200 to 225 ft-lbs. The notification asked the licensee to torque check all such level switches. At Unit 1, these switches are used in the Control Rod Drive System to sense liquid level in the Scram Instrument Volume.
There are six switches per volume with one switch providing a high level alarm, one providing a high level rod block, and four providing a high-high level scram signal to the Reactor Protection System.
The resident inspectors observed the torquing and retest operations performed by the licensee. Aspects observed included:
- Torquing and testing documentation.
- Determination of as-found switch level setpoints (these were all acceptable).
- Determination of as-found enclosing-tube nut torque values (many of these were low).
- Enclosing-tube nut torquing operations.
- Determination of post-torque switch level setpoints.
- System restoration.
The procedure used to accomplish the operation was well thought-out.
Personnel involved were pre-briefed. A mock-up (a spare level switch)
was used to prepare for the operation. The normal surveillance procedure was conducted af ter system restoration to ensure proper operation. That surveillance will be conducted one week after completion of torquing to assess continued normal system operation and then will revert to the normal surveillance schedule. No unacceptable conditions were identified.
5.
NRC Bulletin 85-01, Steam Binding of Auxiliary Feedwater Pumps - Unit 2 NRC Bulletin 85-01 addresses the loss of auxiliary feedwater (AFW) due to steam binding of Auxiliary Feed Pumps caused by hot water leaking from the steam generators back to the pumps.
The licensee's response letter is dated 2/28/8 L
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5.1.
The licensee has changed the Plant Equipment Operator (PE0) Logs to require a check of the AFW discharge piping temperature each shift.
If the pipe is above ambient temperature, the shift supervisor is notified.
Inspector review of the PE0 legs showed that these checks have been made with no above ambient temperatures identified.
5.2.
The licensee has changed procedure OP2322, Auxiliary Feedwater System, Rev. 9, Change 1 to add a new section 7.10,
" Steam Binding of Auxiliary Feedwater Pumps." The section identifies actions that Shift Supervisors must implement to ensure operability of pumps and prevent steam binding.
These include the following:
- Redetermine temperature by hand pyrometer.
- If pump and discharge piping is below 185 degrees but hot to the touch, operate pump (s) for 15' minutes or recirculate.
- Check for backflow.
- For temperature greater than 185 degrees - secure the discharge valve of the affected AFW pump. A Limiting Condition for Operation (LCO) is involved and is noted in the procedure.
(T.S. 3.7.1.2 requires 3 operational AFW pumps.)
- Open pump casing and vent.
- Run pump for 15 minutes on recirculation.
- Realign valving and run pumps for approximately five minutes to the Steam Generator.
- Investigate leak.
5.3.
The licensee has committed to keep these procedural controls in effect pending resolution of Generic Issue 93, Steam Binding of Auxiliary Feedpumps. That resolution is presently scheduled for completion in by September 1987.
No deficiencies were identified in the licensee response to Bulletin 85-01. This item is closed.
6.
Review of Plant Design Change Requests - Unit 2 The inspector attended a planning meeting for the Unit 2 September 1986 outage. Planned activities include changeout of the main condenser tube sheets and tubes.
The licensee was presented with a preliminary design change review by corporate engineering, who discussed removing the present condenser tubes and sheets, and replacement with preassembled titanium tubes and tube sheets.
Some items discussed were removal of parts of the turbine building wall; placing additional tracks to carry the new assemblies; reinforcement of feedwater heaters internal to the condensers; decontaminating and preparing removed tubes for offsite burial; and cathodic protection system.
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During this changeover, the licensee will place the main circulating water system out of service. This system dilutes radioactive liquid discharges. Acceptability of discharge concentrations during the condenser tube changeout will be examined through routine inspection.
No unacceptable conditions were identified during this inspection.
7.
Snubber Training During a site tour, the inspector observed training at the snubber test facility at Unit 2.
Four licensee technicians (trainees), a licensee instructor, and two vendor representatives were participating in hands-on orientation. The trainees were from each of the three Millstone Units and Haddam Neck. They had completed classroom training which included review of hydraulic principles and test equipment training which included the use of procedures to document snubber test results.
Snubbers under test included ones which may be used as replacements during the Unit 2 outage.
Licensee QC checks were made and documented for safety system snubbers.
No inadequacies were noted.
8.
Monthly Observation of liaintenance Control Rod Scram Solenoid Valve Maintenance - Unit 1 The licensee's reliability assurance program for Control Rod Scram Solenoid Valves involves cleaning and parts replacement. The inspector witnessed the associated disassembly and reassembly of Control Rod Drive 50-31.
The material replacement kit had an expiration date of 2/87.
Procedures involved were Operating Procedure 302-19 Rev. 16, Maintenance Procedure 703.7, and Plant Procedure Maintenance System (AWO) Procedure M186-292. These procedures were at the work site. A radiation permit (RWP 00902) was issued to control the work area. During this maintenance, the Control Rod was required to be fully inserted.
That was done.
Reactor engineering was notified prior to the start of work and verified that the reactivity change would not affect operations. A minimum change in reactivity was noted (only the edge rods are being upgraded under this program during power operation). Cooling flow to the control rod was maintained. The work received QC coverage, with verification of key parameters. NRC inspector observations included the radiation survey, "0" ring removal and replacement, and diaphragm change.
Retesting was accomplished satisfactorily upon completion of work. Also noted was double verification of valve lineups.
No unacceptable conditions were observed.
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Diesel Maintenance - Unit 2 Observation of corrective and preventive maintenance on the "A" Diesel Generator was observed. The maintenance was primarily correction of several small fuel leaks, repair of a leaking lube oil cooler mechanical joint, and replacement of an air coepressor dryer pre-filter assembly.
The inspector-also reviewed the work package documentation.
Discussions with maintenance personnel revealed that they had a high level of knowledge about the current maintenance and about general diesel generator maintenance issues. The observed level of involvement of licensee quality control personnel was found to be consistent with the maintenance.
No unacceptable conditions were observed.
9.
Spent Fuel Pool (SFP) Rerack Activities - Unit 2 The SFP Rerack Program is discussed in NRC IR 50-336/86-03. As of the end of the current report period, all old fuel racks have been removed and cleaned, and all but three racks have been shipped to Quadrex Corp.
in Tennessee. The remaining racks are oversized for shipment and were discussed by the licensee with the State of Connecticut on May 16, 1986, with plans made for shipment in late May 1986. The inspector witnessed licensee surveys of shipping packages on a sampling basis and identified t
no inadequacies.
All spent fuel previously stored in the old racks has been placed in new SFP Region 1 and 2 racks. Additional fuel in the transfer area is to be placed in Region 1 racks upon completion of new rack installation.
Prior to the transfer of spent fuel assemblies to SFP racks 7, 8, and 9, the inspector witnessed testing of the fuel transfer tool with a dummy assembly.
Placement of the dummy assembly in various racks was satisfactory. The load cell showed entry, bottoming, and lift loads as required. The inspector also found that procedures were at work stations and personnel were knowledgeable of actions to be taken to complete testing.
Proper protective clothing for access to the SFP bridge crane was in use.
The inspector had no further questions.
10.
Diver Out of Authorized Diving Area The licensee's procedure for " Divers in Spent Fuel Pool" requires constant surveillance of divers in the pool.
On April 18, at 0950, a diver entered an area that was within seven feet of spent fuel.
No overexposure resulted.
The diver was searching for a missing part from a vacuum cleaning system used to clarify water after removal of flooring steel from removed spent fuel racks. Nets (cargo type, with about 1 square foot openings) are installed to maintain a minimum working distance of seven (7) feet from spent fuel.
The diver propelled himself into a net and came to within 2'- 4' from and 2'- 3' above spent fuel assembly storage.
Survey dose rates in this area indicated an 800 - 1100 mrem /hr zone.
The alarming dose rate meter on the diver's suit alarmed and indicated a 200-300 mrem /hr field.
The Health Physics (HP)
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Technician and diver tender respended to the alarm.
However, the diver tender's retrieval action entangled the diver in the cargo net. The diver freed himself and was brought to the surface. His approximate time in the unauthorized area was jydged to be 15 seconds.
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10.1 Licensee Action and Investigation All diver's work was halted by thy HP Department.
The SFP di.ving radiation work permit (RWP) was suspended pending completion of the investigation. Management was notified.
Processing of the diver's TLD packets showed a 25 mrem exposure. The area was resurveyed to check the previous radiatien survey, An investigative. meeting was hald. A contri-buting cause was determined to be failure to sectre the cargo nets to
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prevent billowing.
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10.2 Corrective Action 10.2.1 The licensee decided to stiffen the nets by either using stanchior,s or securing the net bottoms and increasing the tensicn on the nets. All net installetions he to incorporate stiffening.
The inspector venfied that this action was taken by observuton of the SFP on May I').
10.2.2 As before, the diver tender is to maintain constant visual surveillance on the diver.
The tender now has connunications to the diver,. is to instruct the diver on his position relative to the 7-foot line, and is responsible for keeping the diver in the authorized work area. Health Physics (HP) is to work with the tender to ensure the diver stays in the destgrated,vork area.
The inspector observed divers in the pool after diving was again authorized. Tend 6r and HP nonitoring was being performed as prescribed.
10.2.3 The incident and the corrective actions are to be reviewed with all divers and Health Physics Technicians.
That review is to include a
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discussion of the radiation ha:ards and risks associated with spent fuel.
Inspector review of associated documentation found it satisfactory.
10.3 Additional Corrective Actions The Radiation Protection Supervisor instructed HP personnel to ensure that each diver is wearing an alarming dose rate meter.
The meter alarm played an important part in the immediate response to the diver's entry into the 7-foot zone.
10.4 Inspection Conclusions No unacceptable conditions were identified.
In this case, the diver received a minor but unnecessary exposure.
The inspector concluded that licensee corrective actions are acceptable and that continued careful attention to control of divers is essential to proper control of diver
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11.
Fire Damper Review - (Unit 2)
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Licensee consultants reviewed fire dampers at Unit 2 from May 12-15.
Based on preliminary findings, the licensee declared themselves in the
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Limiting Condition of Operation of fire barrier Technical Specification 3/4.7.10 on May 16 at 12:30 p.m.
This was based on 22 safety-related dampers being identified as problems.
Ten of these are improperly installed (improper expansion tolerances, inadequate distance from bulkheads,etc.) Nine others do not meet their 3-hour fire rating.
Three other dampers are missing where duct goes through a barrier.
Surveillances were reviewed to verify conformance with Technical Snecifications, and a fire watch was placed on tour. That fire watch was established with a defined tour of the 12 areas in which the 22 damper anomalies have been identified. The inspector toured these areas with the fire watch and engineering personnel at 2:30 p.m., May 16.
No
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unsatisfactory conditions were found in fire watch knowledge or area cleanliness. Damper repairs are tentatively scheduled for the first outage of sufficient duration af ter receipt of replacement dampers. The inspector had no further questions on this item, which will be rechecked during routine inspection.
12. Main Turbine Inspection (Unit I and 2)
On April 3, a letter from the main turbine generator vendor (General Electric) informed the licensee about a failed Ifurbine generator at another facility.
That event involved failure of turbine buckets at their dovetails, cracks on the wheel holding the failed buckets, and alternator failure from cyclic fatigue. Because of similarities to the Millstone 1 and 2 turbine generators, the vendor recommended ultrasonic testing (UT) of the main turbines' last stage buckets' dovetail fingers and torsional vibration testing for similar torsional resonant frequencies. On May 9,1986 the vendor identified that another similar unit had higher than expected bucket deflection at the generator end of a icw pressure rotor.
The licensee scheduled testing that includes a May 21, 1986 shutdown of Millstone 1 for seven days. UT is to be performed then, with shaft torsional testing to be done in August 1986. Millstone 2 is to be shutdown for UT after Millstone 1 returns to power. As of May 19, Units 1 and 2 had been on line for 101 and 197 days, respectively.
Inspector review identified no unacceptable conditions in the licensee's plans. UT testing will be included in routine inspection coverage.
13.
Standby Liquid Control System - (SBLCS)-Unit 1 Reference; NUSCO PID 29129.
The Standby Liquid Control System (SBLCS) is a backup system for shutting down the reactor.
The system injects a neutron absorbing solutio _ _ - - _.
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The inspector walked down accessible piping and fcund that:
- valve alignment was correct;
- instrumentation was caliorated;
- there were no unidentified leaks from valves or piping;
- liquid solution was at the prescribad temperature;
-- the Technical Specification on sodium pentaborate concentration / volume was met.
The inspector also found that the system, piping, pumps, test tanks, air agitation system, and demineralizer water system were well marked and properly tagged, and that the gensral area was clean. One minor concern was identified. The method of securing valves 1-SL-31 and -32 to their supports appears to place then in tension with main system piping.
The licensee will address this item. The insp>ctor.had no fu.ther questions at this time, 14. Onresolved_Ign3
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No uoresolved items were identified.
15. Managecont Meetings At periodic intervals during this inspection, maetings were held with senior plant management to discuss the findings.
No proprietary information was identified as being in the inspection coverage. No written material was provided to the licensee by the inspector.
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