IR 05000412/1986033
| ML20207J160 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/22/1986 |
| From: | Gregg H, Strosnider J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20207J128 | List: |
| References | |
| 50-412-86-33, IEIN-86-005, IEIN-86-5, NUDOCS 8701080320 | |
| Download: ML20207J160 (7) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
50-412/86-33 Docket No.
50-412 License No. CPPR-105 Category B
Licensee: Duquesne Light Company
- _.0TBox4 Ibippingport, Pennsylvania 15077 Facility Name: Beaver Valley power Station, Unit 2 Inspection At: Shipppgport, pennsylvania Inspection Conducted: October 20-24, 1986
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Inspectors 1A4
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Td i. I. Gregg, Lead Reactor lineer
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Approved by:
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NAA/W (<t
. Stfosn~1derTCril
, haterial & Processes date Section, Engineering Branch, DRS Inspection Summa _ry:.!_nspection on October 20-24, 1986 (Report No. 50-412/86-33 r
n Areas Inspected: A routine unannounced inspection of licensee's activities related to the new ball type Main Steam Isolation valve (MSIV) operability problems and the Main Steam Safety Valve (MSSV) improper ring setting problems was conducted. These issues have been reported by the licensee through Construction Deficiency reports and were the subject of a prior Region !
inspection.
Results:
No violations were identified, however, the Itcensee's final course iif action regarding the two problem areas are not in place ind the current unresolved items remain open.
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DETAILS 1.0 Person Contacted 1.1 Duquesne Light Company (DLC)
J. Carey, Vice President Nuclear Group
- A. Crevasse, Dep. QA Mgr
- F. Curl, PTO Mgr T. Francis, Proj. Mgr Schneider Corp (under DLC contract)
- J. Godliski. Senior Test Engineer
- D. Hunkele, Dir. QA Ops.
"J. Jaworski, Senior Engineer
- J. Johns, Supervisor QA Surveillance
- J. Kline, Mgr BV2 Engrg & Construction
- D. Rohm, Assist. Director QC
- C, SIlfkin, BOP Superv, of Testing
- R. Swiderski, Startup Mgr J. Thomas, Project Engineering Mgr, Unit 2
- R. Wa11aner, Lead CompItance Engr I
- L. W1111ams, Dir. Start Up M. Zakt, Lead Mech. Engr.
'G. Zosack, Compliance Engr.
J. Steinke, Test Engineer 1.2 Stone and Webster Engineering Company (SWEC)
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- H. Durkin, Site Officer Engrg.
- H. Foley, Site Proj. Mgr.
- D. Lessard, Assist. Supt. Engrg.
M. Lynch, Principal Power Engr.
- R. Wittschen, Licensing Engr.
1.3 U.S. Nuclear _ Regulatory Commission _(NRC)
- A. Asars, Resident Inspector
- J. Beall, Senior Resident Inspector
- L. Tripp, Section Chief, RI
- Denotes those present at exit meeting.
2.0 MainSteamIsolationValve_(MSIVsl 2.1, Background Review Beaver Valley Unit 2 (BV-2) is one of two plants in the USA, scheduled to go operational in the near future, that will utilize a new ball type MSIV.
The other plant is Nine Mile Point 2 (NMP-2).
As the plants approach operational status MS!V preoperation testing is performed to verify operational capability of the valve.
The results of this testing at NMP-2, the plant in the more advanced test i
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stage, have revealed significant problems with the valve internals and the valve actuating mechanism (see NRC Inspection Reports 50-410/86-53 and 86-67).
BV-2 made a Construction Deficiency Report (COR 86-00-02) to the NRC relating to the actuator latching problem. Also, a prior NRC Inspection Report included an Unresolved Item (UNR 84-16-04) concern-ing repairs to the BV-2 valve body seat spool bore and the subsequent inability to achieve the 4.8 SCFH seat leakage criterion for the between the seat leak test.
Several Region I inspection reports provided updates on these problems and to dato neither of the above issues has been closed.
The BV-2 MSIVs are important safety category equipment and are required by technical specifications to close within b seconds. Correction of problems with valve internals and the actuator are essential for adequate valve operation.
The following additional background information was obtained.
- The 24" ball type MSIVs were analytically extended from an 8" valve design. A full size 24" valve wasn't tested and there was no field experience.
The only US plants with these valves are NMP-2 and BV-2.
- There is only one grinding machine in the US with capability for this size ball 4.nd the vendors entire facility is presently being used for the NMP-2 work.
- NMP-2 has performed extensive in-situ repairs and testing, and has made prototype test valve commitments.
The vendor is also
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working closely with NMP-2.
BV-2 is aware of the NMP-2 efforts.
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2.2 Inspection Findings
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2.2.1 Review of Action Plans The inspector reviewed actions taken by the licensee and the licensee's plans to address the MSIV problems.
The service requirements for these valves also were reviewed. Observations were made of the valve disassembly and several of the valve internals. Datorminations made by the inspector were as follows.
- BV-2 has formulated three preliminary attornative plans:
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Perform design corrective actions on the ball valve
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internals and the mechanical latch arrangement i
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Pursuo use of the hydraulic actuator system for closing the ball valves
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Change to a different type of valvo
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The licensee wants to make use of as much NMP-2 experience as possible prior to selecting a final action plan. A final plan has not been selected to date.
The licensee's management wants to pursue the mechanical
latch arrangement and is planning an actuator test program.
- BV-2 is aware of the NMP-2 problems and corrective actions (the ball wear, changing the seat spring arrangement, thrust l
washer material change, and the use of the hydraulic system
replacement of the mechanical latch).
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The MSIVs at BV-2 have had fewer cycles than the NMP-2 valves.
- Because of the NMP-2 problems, BV-2 was not performing any additional MSIV cycling to prevent any further damage to their MSIVs o
2.2.2 Observations of Valves and Parts A decision to disassemble the MSIVs was made during this inspection.
The inspector was able to observe the disassembly and observe several of the internal parts. Determinations made by the inspector were as follows.
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The actuator removal utilized four (4) chain hoists (one at each corner) and was extremely effective.
The bonnets l
and internals were removed without difficulty.
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The ball was removed from the "B" valve allowing examination
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the valve ball.
Both the seats and the ball were in good I
condition.
The inlet seat from valve "C" (still inside valve) had a
slight sharp I,0, edge at the seat to ball high loading point (the location where the seat becomes unstable when eclipsing port).
The "C" ball had scoring through the tungsten carbide coating at the corresponding location near
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the open port (only one side of the ball could be viewed).
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The scoring was not as extensive as that seen on the NMP-2 valves, however, these valves have had fewer opening and closing cycles than the NMP-2 valves.
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- One of the valves did exhibit galling of the thrust washer but not to the extent of NMP-2 valves.
BV-2 was aware of the change to a bronze thrust washer at NMP-2, 2.2.3 Question Concerning Weld Material Overlay on the Ball During discussions with the SWEC personnel, the weld overlay on the ball was described as Stellite 6 (the overlay beneath the tungsten carbide spray coating). A Bill of Material No.1798N that had a notation of Stellite 6 on the ball was provided to the inspector. No further documentation (i.e. weld rod type or weld procedure) of the type of weld material could be found.
The vendors topical report specifies the NMP-2 valves have a Haynes 25 weld overlay.
If the material beneath the tungsten carbide is Stellite 6, a recognized valve seating material, other alternatives for valve modification or repair could exist.
The licensee was going to obtain verification of the ball weld overlay material.
The inspector also observed the spare ball and two spare seat rings in the storeroom.
The documentation for this ball men-tioned tungsten carbide but there was no mention of any weld material overlay.
The Itcensee also was going to determine if the spare ball had a weld overlay (one of the NMP-2 balls had only the tungsten carbide coating).
2.3 MS_IV Conclusions Both of the following items remain open pending the licensee's imple-mentation and NRC verification of corrective action that assures adequate operational capability of the new ball type MSIVs. The inspection details of this report are an update of the following open items.
(0 pen)UNR 84-16-04 Repair of MSIVs (0 pen)CDR 85-00-02 Actuator Latching Problems Based on experience at NMP-2 and BV-2, the new ball valve MSIVs have internal design problems and actuator design problems. Corrective actions with valve internals and the actuator and verification of adequate operational capability are required in each of these areas.
At the time of the inspection exit, the licensee had not finalized an action plan for repair of the MSIV interna.s or actuato.
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l 3.0 Main Steam Safety Valves (MSSVs)
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3.1 Background Review A recent IE Information Notice (IEN 86-05) advised licensees of the possibility that their MSSV ring settings may not be correct.
Improper ring settings can result in less than full lift and less than required steam flow relieving capacity.
During a prior Region I inspection it was determined that the Beaver i
Valley 2 MSSV ring settings may not be correct (see Inspection Report
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50-412/86-05).
Improper ring settings can result in less than full lift and less than required steam flow relieving capacity.
It was determined that the BV-2 ring settings were not the vendor's recommended ring settings. The issue was left as an Unresolved Item (UNR 86-19-01)
pending the licensee's implementation of corrective actions to assure proper MSSV ring settings.
3.2 Current Inspection MSSV Findings l
A review of the licensee's actions taken to date and plans to address l
the MSSV ring setting problem was performed and the inspector obtained the following information.
- The licensee is a Westinghouse Owners Group (WOG) participant and has provided input to the WOG test plan, c
The finalized WOG test plan is scheduled to be sent to the plants by October 24, 1986 for approval.
- BV-2 will accept the WOG test plan if the BV-2 valves are tested early enough in the program.
BV-2 will require the correct ring setting information to be made available to them
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by February 1987.
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Final BV-2 actions to correct ring settings is intended prior to fuel load (ring setting activity will also require set point i
adjustment). Corrective action will be taken even if WOG program is not utilized.
- Formal documentation of the above actions to be taken, was not in place.
During discussions regarding the problem, the licensee's personnel pointed out that set point testing would be performed within the startup testing program.
The inspector made it clear that set point testing (valve opening point), does not resolve the ring setting problems (valve lif t, capacity and blowdown).
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3.3 MSSV Conclusions The following unresolved item remains open pending the licensee's implementation and NRC verification of corrective actions that assure proper ring settings.
(Open) UNR 86-19-01 MSSV Improper Ring Settings
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The inspection details of this report are an update of the above unresolved item.
4.0 Exit Meeting The inspector met with the licensee's representatives (identified in paragraph 1.0) at the conclusion of the inspection on October 24, 1986 to summarize the findings of the inspection. The NRC Resident Inspectors, J. Beall and A. Asars were also in attendance.
During this inspection, the inspector did not provide any written material to the licensee.
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