IR 05000410/1987012
| ML17054C164 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 05/27/1987 |
| From: | Anderson C, Cheung L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17054C160 | List: |
| References | |
| 50-410-87-12, NUDOCS 8706100063 | |
| Download: ML17054C164 (14) | |
Text
U.S.
NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
50-410/87-12 Oocket No.
50-410 License No.
NPF-54 Category B
Licensee:
Nia ara Mohawk Power Cor oration 301 Plainfield Road S racuse New York 13212 Facility Name:
Nine Mile Point Unit No.
Inspection At:
Scriba New York Inspection Conducted:
A ri 1 6-10 1987 Inspector:
eonard Cheun
, Reactor Eng eer date Approved by:
C.
. Anderson, Chief, Plant Systems Section, EB, DRS date Ins ection Summar:
Ins ection on A ril 6-10 1987 Re ort No. 50-410/87-12 Areas Ins ected:
A routine, unannounced inspection of licensee's activities in the replacement of eight main steam isolation valves (MSIVs), covering the areas of electrical and pneumatic power supplies, MSIV trip logic, and elec-trical installation.
Results:
No violations were identified.
870b1000b3 870529 PDR ADOCK 05000410
DETAILS 1.0 Persons Contacted 1. 1 Nia ara Mohawk Power Com an NMPC
- C. Beckham, Operation QA
- W. Hansen, Manager, Nuclear QA N. Kabarwal, Electrical Engineer
"H. McCrobie, Electrical Maintenance S.
Pabby, Mechanical Engineer
- T. Perkins, General Superintendent
- D. Pike, Engineering Manager A. Pinter, Licensing Engineer
"M. Ray, Project Manager 1.2 Stone and Webster En ineerin Cor oration SWEC J. Nickols, Senior Field Engineer J.
Rogers, Nuclear Engineer M. Schi ldronth, Lead Electrical and Control Engineer 1.3 Lon Island Li ht Com an
- J. Wilson, Site Representative 1.4 New York State Power Service Commission
"P.
Eddy, Site Representative 1.5 U.S. Nuclear Re viator Commission C. Marschall, Resident Inspector
- W. Schmitt, Resident Inspector
- Denotes those present at the exit meeting on April 10, 1987.
2.0 Hain Steam Isolation Valve MSIV Re lacement NMPC is in the process of replacing the eight ball type MSIVs.
There are four inboard and four outboard valves.
The existing valves are being replaced because of problems with excessive leakage of the valves and their excessive closing time.
The new HSIVs are "Y" pattern type globe valves manufactured by Rockwell.
The following discussion describes the inspections conducted on the new MSIV.1 MSIV Actuators Each MSIV actuator consists of one dual-coil 3-way solenoid valve (for open-close operation),
one single-coil 3-way solenoid valve (for testing mode),
one two-way air operated valve (for closure ),
one 3-way air operated valve (for testing mode),
one 4-way air operated valve (for open-close operation),
and an air accumulator to supply reserve air for MSIV closure in case of air supply failure.
The, dual-coil solenoid valve is arranged so that during normal power operation, both coils are energized and the MSIV is in the open position.
Each of the dual coils is powered by a trip logic independent of the other coil.
Both coils. must be deenergized for the MSIV to close.
This allows the trip logic to be tested with-out causing the MSIV to close during normal power operation.
The MSIV is actuated by an air cylinder which provides slow opening and closing of the valve In case this fails, the loaded spring can also close the valve (fast closure),
when initiated by the containment isolation signal.
The hydraulic speed control system is provided to regulate the valve closing speed through adjustment of a hydraulic flow control valve.
The valve components and operation requirements are described in Rockwell International Report No. RAL-5293, "Instruction Manual, 26 Figure 1612 JMMNTY, Main Steam Isolation Valves for Nine Mile 2,"
dated February 26, 1987.
The inspector reviewed this report and did not identify any unacceptable conditions.
2.2 MSIV Electrical Power Su lies There are three electrical power supplies that can provide power to each of the MSIVs.
The normal source is station power.
When this becomes unavailable, battery power will be automatically connected (through Uninterruptible Power Supply 3A, B) to power the MSIV.
A third source (reserve station service) is available from the diesel generator except in the event of a LOCA.
The licensee considers the power supplies to the MSIV to be non-Class 1E, because all of the MSIVs can be closed without electrical power.
However, the control logic and all circuit devices are classified as 1E.
The inspector verified the power supply source through a review of the following SWEC drawings:
a)
12177-EE-M01E-4,
"Plant Master One Line Diagram Emergency 600V and 120VAC," Revision 4, dated February 27, 1987 b)
12177-EE-M01F-4, "Plant Master One Line Diagram Emergency and Normal 125V and 24/48VDC," Revision 4, dated January 7,
1986 c)
12177-EE-MOlC-4, "Plant Master One line Normal 600V and 120VAC,"
Revision 4, dated February 23, 1987
d)
12177-EE-M01D-6, "Plant Master One Line Diagram Normal 600V and 120VAC," Revision 6, dated February 4,
1987 e)
12177.-EE-M01B-3, "Plant Master One Line Diagram Emergency Power Distribution," Revision 3, dated February 10, 1987 f)
12177-EE-M01A-4, "Plant Master One Line Diagram Normal Power Distribution," Revision 4, dated February 10, 1987 g)
12177-EE-M01G-4,
"Plant Master One Line Diagram Normal 125VDC,"
Revision 4, dated January 7,
1986.
The uninterruptible power supplies are depicted in Figure 8.3-5 of Amendment
FSAR, entitled
"25KVA Single Phase Uninterruptible Power Supply System."
Within the scope of this review, no unacceptable conditions were identified.
2.3 Pneumatic Power Su lies The MSIVs are operated by pneumatic power supplies which move the valve air cylinder.
In the Nine Mile 2 installations, the four out-board valve actuators are connected to the instrument air supply system while the four inboard valve actuators are hooked up to the containment nitrogen supply system.
General Electric (GE) document FDDR KG1-0774, entitled "Main Steam Isolation Valve Installation Instruction," (Revision 0, dated March 5,
1987)
Paragraph VIII-1 indicates that the pneumatic pressure must be 90 to 100 psig, and the maximum pressure should be 125 psig.
The inspector reviewed SWEC flow diagrams 12177-FSK-14-1A, 1B and 1D and noticed that the maximum nitrogen supply pressure can be as high as 135 psig during normal environment.
Because there is a check valve at the inlet of the pneumatic accumulator, the nitrogen pressure can increase above 135 psig at increased ambient temperatures.
The inspector's concern is that with the nitrogen pressure higher than specified, the ASCO solenoid valves may not be able to close or open against the differential pressure.
This would affect the operation of the MSIVs.
The licensee contacted GE for the resolution of this concerns GE provided the inspector the environmental qualification test report of the MSIV actuator (NEDC 31343,
"Environmental guali-fication Test Report for Nine Mile 2 MSIV Actuator," dated March 17, 1987).
The test result demonstrated that this actuator is capable.of operating at a pressure of 185 psig.
The inspector
'had no further questions and this issue is resolve.4 MSIV Tri Lo ic Review The MSIVs are tripped (fast closure)
by the Nuclear Steam Supply Shutoff System functions when sensor signals exceed setpoints and deenergize the relay control circuits.
The control circuitry is arranged in a dual system so that a trip condition must occur in both trip systems to cause closure of the MSIVs.
Each trip system contains two independent sensors from each measured variable, only one of which is required to activate a trip system.
There are. seven monitored parameters that make up a trip logic channel for MSIV closure.
These parameters are:
reactor low-low water level, steam line high flow, main steam line low pressure, main steam line high radiation, main condenser low vacuum, turbine building high temperature, and main steam line area high temperature.
Eight control switches and various control relays were added to the control logic circuitry to modify the reset functions.
GE drawings 807E152TY, Sheets 5, 6, 10 and 11, entitled "Nuclear Steam Supply Shutoff System Elementary Diagram," Revision 24, have been revised preliminarily by the licensee to incorporate the changes.
The inspector reviewed these drawings and GE field deviation dispo-sition request FDDR-KGI-5915, Revision 0, dated February 4, 1987.
Within the scope of this review, no deficiencies were identified.
2.5 Electr ical Instal 1 ation 2.5.1 As of April 9, 1987, only a portion of electrical instal-lation had been completed.
The eight MSIV control switches were being assembled and tested in the control room area, but were not yet installed.
No new cables were pulled as existing cables are sufficient to cover the new controls.
Out of eight MSIVs, only one valve actuator (2MSS*AOV7C)
was in place.
The wiring for this actuator was not com-plete because the safety-related limit switches were not yet installed.
The inspector selected junction box 2*JB0564 for physical inspection.
This junction box contains 16 Raychem splices, all for control cables.
The inspector examined the installed conditions of these splices and did not identify any deficiencies.
2.5.2 Paragraph VIII.4 of GE document FDDR KG1-0774 indicates that the limit switches shipped with the MSIVs must be replaced with environmentally qualified NAMCO limit switches Model EA740-80120.
The top and bottom gaskets of the limit switches must be replaced with EPDM gaskets.
To ensure that these steps had been incorporated by the licensee, the inspector reviewed the licensee's Installa-tion Plan for the MSIV entitled,
"MSIV Y-Pattern Globe
Valve Installation," No.
N2Y86MÃ204LF034.
Sequence Nos.
2.4.3. 1 and 2.4.4. 1 pyescribe the steps of the limit switches and gasket replacement requirements.
Signature blocks are provided in these installation steps, requiring the installer's and the QC inspector's signatures when the installation is completed.
The licensee stated that both the limit switches and gas-kets had been received.
However, the gaskets received were the wrong size and had to be reordered from the vendor.
For the limit switches received, the licensee's QC inspectors identified various termination problems.
These problems included "wire insulation crushed on ter-minal block barriers," "wiring bent to radii less than 4,inch" and "crimps off-centered," etc.
Subsequently, N&D 17197 was generated on April 7, 1987 by the licensee.
On April 23, 1987, the inspector received a copy of the dispositioned N&D,17197.
This N&D report indicates that 44 limit switches were affected and were hand carried by Niagara Mohawk QA, SWEC and GE engineering representatives back to NAMCO for rework under the vendor's QA program.
The termination and wiring problems were corrected and the switches were hand carried back to Nine Mile 2 for installation.
These limit switches are required to perform a safety func-tion in that they send signals to the Reactor Protection System.
Per telephone conversation with the licensee on April 24, 1987, the inspector was told that SWEC is evalu-ating the reportability of this problem under
CFR 21.
They expect the evaluation to be completed in the week of April 27, 1987.
This item is unresolved pending NRC'
review of the licensee's evaluation (50-410/87-12-01).
3.0 Status of Previousl Identified Item 3. 1 (Closed)
Unresolved item 50-410/87-05-01 pertaining to potential excessive MSIV closure and unit trip during surveillance test.
The new MSIV design uses dual coil solenoid valve.
Both coils must be deenergized for the MSIV to close.
Power supply interruption to one, coil during surveillance testing will not cause the MSIV to close.
Therefore, this concern does not apply to the new MSIVs.
This item is closed.
4.0 Unresolved Items
Unresolved items are matters about which more information is required in order to ascertain whether they are acceptable items, or violations.
Unresolved items identified during this inspection are discussed in Details, Paragraph 2. pl
The inspector met with licensee and construction representatives (denoted in paragraph 1.0) at the conclusion of the inspection on April 10, 1987 at
'he construction site.
The inspector summarized the scope of the inspection, the inspection findings and confirmed with the licensee that the documents reviewed by the team did not contain any proprietary information.
The licensee agreed that the inspection report may be placed in the Public Document Room with-out prior licensee review for proprietary information (10 CFR 2.790).
At no time during this inspection was written material provided to the license I