ML20215K872
| ML20215K872 | |
| Person / Time | |
|---|---|
| Site: | Harris, Brunswick, Robinson, 05000000 |
| Issue date: | 09/19/1986 |
| From: | Zimmerman S CAROLINA POWER & LIGHT CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEIN-86-003, IEIN-86-3, NLS-86-334, NUDOCS 8610280341 | |
| Download: ML20215K872 (8) | |
Text
_- _ - _____ _
o CD&L Carolina Power & Light Company SERIAL: NLS-86-334 SEP 191986
-r F < / <'
L y K1 Dr. J. Nelson Grace, Regional Administrator
/g-United States Nuclear Regulatory Commission Suite 2900 101 Marietta Street, TU Atlanta, GA 30303 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400 UNIT NO. 1 BRUNSUICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 H.
B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET No. 50-261/ LICENSE NO. DPR-23 ENVIRONMENTAL QUALIFICATION OF LIMITORQUE VALVE ACTUATOR WIRING
Dear Dr. Grace:
This letter de.cuments telephone conversations between your staff and Carolina Power & Light Company (CP&L) held on August 21 and 25, 1986.
The telephone conversations were. held at the request of your staff to discuss the concerns identified in IE Enformation Notice (IEN) 86-03 relating to potential deficiencies in environmental qualification of Limitorque valve actuator wiring.
The discussions included the applicability of IEN 86-03~to Shearon Harris Nuclear Power Plant (SHNPP), Brunswick Steam Electric Plant (BSEP),
Unit Nos. I and 2, and H.
B.
Robinson Steam Electric Plant (HBR), Unit No.
2.
CP&L's review of the concerns in IEN 86-03 can be classified as generic and plant specific.
The generic evaluation was performed by the corporate engineering organization (the Nuclear Engineering & Licensing Department) and included the participation in the activities of the Nuclear Utility Group on Equipment Qualification (NUGEQ).
As a member of the Working Committee of the NUGEQ, CP&L was an active participant in the NUGEQ investigation and evaluation of the Limitorque motor-valve operator wiring issue.
The information resulting from this effort was utilized in the evaluation of plant-specific concerns.
Attachment I to this letter contains details of the generic activities, and Attachment 11 contains details of the plant-specific reviews.
The information presented in this letter provides reasonable assurance that the jumper and control wiring in Limitorque actuators at CP&L's nuclear facilities are qualified and that the necessary actions have been taken to resolve the concerns raised by IEN 86-03.
8610280341 860919 PDR ADOCK 0D000261 G
PDR 411 Fayetteville Street
- P O Box 1551
- Raleign. N C 27602 A-m;;1ggyugmmi
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Dr. J. Nelson Crace NLS-86-334 / Page 2 1
If you have any questions, please contact Mr. Pedro Salas at (919) 836-8015.
Yours very truly, S.
. Zi erman ger Nuclear Licensing Section PS/pgp (4074PSA)
Attachments cc:
Mr. B. C. Buckley (NRC)
Mr. W. H. Ruland (NRC-BNP)
Mr H. R. Denton (NRC)
Mr. G. Requa (NRC)
Mr. C. F. Maxwell (NRC-SHNPP)
Mr. H. Krug (NRC Resident Mr. D. Muller (NRC)
Inspector - RNP)
Mr. E. Sylvester (NRC)
ATTACHMENT I CP&L CORPORATE EVALUATION OF THE CONCERNS IN IEN 86-03 On January 14, 1986, the NRC issued IEN 86-03 which raised concerns regarding the environmental qualification of wires in Limitorque valve actuators. The notice identified as an issue the qualification of wires installed by parties other than Limitorque.
IEN 86-03 states:
Limitorque has installed wires from several different manufacturers in safety-related operators.
Limitorque has stated that it can provide or reference documentation to support qualification of wires it has installed; however, valve manufacturers, licensees, and/or others may have added additional wires that are not qualified by the Limitorque tests.
Due to the widespread use of Linitorque actuators and the potential for a generic problem, the NUGEQ looked at the issue for further investigation.
Verbal discussions between the NUGEQ and Limitorque indicated that the issue was limited to actuator control wiring only. Limitorque indicated that the wiring types used for this application were:
Raychen Flamtrol, Rockbestos Firewall III, and wire specified as Canadian Standards Association (CSA) Type TEW, which is PVC insulated. The NUGEQ prepared for its members a package with qualification data and reports to assist in the qualification of these types of wires.
The Group met on March 18, 1986 with Limitorque to discuss, among other things, the wire issue. As a member of the NUGEQ Working Committee, CP&L participated in this discussion. Limitorque confirmed that the information previously provided to the NUGEQ was correct (i.e., Limitorque has used Raychem Flantrol, Rockbestos Firewall III, and wire specified as Canadian Standards Association (CSA) Type TWE switch compartment jumper and control circuit wiring).
The information was transmitted to NUGEQ members on May 12, 1986.
This information provided reasonable assurance that wires installed by Limitorque were already qualified by existing plant-specific qualification reports or could be qualified through the data contained in the NUGEQ information or data available from other sources.
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ATTACHMENT II CP&L PLANT-SPECIFIC EVALUATIONS OF THE CONCERNS IN IEN 86-03 This attachment provides a description of the plant-specific activities performed at CP&L's three nuclear facilities.
1)
Shearon Harris Nuclear Power Plant To provide assurance of environmental qualification, CP&L has performed a 100 percent inspection of the Limitorque valve actuators (24 actuators) located in the Containment Building and in the Steam Tunnel. These are the only two areas which would be exposed to severe temperature conditions in case of an accident. The inspections have been completed. Two actuators were found to have unidentified wire which was replaced with qualified wire.
2)
Brunswick Steam Electric Plant Following the issuance of IEN 86-03 and based on the information obtained f rom the NUGEQ (see Attachment I), CP&L reviewed applicable on-site documentation to support the qualification of the various types of wire that could have been installed within BSEP actuators. Generic qualification data packages (QDPs) have been prepared for Raychem Flamtrol
[QDP-9 and 10] and Rockbestos Firewall III (QDP-12], which support Category 1 qualification for the 40-year installed life for applicable plant locations (i.e., Drywell and Reactor Building locations).
PVC Wire was qualified per QDP-67 for use within motor control centers installed in Reactor Building Elevations 20 feet and above; additional information (pertaining to PVC) was collected during this review.
The potential for wire replacement by plant personnel as a result of corrective maintenance or modifications was not considered a concern at BSEP because of BSEP policy to purchase and stock only environmentally qualified wire / cable for use within all Q-List safety-related electrical applications. Any modifications or corrective maintenance activities would have used an acceptable qualified wire / cable.
Following the review of the documentation, CP&L conducted a sampling of Linitorque operators to confirm that the issues raised by the IEN were not a concern at BSEP.
At the time of the receipt of the IEN, the BSEP Unit 2 was in a scheduled refueling outage and Unit I was at full-power operation. The valve operators selected for the sampling inspection were chosen on Unit 2 to prevent entering limiting conditions of operation on the operating unit.
The sampling inspection performed on Unit 2 was considered representative of conditions on both units. The Unit 1 and Unit 2 valve actuator order numbers are the same for each valve. This indicates that the valves for both units were assembled to the same requirements, thus, the internal piece parts are expected to be the same.
Additionally, the Brunswick 1
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~
Valve Actuator Specification 9527-01-248-7,Section III, D. 5, to which actuators were purchased, specifies Raychem Flamtrol or Specification 44 (Kynar) insulated wire.
At the time of the inspection, there were 114 Limitorque motor operators per unit, classified Class IE Safety Related and located in a harsh environment (10 in the Drywell, 4 in the Main Steam Tunnel and 100 in the Reactor Building).
Six of the ten valves in the Drywell were inspected.
Three of the remaining four were replaced with new Category 1 actuators and the internal wiring was identified as Raychem.
The remaining valve in the Drywell is not required to be maintained in the EQ Program.
The valve is electrically de-energized and will be removed from the plant during a future outage.
Of the four valves in the Main Steam Tunnel /MSlV Pit, three were inspected.
The remaining valve is a new Category 1 actuator which utilized Raychem wire.
Of the 100 valves in the Reactor Building, 31 valves were inspected during the outage.
The 31 valves inspected represent a sampling of 31 percent of all valves in the Reactor Building and 61 percent of the valves in critical areas with "long" operating time requirements.
This is considered acceptable as a representative sample of typical installations at BSEP. Additionally, if any case of PVC wire had been found, the sample group would have been expanded and the qualification documentation established or the wire removed.
Of the 40 valves inspected, 7 valves had wire which was identifiable as Raychem Flamtrol.
These actuators were acceptable as is and were not rewired.
Four of the drywell valves contained an unidentifiable (no manufacturer or type markings) black insulated wire.
The valves inside primary containment containing unidentifiable wire were completely rewired using environnentally qualified Rockbestos wire.
From the visual inspection of the wire, it did not appear to be PVC insulated wire.
It was concluded that the wire was provided by Limitorque and was not the result of either modifications or corrective maintenance.
Samples of the unidentified wire were sent to the CP&L Analytical Chemistry Laboratory on February 20, 1986 for analysis to determine if the wire contained PVC.
Preliminary results (per telecon February 28, 1986) of the analysis revealed that *he sample did not contain PVC and additionally the spectrophotometry indicated that the sampics of the unidentified wire insulation were essentially identical to the known control sample (Raychem Flamtrol).
Raychem Flamtrol is a cross-linked polyethylene insulating material.
Additionally, a second sample of the unidentifiable black insulated wire was sent to the CP&L Analytical Chemistry laboratory on Phrch 21, 1986.
This sample also confirmed that the insulation did not contain PVC.
I1-2 (4074PSNpgp)
An independent laboratory (Westinghouse Electric R&D Center) was contracted to perform the spectrophotometry on additional samples of the unidentified wire also using the Raychem Flantrol as the control sample.
The results of this analysis, received preliminarily on April 18, 1986 and confirmed within a final report, concluded that the Raychem control and the unknown samples were essentially identical in composition, and all specimens examined were free of PVC. Chemical differences observed between the Raychem and the unknown samples were not associated with the polyethylene " base" material; rather, differences were seen in the amount of flame-retardant additive used and in an excess amount of plasticizer material found. These may have resulted from normal manufacturing variations that could be expected from different manufacturing batches / lots, or may be attributable to what would be expected when comparing different sizes of insulation ODs (i.e., 600V versus 1000V rated insulation systems).
These separate and independent analyses, coupled with information on Limitorque's policy regarding the supply of contcol wiring, led to the conclusion that the unidentified wire is Raychem cross-linked polyethylene which was provided by Limitorque. The control wire is qualified to BSEP environmental service conditions (normal and accident) for all locations in the plant. The wire has been determined to be acceptable for use both inside and outside the primary containment for Units 1 and 2.
Valve 2-E11-F024A contained Raychem Flantrol and a wire on the torque switch which has markings which identified the wire as VULKENE type XHHW. This wire type is a cross-linked polyethylene insulated wire rated at 90*C.
No generic qualification package has been established for this specific wire manufacturer. However, since the wire insulation is a cross-linked polyethylene, it was considered to be qualifiable. This is considered to be an isolated case. No other valves inspected contained the Vulkene Wire.
The wire is not stocked at BSEP and will not be used for these applications. Technical Support concluded that the appropriate action would be to replace this wire with environmentally qualified Rockbestos and not to develop qualification package.
CP&L believes that the scope of the sample inspection was large enough and enveloped the areas of concern at BSEP.
CP&L inspected 35 percent of the total number of actuators which is a larger population size than the mininum 10 percent recommended by NRC to its inspectors. The NRC Temporary Instruction (TI) 2515/75, which is being used to aid the Regional Inspectors in determining whether the licensees have adequately addressed the concerns of IEN 86-03, recommends that the inspectors determine how many operators are installed in safety-related electric systems and harsh environments at each plant site.
After this number is established, the inspector should select a sampling of at least 10 percent of the operators or a minimum of at least four operators per unit for use in determining what wires are actually installed in the operators.
In addition, the technique utilized to identify the composition of the wire insulation (i.e., spectrophotometric analysis) provides greater confidence than the visual inspection referenced in the NRC T1.
The TI noted that, "Some wires in the operators nay not have identification on 11-3 (4074PSA/pgp)
them.
In these cases, the inspector should observe whether the wires are i
similar in appearance to other wires that are identified by markings.
If these wires do appear similar, it is reasonable to assume that the wires i
are the same."
t As indicated above, the potential for replacement by plant personnel as a t
j result of corrective maintenance or modifications is not considered a concern at BSEP.
BSEP has as a policy to purchase and stock only environmentally qualified wire for use at BSEP in all Q-List safety-related applications. Modification or corrective maintenance activities would have used an acceptable replacement wire. The inspection results confirmed that this policy has provided adequate control of the use of only qualified wire for use in modifications and corrective maintenance activities. The isolated case described above (i.e., the VULKENE wire) is not considered significant based on the number of actuators inspected.
1 i
During the next Unit I refueling outage, currently scheduled in January 1987, a similar inspection of the Limitorque actuators will be l
performed to provide added assurance that the inspection results obtained on Unit 2 are indicative of both units.
1 3)
H. B. Robinson Steam Electric Plant 1
Following receipt of IEN 86-03, HBR initiated a review to determine the applicability of the notice. The notice affected only two valves at HBR.
By February 11, 1986, the plant had determined that the existing wires could be considered satisfactory. This determination was based on 5
the fact that the original wiring had not been replaced. Therefore, the certifications from Limitorque were sufficient to support qualification.
7 This review adequately considered the concerns identified in IEN 86-03 and was consistent with the qualification requirements contained in the DOR i
Guidelines.
i l
As noted in Attachment 1, IEN 86-03 identified as a concern wires added after manufacture. For wires installed by Limitorque, the notice stated e
that Limitorque could provide or reference documentation to support qualification. However, under DOR Cuidelines, type testing of a device implicitly demonstrates qualification of all components contained in the device. Type testing does not specifically include formal traceability requirements.
Formal traceability documentation is instead generally a product of the QA requirements of 10CFR50, Appendix B.
Appendix B was
)
promulgated in 1970 and applies to equipment procured after that date.
i Therefore, for equipnent procured prior to 1970, one would not expect the i
traceability link to be a formal Appendix B paper.
Since the Linitorque 2
valve actuators at HBR were procured prior to 1970 and IEN 86-03 indicated j
that wires originally installed by Linitorque were qualified, it is reasonable to assume that the concerns in IEN 86-03 do not present a l
safety concern at HBR.
Nevertheless, as a result of the corporate activities described in Attachment I, HBR decided on April 9, 1986 to
]
replace the internal wiring during the next refueling outage to provide additional assurances.
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1 Following the August 21, 1986 telephone conversation with NRC Region 11 Staff, HBR expedited the replacement schedule.
On August 24, 1986 the wiring was removed, new Rockbestos Firewall 11I wiring installed, and the original wiring saved for testing and evaluation to determine its
)
composition.
Initial visual inspection identified the wiring as Houston Wire & Cable XLPE, for the torque switches, and as PVC TEW, for the limit switches.
The Houston Wire & Cable XLPE is a cross-linked polyethylene insulated wire.
No generic qualification package has been established for this specific wire manufacturer. However, since the wire insulation is a cross-linked polyethylene, it was considered to be qualifiable.
Qualification of PVC wire is covered by HBR qualification documentation.
Samples of the wires that were removed have been sent to the CP&L Analytical Chemistry Laboratory for analysis.
Based on the initial evaluation, CP&L believes that the original wires were qualified within the DOR Cuidelines.
II-5 (4074PSA/pgp)
.