ML14184A372
| ML14184A372 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 03/29/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML14184A370 | List: |
| References | |
| NUDOCS 8304060608 | |
| Download: ML14184A372 (6) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION H. B..ROBINSON STEAM ELECTRIC PLANT UNIT NO. 2 JUSTIFICATION FOR CONTINUED OPERATION UNQUALIFIED ELECTRICAL EQUIPMENT 1.0 Introduction The staff required that all licensees provide documentation which demonstrates that the safety-related electrical equipment in their plants meet the DOR guidelines; NUREG-0588 or; commit to replace, requalify or other appropriate corrective action. If a corrective action was indicated, justification for continued operation was required until the corrective action is completed. Carolina Power and Light Company (CP&L) provided detailed documentation and justi fications in their responses to IE Bulletin 79-01B in August 1981, and the staff's initial Safety Evaluation dated May 21, 1981.
The submittals were reviewed by Franklin Research Center (FRC).
As a result of their review, FRC concluded th th6 Technical.Evaluation Report (TER) dated July 8, 1982 that CP&L has stated that the equipment items are environmentally qualified; or has provided a technically sound rationale as a basis for justification for continued plant operation; or has provided a technically sound rationale or other additional information which in FRC's judgment provides a basis for justification for contfnued operation.
These conclusions were valid while the staff and FRC were continuing their review and evaluation.
However, upon completion of the effort and the issuing of the Safety Evaluation dated July 8, 1982, for H. B. Robinson Unit 2, it became necessary to reassess all electrical equipment items in TER Categories I.B, II.A, Lr.R and IV.
This Safety Evaluation addresses the six (6) items included in the TER, Table 4-1, Item II.B, Equipment Not Qualified. The licensees initial 30 day response dated February 11, 1983, indicated that the necessary justification for continued operation was provided in their previous submittal.
However, based on discussions clarifying the applicability of Appendix D of the TER, CP&L provided additional justification for item 16 and 17 in their letter dated March 4, 1983, 8304060608 830329 PDR ADOCK 05000261 P
-2 2.0 Evaluation 2.1 Criteria/Guidelines The recently enacted regulation on environmental qualification, 10 CFR 50.49, "Environmental Qualification of Electric EqUipment Important to Safety for Nuclear Power Plants," provides the appro priate guidelines for justification for contfnuedoperation.
These guidelines are included in paragraph (i) of 10 CFR 50.49. The necessary elements to be considered, where appropriate, are:
(1) Accomplishing the safety function by some designated alter native equipment if the principal equipment has not been demonstrated to be fully qualified.
(2)
The validity of partial test data in support of the original qualification.
(3) Limited use of administrative controls over equipment that has not been demonstrated to be fully qualified.
(4) Completion of the safety function prior to exposure to the accident environment resulting from a design basis event and ensuring that the subsequent failure of the equipment does not degrade any safety function or mislead the operator.
(5) No significant degradation of any safety function or misleading information to the operator as a result of failure of equipment under the accident environment resulting from a design basis event.
2.2 Evaluation The Franklin Research Center TER identified six (6) equipment items in the II.B Category as not qualified by identification numbers 12, 13, 149 15, 16 and 17.
Each of these items are discussed below.
Item 12 Pressure Transmitter -
In Containment -
Rosemount Model 1153A Pressurizer Pressure Control Signal PT-444; Pressurizer Pressure Signal for SIS Initiation PT-455. Required Operating Time:
30 min.
Transmitters located in the containment are required to perform their function within a maximum period of twenty-four (24).hours following an accident. The transmitters did not meet the IEEE 323-1974 requirement due to 0-ring failure which was attributed to the high temperature versus time necessary for the Arrehenius curve time compression to satisfy
-3 aging test requirements. This test failure would not preclude the use of the Rosemount 1153A within the H. B. Robinson Unit 2 (HBR-2) containment because it has successfully performed within the HBR-2 accident parameters of temperature, pressure and radiation levels.
0-ring failure due to high temperature should not occur during this time.period. Until full qualification is established CP&L has established a program to replace the 0-rings when yearly calibration tests are performed and a complete instrument change-out on ten year cycles, after installation dates, to maintain qualification level.
The fact that high aging temperatures vs. time used in the test will not be experienced in the containment; that the transmitters did perform satisfactorily in the accident environment; and that 0-ring change-out yearly will be accomplished provides reasonable assurance that the transmitter functions will be performed prior to a potential failure of the instrument.
This is in accordance with 10 CFR 50.49(i).
Item 13 Level Transmitter-In-Containment Rosemount Model 1153A. Monitors Steam Generators A, B and C - Wide range level,narrow range level.
LT-474, 477, 484, 487, 491, 494. Monitors Pressurizer Leveli.and Actuates SIS, LT-459.
Required Operating Time:
30 min.
The evaluation for these transmitters is the same as for item 12, therefore they are in accordance with the guidance provided in 10 CFR 50.49(1).
Item 14 Flow Transmitter-In-Containment - Rosemount Model 1153A. Monitors Main Steam Flow Loop A, B and C - FT-474, FT-484/485; FT 494/495.
Required Operating Time: 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to 1 day.
The evaluation for these transmitters is the same as for item 12, therefore they are in accordance with the guidance provided in 10 CFR 50.49(i).
Item 15 Pressure Transmitter-In-Containment - Rosemount Model 1153GA9.
Detection of Inadequate Core Cooling PT-500/501.
Required Operating Time:
Not stated.*
- Instrumentation located in the containment are required to operate within a maximum period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an accident (see item 12).
Transmitter models 1154GA3 through 9 were considered qualified because it is representative of model 1153A. Therefore, the evaluation is the same as that for item 12, This is in accordance with 10 CFR 50,49(l),
-4 Item 16 Level Transmitter-In-Containment - GEMS Model XM52495.'Containment Sump Water Level LT-801A, B, C, D. Required Operating Time:
Not Stated.*
Item 17 Level Transmitter-In-Containment -
GEMS Model XM36495.- Containment Sump Water Level LT-802A, B, C, 0. Required Operating Time:
Not Stated.*
- Transmitters in the containment are required to perform within a maximum per'iod of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an accident.
The FRC TER concluded that the,Franklin Labs Report F-C3834 was incon clusive and that FIRL Report S-C3834, supplement to F-C3834, shows that these transmitters.functioned properly for less than 90 minutes during tests in a steam exposure for the temperature/pressure profile of IEEE-.323-74. Therefore, the GEM transmitters were unqualified.
Subsequently, the licensee found the transmitters to be similar to other GPM transmitters which have recently completed a successful qualification test program to IEEE 323-1974 requirements. In addition, the licensee has left in place the. original Madison level switches LS-1925A and LS-1925B which are currently operational therefore providing a backup.
By letter dated May 4, 1982 the licensee provided the following information relative to 10 CFR 50.49(1) as justification for continued operation:
(1) Accomplishing the safety function by some designated alternative equipment if the principle equipment has not been demonstrated to be fully qualified, Justification:
The GEMs transmitters located in the containment sump provide sensor input to detect water level changes within the sump from the bottom of the sump to +35 feet. This sensor signal is transmitted to the control room for display purposes. This is an independent, self-contained system which does not initiate any safety related action or become an integral to any safety action sequence during or after accident situations. As installed this system replaced the function of the originally installed water level measurement system consisting of Madison level swtiches model number 5602 and designated; LS-1925A and LS-1925B. The Madison system was superceded by the GEMs system In order to provide a more dynamic water depth indication and to provide a better qualification documentation package. Currently both systems are operational.
(2)
The validity of partial test data in support of the original qualification.
-5 Justification:
To augment the initial qualification package as provided by the manu facturer (Franklin Labs Report F-C3834, Supplementary Test of a Liquid Level Sensor Under Conditions Simulating a.Loss-of-Coolant Accident Within Containment of a Muclear Power Generating System, dated March 1974) and declared inadequate by Franklin Research Center Technical Evaluation Report, CP&L H. B. Robinson Unit 2, dated July 8, 1982, (items 16 and 17) the following additional analysis is provided:
Component materials of the GFMs level transmitters have been identified.
These materials have 'been evaluated per NUREG-0588 guidelines and by applying Arrhenius techniques. Results of this analysis indicate that the materials in these transmitters, metals, neoprene, mineral-filled phenolic, glass-epoxy laminate, wire-wound resistors, silicone rubber and silicone fluid would not be significantly affected by the postulated environment, The mineral-filled phenolic has an expected life of 120 years (lowest of the component materials)-at the plant postulated normal environment (120*F) and an expected life of 300 days at the peak accident temperature (2860F). Therefore, it is reasonable to expect these items will continue to perform their safety related function, These transmitters are generically similar to other transmitters produced by GEMs which have recently completed a successful qualification program to IEEE 323-1974 requirements, including thermal aging.. Once the qualification documentationis made available., an analysis will be performed to assess qualification to H. R. Robinson plant specific conditions and equipment similarity. This report will be available prior to the May 20, 1983 requirment-for submittal of our complete equipment qualification compliance plan, (3) Limited use of administrative controls over equipment that has not been demonstrated to be fully qualified.
Justification:
This water measurement system is a passive system requiring no operator initiation or manipulation; therefore, no administrative control is applicable.
(4) Completion of the safety function prior to exposure to the accident environment resulting from a design basis event and insuring that the subsequent failure of the equipment does not degrade any safety function or mislead the operator.
As stated in (i)(l)'andd(i)(3) the containment sump water level system is an independent system providing a singular function which does not initiate or become a serial contributor for any safety function. Its ability to operate before and after a design basis event has been analyzed within
g 0
-6 (i)(2) above and determined to be satisfactory. At present there is no' planned action to remove or disconnect the initial Madison water level swttches; therefore, comparative readings are available to the operator, or if failure should occur tn-one.system, the other provides sumprwater level information to the operator, (5) Mo significant degradation of any safety function or misleading information to the operator as a result of failure of equipment under the accident environment resulting from a design basis event.
Justification:
As analyzed in (i)(2), the GEMs system should perform its function under the accident environment resulting from a design basis event.
Failure mode of the water level systems would be direct failure, either data is present ov absent, therefore, information presented should not be misleading to the operator. As two redundant GEMs systems are provided: as well as, a backup Madison system, water level information should be available in unambiguous display in case of single failure.
Based on our review, we have conduded that:
A. The justification for continued operation provided by CP&L for H. B. Robinson Steam Electric Plant Unit No. 2 is in accordance with the guidance provided in 10 CFR 50.49(i) for items 12, 13, 14 and 15.
B. The additional justification for continued operation provided for items 16 and 17 by the licensee's letter of March 4, 1983, is in accordance with the guidance provided in 10 CFR 50.49(i) and, C. Reasonable assurance exists that the plant can be operated in a safe manner pending completion of qualification data and corrective actions which are acceptable to the staff. This equipment must be fully qualified in accordance with the schedule provided in 10 CFR 50.49.
Date:
March 29, 1983 Principal Contributor:
G. Requa