Fiber Optic Cable Qualification Update

Transcription

1 Fiber Optic Cable Qualification Update EQTM 2018 Eric Rasmussen RSCC Wire and Cable LLC Terry Price Ontario Power Generation 1

2 Darlington Nuclear Generating Station In Service Units each generating approximately 900 Megawatt (gross electrical) Plant Refurbishment Life Extension Part of CANDU design Multi-year project Replacement of major reactor components and upgrade key plant systems 30 plus more years of clean, safe, reliable operations 2

3 As part of the Darlington Refurbishment Project the Shutdown System Display / Test Computers are replaced due to hardware obsolescence. The Shutdown System Display / Test Computers displays in the Main Control Room giving operating and Post Accident Monitoring data. Field sensors and associated instrumentation monitor various trip parameters and provide signals to the trip computers. These computers perform conditioning of trip parameters and provide real-time display signals and trip signals should a parameter exceed set point. 3

4 Fiber Optic Cable are utilized to connect the computers, while maintaining electrical isolation. Their reliable operation is important for Darlington life extension. The original design used coaxial cable that could not be qualified for the DBA Harsh Environment it was routed (end equipment is not in a harsh environment). Operations work around used Reactor Power (PAM) monitoring from the Units Secondary Control Area (Emergency Control Room) until the coax was replaced with Fiber Optic Cable. Fiber Optic Cable provides a faster response time and better quality of transmitted data. 4

5 Environmental Qualification Summary Sheets Value Documentation References Qual. Equipment Description Parameter Notes Required Demonstrated Required Demonstrated Method System: SDS1 and SDS2 Mission Time 90 Days 90 Days Ref 4, 5 and 6 3, Tab E1, Sec 3.2 Test 6 Equipment Tag: / See Note 1 and Tab 2.3 Equipment Description: See Note 2 Manufacturer: RSCC (Formerly Rockbestos) See Note 2 Model Number: FF EQ Function/Service: See Note 3 Peak Temperature ( C) , Sec , Fig T6 Peak Pressure [kpa(g)] , Sec , Figure P2 Relative Humidity (%) , Sec , Figure H1 3, Tab E1, Sec 3.1 Test 7 3, Tab E1, Sec 3.1 Test 8 3, Tab E1, Sec 3.1 Test 9 Chemical Effect(s) Yes Yes 1, Sec , Tab E1, Sec 4.2 Analysis 10 Radiation (rads T.I.D.) E6 1.17E6 1, Sec , Table NR5, Thermal Aging Life (yrs.) N/A >60@45 C N/A 3, Tab E1, Sec 7.1 and Tab MD 2.2 3, Tab E1, Sec 6.1 Test 11 Test 12 Cycle Aging (No. Cycles) No No N/A 3, Tab E1, Sec 8.2 N/A 13 Unit(s): 1234 Qualified Life (yrs.) N/A 60 Years N/A 3, Tab E1, Sec 9.1 Test 14 Location(s): See Note 4 and Tab MD1.2 Qualification Category: Category 1, 2, or 3, See Note 5 Submergence No No See Note 15 3, Tab E1, Sec 5. N/A 15 Performance Criteria See Note 16 See Note 16 See Note 16 3, Tab E1, Sec Category 1 Electrical Interface Requirements Note: None. Splices and terminations are in a mild environment. ( See Note 2) Mechanical Interface Requirements: Test 16 Note: None ( See Note 2) 5

6 Background IEEE : IEEE Standard for Qualifying Fiber Optic Cables, Connections, and Optical Fiber Splices for Use in Safety Systems in Nuclear Power Generating Stations Trial-use standard published in 2011 The standard provides requirements, directions, and methods for qualifying fiber optic cables, connections, and optical fiber splices for use in safety systems of nuclear power generating stations. Standard was affirmed in 2013 There were not any comments made during the trial-use period. Today IEEE 1682 is recognized as a Standard by IEEE. IEEE White Paper is scheduled to be published shortly The paper intends to provide background and guidance on significant topics that were discussed during the standard s creation and those topics which were deferred for subsequent revisions. Working Group is currently being formed for the 2021 revision 6

7 Fiber versus Cable Qualification The principles of qualification are identical for fiber and electrical cable, though there are significant differences in the application to fiber optic cable as compared to electrical cable EMI Fiber optic cables are largely immune to the affects of electromagnetic interference (EMI). Ohmic heating Optical fibers carry very limited power, therefore, internal heating is insignificant and can be disregarded. Radiation Induced Attenuation (RIA) Optical attenuation (i.e. power loss) may render the fiber and/or end-device inoperative. Optical fibers are especially sensitive to increased attenuation when exposed to radiation: Higher dose rates and higher total dosage results in greater RIA Higher temperatures reduce RIA Recovery of RIA may occur after the radiation source is removed 7

8 Fiber Optic Cable Design Super Rad-Hard Fiber (F doped) Hermetic Stainless Steel Tube (FIMT) Serve Wire Armor (SWA) 8

9 Fiber Optic Cable Design Core (F doped glass) Cladding (glass) Coating(s) (polymeric) 9

10 IEEE 1682 (EQ) Qualification Aging properties (section 6.4.1): IEEE section requires that where significant aging mechanisms are identified, suitable age conditioning shall be included in the type test. IEEE section requires that aging data shall be used to establish the activation energy of the critical materials. Thermal aging data was established for all polymeric layers utilized which only applies to the fiber coatings. Since the glass fiber and stainless steel tube are inert materials without significant aging mechanisms, then thermal aging data was not required for either component. 10

11 IEEE 1682 (EQ) Qualification Draft IEEE 1682 White Paper States: The optical fiber is coated with a single or composite nonconductive, thin, polymerized layer(s) that function to protect the fiber from mechanical damage and moisture ingress. The protective coating(s) acts to cushion the glass fiber from mechanical forces which could create micro bends in the fiber, thereby minimizing optical signal loss. The coating(s) also act as a moisture barrier, thereby preventing micro-crack propagation. Since the fiber coating(s) are critical to the safety function of the fiber, the Arrhenius method may be used to establish a qualified life for the coating(s). 11

12 IEEE 1682 (EQ) Qualification Thermal Aging and Activation Energies: Samples were thermally aging at 105 C for 168 hours Polymeric Layer Activation Energy Qualified Life Inner Coating ev >70 years at 45 C Outer Coating ev 70 years at 45 C 12

13 13

14 IEEE 1682 (EQ) Qualification Test samples: Sample Set #1: Unaged and Un-irradiated Sample Set #2: Unaged and 1.1 Megarads Sample Set #3: 60 years aged and 1.1 Megarads Based upon IEEE , Paragraph , since the fiber which was qualified is known to exhibit the phenomena of recovery following radiation aging, then thermal aging was performed prior to radiation aging which achieved the worst postulated state of degradation. Furthermore, simultaneous thermal and radiation aging was not performed since higher temperatures during radiation exposure would have exacerbated the recovery effect and produced a better postulated condition than what may be observed in the fiber optic cable s actual installed environment. 14

15 IEEE 1682 (EQ) Qualification Gamma radiation exposure: 1.1 Megarads total integrated dosage (TID) was based on a 2σ confidence level 15

16 16

17 IEEE 1682 (EQ) Qualification Normal service use testing: Following thermal and radiation aging: samples were straightened bent around mandrel equal to fiber s minimum bend radius visual examination optical power loss was measured on every fiber 17

18 IEEE 1682 (EQ) Qualification DBE simulation performed at RSCC test laboratory: 18

19 19

20 IEEE 1682 (EQ) Qualification Post DBE final acceptance testing: Optical power loss was measured on every fiber throughout the DBE simulation Samples functioned within the specified optical parameters throughout the DBE simulation Following DBE simulation: samples were straightened bent around mandrel equal to fiber s minimum bend radius visual examination Optical power loss was measured on every fiber 20

21 IEEE 1682 (EQ) Qualification Anomalies: 1 due to alternative optical measurement methodology employed for normal service testing 1 due to an optical switch malfunction during the irradiation exposure 1 due to DBE test chamber falling below the required profile 21

22 Thank You! Eric Rasmussen RSCC Wire and Cable LLC Terry Price Ontario Power Generation 22