IA-85-160, Trip Rept of Site Visit During Wk of 831031 Re Physical Arrangement & Installation of Electrical,Instrumentation & Control Equipment.Compliance W/Nrc Design Criteria Confirmed
| ML20127B510 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek, Callaway, 05000000 |
| Issue date: | 04/13/1984 |
| From: | Rosa F Office of Nuclear Reactor Regulation |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20126H338 | List: |
| References | |
| FOIA-85-160 NUDOCS 8404260420 | |
| Download: ML20127B510 (32) | |
Text
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(PG ApR 13 BN MEMORANDUM FOR: B. J. Youngblood, Cnief, Licensing branch #1 Division of Licensing FROM: F. Rosa, Chief, Instrumentation & Control Systems Branch Division of Systems Integration
SUBJECT:
SifdPPS SITE VISIT - ICSB Plant Name: SNUPPS - Callaway Plant. Unit 1; Wolf Creek Generating Station Docket Nos.: 50-483/482 Licensing Status: OL Responsible Branch: LB #1 Project Manager: J. holonich Review Branch: ICSB Review Status: Incomplete for Site Visit (Additional Information Required From Applicants)
Enclosed is the Instrumentation and Control Systems Branch (ICSB) trip re-port for the SNUPPS (Callaway and Wolf Creek) site visit performed the week of October 31, 1983. The purpose of the site visit is to confim that the physical arrangement and installation of electrical, instrumenta-tion and control equipment are in accordance with design criteria and de-scriptive information reviewed by the staff. A site visit is part of the nomal review process and is conducted in accordance with the Standard Re-view Plan, NUREG-0800, Appendix 7-B, General Agenda, Station Site Visit.
In general, the instrumentation and control systems inspected appeared to be installed in accordance with the applicable design criteria. A few minor deviations and areas of concern were noted during the site visit.
These were brought to the attention of the applicants and are discussed in the enclosed ICSB trip report (Section B: Items I.c II.f II.h, IV.d, VI.a.VI.c,VI.1,VI.k.(1),VI.k.(2),andIX.e). Some issues were re-solved during the site visit based on cowitments made by or further discussion with the applicants. For other issues, the applicants submitted additional infomation to either e.tsolve or further con-fim the items of concern. One issue (Secti.19 of. the enclosed trip report: Item XII.b) requires that the applich ; submit infomation to further confirm the design.
The enclosed trip report should be made available to the Region III and Region IV offices. The regional offices should pay particular attention to the iteas in Section B that are marken witn an asterisr. which signify specific concerns that resulted fron ICSB's site visit. Eacn regional
Contact:
i:. Stevens, ICSB A29%5
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office may want to include these particular areas in its audit progran to verify tnat comnitments are followed and tnat various equips.ent installa-tions are satisfactorily completea prior to core load. It should be noted that the issue (Section B: Iten I.c) related to the PAST valve house ficoding concern requires that the respective regions verify (ts part of pre-fuel load inspection) that appropriate precautions have been taken to correct the situation. Refer to Section B (Iten I.c) of the enclosed trip report for details on this issue.
Section C of the enclosed trip report identifies those SER confiraatory items which have been resolved based on the ICSD site visit. It should be noted that the ICSB determined that further consiceration should be s,1ven to the control room layout as it relates to auxiliary feeawater control . For details see Item VI.a. in Section b of the enclosea trip rel.o rt . This issue should be included as part of the Human Factors Engineering Branch (HFE8) detailea control roori design review.
The site visit, which was performed in accordance with Section 7.1.3.4 of the ShuPPS SER, confirmed that the design, in general, has been prop-erly implemented to meet the applicable criteria. For tne confirmatory issue listed above, the applicants have been requestea to provide the additional information required in Section B. based on the enclosed trie report and pending receipt of the additional confirmatory information, the staff considers that the purpose of the site visit has been satis-factorily accomplished.
" Original si Ened By:
Paust Rosa =
Faust Rosa, Chief Instrumentation & Control Syster.s brancn Division of Systems Integration DISTRIBUTION:
Enclosure:
Docket File As stated ICSB R/F cc: K. hattson R. Stevens (PF)(2)
J. Calvo n.W. Houston F. Raa J. Holonich SNUPPS S/F H. Capra Callaway S/F J. Weisler. Reg.111 Wolf Creek S/F S. Senua, Reg. IV M. Virgilio R. Eckenrode R. Kendall V. tioore J. Mauck f- g a f
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' f Enclosure ICSB TRIP REPORT SITE VISIT - SNUPPS PLANTS (CALLAWAY/ WOLF CREEK)
(OCTOBER 31 - NOVEMBER 4, 1983)
Section A An of ficial site visit by the Instrumentation and Control Systems Branch (ICSB) was conducted at the Callaway Plant, Unit 1 and Wolf Creek Gene /I$ing Station during the week of October 31, 1983.
In general, the installation of the various I&C systems appeared to follow the guidelines of applicable design criteria. Only a few mino deviations and areas of concern were noted during the site visit and are described in Section B of this report. Some issues were resolved during the site visit, others required additional information to be submitted from the applicants beyond that supplied to the staff during the site visit.
The inspection of selected 1&C equipment and systems followed the outline of an agenda which was submitted to the SNUPPS applicants several weeks prior to the NRC audit. The site visit agenda is described below:
O e
(Asterisked items were performed at Wolf Creek on Thursday 11/3/83)
I. Preliminary Discussion
- a. Plan for audit including a general discussion of the plant layout and plant evolutions in progress.
- b. Isolation devices for B0P ESFAS actuation signals. Should include discussion (using drawings) of the interconnection between separation groups.
- c. Environmental control systems (HVAC/ Heat Tracing) required for safety related systems. Should include discussion on freeze protection for instrumentation sensing lines and on control room annunciation to alert the operator to take cor-rective actions in case of failure of required environmental control systems.
d .' Preoperational testing to verify that safety related systems will not change state upon reset (i.e., remains in emergency mode after reset).
II. Shutdown from Outside the Control Room
- a. 1.ocation of remote shutdown panel
- b. General layout of panel
- c. Identification of controls
- d. Habitability of remote shutdown panel location
- e. Potential for damage from missiles, flooding, pipe whip, etc.
- f. Verify that physical separation and electrical isolation requirements for redundant instrumentation and controls are r.et .
- g. Examine the manual transfer switches
- h. Verify hot and cold leg temperature indications on the remote shutdown panel e
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III. Reactor Building, Auxiliary and Turbine Building
- a. Arrangement of instrument panels / racks associated with plant protection systems (separation and layout)
- b. Potential for instrument damage due to missiles, flooding, pipe whip, etc.
- c. Component separation and isolation
- d. Panel wiring separation and isolation
- e. Separation and independence of piping and wiring to redundant or diverse instruments
- f. Provisions for testing protection instruments IV. Cable Runs and Cable Spreading Area
- a. General layout
- b. Implementation of separation criteria (Verify-identification of Class 1E raceways and check cableidentification)
- c. Check routing of power cables (embedded conduit, separate safety-class structure)
- d. Verify that cable penetrations meet physical separation and electrical isolation requirements V. Vital Instrumen'taEion and Control Power Supply Installation
- a. General layout
- b. Physical and electrical separation
- c. Potential for damage from missiles, high energy line break, etc.
- d. Batteries, inverters, etc.
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4-VI. Control Room
- a. Review general layout of the control room
- b. Examine manual reactor trip controls to verify tnat
- separation and isolation requirements are met
- c. Examine overall display instrumentation importan to
. safety
- Concentration will be on the bypassed and inoperable status indication for ESFAS and RPS as it relates to R.G. 1.47. Particular attention will be paid to the automatic indication of the block of the signals which initiate auxiliary feedwater on loss of both main feed-
, water pumps.
- d. Inspect instrument cabinets, engineered safeguard cabinets, RPS cabinets, isolation cabinets (arrangements, layout, separation,etc.). (SA036,SB038,SB029A)
- e. Review Rod position indication
- f. Review Protection system initiation and status panels
- g. Review Engineered safety feature initiation and status panels
- h. Inspect operation of the safety injection accumulator isolation valves
- Review procedure for removing power from these valves when they are locked in the open position
- Check visual indication of the open or close status of the valves per requirements of ICSB BTP 18
- Check for the independent audible and visual alarm provided when the valves are not fully open ,
- i. Examine the readouts provided to detennine the position of the pressuri2er safety valves and the PORV's
- j. Check for temperature, pressure and level indication for pressurizer relief tank
- k. Review Panel Cabling / Wiring
- Inspect redundant components and wiring on control panels
- Verify that physical separation and electrical isolation requirements are met
- Verify that protection system wiring and control wiring are properly separated
- 1. Examine the routing of non-safety related and safety related cables within the NSSS - supplied cabinets
- m. Verify the position indication for isolation valves associated with the essential water to the air compressors
- n. Examine control switches for hydrogen recombiners
- o. Verify control room annunciation for operation of transfer switches VI I I. Remote Shutdown Procedure Walkthrough
- a. Physical walkthrough using emergency procedure required in case of control room evacuation (should include discussion on the number of people that would be required to achieve shutdown from outside the control room, the accessibility /
security of the remote shutdown station (s), etc.)
IX. Reactor Trip System
- a. Motor Generator Sets
- b. Switchgear O
- c. Physical and electrical independence i
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- d. Provisions for testing (should include walkthrough of typical actuation channel test per technical specifications from sensor to and including actuation of reactor trip breakers)
- e. Examine test jacks required to facilitate testing of P-4 interlocks X. ESF Systems and Pump Rooms
- a. General arrangements
- b. Switchgear rooms c ." Physical and electrical independence d., Potential for damage due to flooding, missiles, etc.
- e. Cabling and equipment identification l
XI. Instrument Piping
- a. Physical examination
- b. Potential for damage from missiles, flooding, pipe whip, etc.
XII. Circuit Traces from Sensors to Final Actuation Devices
- a. Check the wiring and circuitry associated with'the turbine trip input to the reactor protection system. Trace wiring for redundant channels of the trip system from.the trip devices (sensors) through to the RPS cabinets. Check isolation devices .
- b. Trace the instrument piping and circuits for redundant channels of the pressurizer inputs to the protection
! system (from instrument piping to transmitter to RPS l
and ESFAS cabinets to final actuated devices) l w
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- c. Trace selective non-safety related cables associated with the NSSS supplied cabinets
- d. Trace the instrument piping and circuits for the re-dundant channels of the steam generator low level inputs to the protection system (from instrument piping to transmitter to RPS and ESFAS cabinets to final actuated devices). Concentration will be on the ESFAS portion related to the isolation devices associated with the inte. connection between separation groups used for initiation of auxiliary feedwater
- e. Trace the turbine trip upon reactor trip circuitry.
Verify that the maximum credible faults were con-sidered in routing of these circuits within the turbine building. Check isolation devices used to prevent degradation of RPS due to credible faults within the turbine building l
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Section 8 (Detailed Discussion)
Following is a detailed summary and discussion on the instrumentation and control systems and equipment observed. The summary below follows the agenda outli; a given in Section A above. The items preceded by an asterisk de6ote specific areas of conccrn that resulted from'ICSB's site visit.
I. Preliminary Discussion
- a. The site visit began with a brief discussion of the plan for
, the plant audit including the general plant layout and evolu-tions in progress. The staff confinned that the design bases for Callaway are identical to that for-Wolf Creek in the I&C area.
l l b. The applicants provided a discussion (using drawings) describ-1 ing the use of isolation devices for the B0P ESFAS actuation l channels where interconnections exist between various separa-tion groups. The staff also verified the separation by actu-ally viewing the B0P ESFAS cabinets. Separation appeared ade-quate.(SeeSERSection7.3.2.6)
There was some discussion on the Automatic Test and Indication (ATI) System. The overall test concept appeared to be acceptable to the staff. To further support the BOP ESFAS design, the staff k
. . 1 audited design documentation on the ATI system. No problems were identified.
- c. The environmental control systems (HVAC/ heat tracing) required for safety-related systems were discussed. The staff verified that am-bient temperature alarms exist in the main control room to alert the operator should the ventilation systems malfunction. There was one exception related to freeze protection within the auxiliary building. Unit heaters are placed in various areas throughout the auxiliary building to protect against freezing. However, there are no low temperature alarms used to alert the operator that the heat-ers have failed. Sensors are used throughout the auxiliary building to alarm in the control room high temperature conditions. The ap-plicants stated that these high temperature alarms are electrically independent of ventilation systems such that a failure of the en-vironmental control system (s) will not disable the operability of i the alarming system.
The applicants provided additional information to justify the design as it relates to the auxiliary buildi.ng freeze protec-tion concern discussed above. Following the issuance of NRC IE Bulletin 79-24, the applicants reviewed the SNUPPS design
l to determine if any safety-related instrument lines could be subject +o freezing during periods of extremely cold weather.
The applicants determined that all safety-related sample and in-strument lines are to be located sufficiently remote from cold walls and exterior openings to preclude local freezing problems.
Only the roof, the south wall, and a portion of the west wall are-exposed to the outside ambient conditions so that the effects of the ambient temperature on the auxiliary building, as a whole, are minimal. Even with a complete loss of the auxiliary heat system, there should be no sudden changes in the interior temperatu res. Also, at least every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, plant operators will patrol general areas of the auxiliary building. Based.on the above discussion, the staff concludes that the SNUPPS design and operations will provide adequate freeze protection for safe-ty-related instrument lines routed within the auxiliary building.
The refueling water storage tank (RWST) has' safety-related I&C which is located within the RWST valve house structure. The RWST is heated with auxiliary steam and has associated with it two re-dundant, Class 1E tenperature sensors which providd~ indication and alarms in the control room. A heated valve house is provided which
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houses safety-related instrumentation. A temperature sensor is provided to alert the operator of a low temperature in the RWST valve house. The alarm is electrically independent of the unit heater power supply.
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It should be noted that while observing the RWST valve house structure at Wolf Creek, the staff noticed a considerable amount (4 f eet) of water standing in the bottom (underneath ground level flooring). The staff expressed a concern because the four divisional, Class 1E termination cabinets associated with the RWST were half submerged. The applicants were alerted to the fact that they should provide information to describe what pre-cautions will be taken to ensure that such apparent flooding will not detrimentally affect safety-related I&C associated with the RWST. The applicants responded by letter (N. Petrick of SNUPPS to H. Denton of NRC) dated February 23, 1984. The applicants stated that, due to the intermediate stage of con-struction of the roof, water was apparently allowed to enter the RWST valve house. Upon observation by the staff, the applicants had the water pumped out immediately. The applicants have stated that water will te prevented from entering the subject structure because of site. grading and elevations in combination with water-proof seals for roof piping penetrations. It should be noted that the Class 1E junction boxes are about 10 feet below grade level.
.The ICSB was informed by the Wolf Creek NRC Resident Inspector on Ma rch 28, 1984 that there was approximately 2 feet of water
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still standing in the bottom of the RWST valve house and tnat the roof appeared to be adequately covered. Also, the ICSB was notified that the Class 1E termination cabinets had not been open-ed for inspection and cleaning since being submerged. Based on these recent findings, the Resident Inspector felt it necessary and, therefore, planned to notify responsible plant management personnel of this situation so that corrective actions could be taken (i.e., ensure that the Class IE cabinets will be inspected and cleaned, installation of a sump pump and/or level nonitoring instrumentation, relocate the Class 1E termination cabinets, etc.).
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Therefore, this issue should be included in the list of items to be verified (as being adequately resolved by the applicants) by respective regional personnel as part of pre-fuel load inspec-tion. The staff considers this issue to be resolved pending final verification by regional personnel that appropriate pre-cautions have been taken by the applicants to ensure that flood-ing will not detrimentally affect safety-related I&C associated with the RWST. No further evaluation is necessary unless unan-ticipated problems are found as a result of the Region pre-fuel load inspections.
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- d. The preoperational testing required by IE Bulletin 80-06 was dis-cussed to verify that safety related systems will not change state upon reset (i.e., remains in emergency mode after reset). The applicants stated that this testing has not been performed but will be completed in two phases just prior to fuel load. The staff finds this acceptable. (See SER Section 7.3.2.1)
II. Shutdown from Outside the Control Room The staff's final conclusions on remote shutdown have been reported in a supplemental safety evaluation report (memorandum f rom R.W.
Houston to T. Novak dated March 1,1984). The site visit showed that the overall remote shutdown scheme for SNUPPS appears to be adequate.
- a. The auxiliary shutdown panel room is located in the northeast corner of the auxiliary buildirg one level below the control Poom.
- b. There are two distinct auxiliary shutdown panels at this io-cation; one panel (118A) is associated with instrumentation O
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,, 0 and control circuits used for controlling safe shutdown equip-ment in train A; the other panel (118B) is associated with instru-mentation and control circuits used for controlling safe shut-down equipment in train B. The panels are separated by a cinder-block wall (approximately 8 inches thick).
- c. Controls and indicators appeared to be adequately identified.
- d. The room containing the auxiliary shutdown panels appeared to have adequate ventilation and is of sufficient size to accommo-
. date several people. The room is provided with a temperature sensor which provides a high alarm in the control room.
- e. The potential for damage from missiles, flooding, pipe whip, etc. is minimized by a concrete block enclosure around the panel .
- f. The guidelines for physical separation and electrical isolation of redundant safety and nonsafety-related controls, indicators, and associated wiring have been adhered to for the auxiliary l
l shutdown panels with two exceptions. Each panel contains re-dundant divisions of safety-related wiring in combination with i
l non-safety circuits. Panel 118A at Callaway showed a lack of i adequate separation between wiring for Division 1 and Division 3 instruments (Tag numbers AL-HK-9B and AB-PIC-3B respectively).
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Also, the staff noticed the lack of adequate separation at Wolf Creek (panel 118B) between wiring for Division 2 and Division 4 instruments (Tag number FC-H1K-313B for Division 2 instrument).
The applicants stated that work plans are still underway for these panels and will require that tarriers be installed to ade-quately separate these channels. It should be noted that the Wolf Creek situation was more of a concern since it appeared that the installation of a barrier would La very difficult and did not show indications that a barrier was to be installed,
- g. During the site visit the NRC staff walked through the procedural steps required in the event of control room evacuation. This pro-vided the NRC staff with a clear understanding of the functions involved such as transfer capability, security systems, control locations, etc.
Transfer switches are located on auxiliary shutdown panel 118B which isolate and remove control from the control room for train B safe shutdown equipment necessary to take the plant to (and j maintain the plant in) a hot standby condition independent of the control room. The staff verified that process cabinets are lo-cated outside the control room for train B component isolation.
l Drawings were looked at for the required analog (indication) i solati on. The staff also reviewed various electrical schematics I
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to confirm the isolation for the control functions,
- h. The staff verified the redundant hot and cold leg temperature in-dications on the auxiliary shutdown panels. It should be noted that the ICSB site visit confirmed that only Train B indication for the subject parameter is seismically qualified. The staff's position is that the remote shutdown equipment, including the in-dicators, required for hot standby should be redundant and seismic-a.lly qualified. This issue was resolved as part of the overall staff remote shutdown review on SNUPPS and was reported in a supplement to the SER by memorandum (R. Houston to T. Novak) dated March 1,1984.
III. Reactor Building, Auxiliary Building and Turbine Building
- a. Redundant protection system instruments located throughout the reactor, auxiliary, and turbine buildings were found to be ade-quately separated. Separate mounts are used for each instrument instead of multiple instrument racks. This approach appeared to allow for more efficient routing of instrument piping to ensure compliance (to the maximum extent possible) to regulatory separ-ation and independence criteria. It should, be noted that although all instruments were tajged with labels, channel identification was not obvious. The c61or coding on associated wiring and con-duit had to be ascertaiped to identify the channel. }
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- b. Tne instruments observed appeared to be located so as to pre-vent damage due to missiles, flooding, pipe whip, et . Tne ap-plicants stated that hazards analyses are performed, taking into account potential events, to ensure proper routing of in-strument piping and placement of its associated instrument.
- c. See item a. and b. above.
- d. Various auxiliary relay rack cabinets were inspected. These cab-inets are typically used for solenoid valve control circuits and for multiplying functions for starters. The staff concentrated on the routing of nonsafety cables within the cabinets. Isolation devices (coil-to-contact) were observed whereby safety circuits send signals to the control room for alarms. It appeared that the separation between safety and nonsafety wiring was adequate.
Each cabinet is an enclosed metal structure and is associated with only one division of safety-related power.
- e. Separation and independence of piping and wiring to redundant and diverse instruments appeared to be naintained throughout the plants. (See item XII. below)
- f. Plant personnel discussed procedures for testing the instru-
, mentation. Adequate provisions appeared to be proviced for testing the protection instrumentation.
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IV. Cable Runs and Cable Spreading Area
- a. The Callaway and Wolf Creek plants both utilize two separate cable spreading rooms (one directly below the control room and the other directly above). The cable spreading rooms essent-ially consist of several stacks of cable trays.
- b. The installation of the cables and cable trays appeared to follow the physical separation and electrical isolation
. guidelines recommended by R.G.1.75.
Trays and cables were color coded for identification.
- c. Both upper and lower cable spreading rooms have power cables (480 Vac) routed through them. These power cables are associ-ated with control room HVAC equipment and are routed in conduit within the cable spreading rooms. Separation appears to be ade-quate between the I&C circuits and the power circuits.
- d. During overall inspection of the penetrat. assembly separation at Callaway, the staff noticed that redundant divisional (Divisions 1 and 3) conduits fed penetration Box ZNI-288. This was in con-flict with the SNUPPS proposed containment penetration assembly design whereby each penetration is to be as'sociated with only one division. The applicants looked into this potential concern and verified (thru drawings) that the Division 3 (blue) conduit
should have gone to Box ZNI-295 (a Division 3 penetration).
The drawings showed that this mistake had already (prior to site visit oy ICSB) been identified and corrected. The staff inspected the interior of Box ZNI-288 and noted that it contained only Division 1 (red) cables pulled through the appropriate con-duit. No cables were pulled through the Division 3 (blue) con-duit. This issue is considered resolved.
V. Vital Instrumentation and Control Power Supply Installation
- a. The SNUPPS plants vital instrumentation and control power supply (chargers, inverters, AC/DC distribution panels) are located in four separate distribution rooms.
- b. Adequate physical and electrical separation appeared to be pro-vided between redundant power supply groups.
- c. Adequate isolation of batteries, inverters, battery chargers, etc. appeared to be provided to protect for'~ damage f rom missiles, high energy line breaks, floods, etc.
- d. The four divisional (safety-related) battery systems are each located in its own separate enclosed room. 'The staff verified that the battery rooms are fed from safety-related ventilation sy stems. Drawings were reviewed as pa rt of verification.
VI. Control Room
- a. The general layout of the control room was reviewed. All con-trols and indicators inspected were found to be quickly and easily accessible.
The ICSB staff did notice that the auxiliary feedwater (AFW) control scheme layout may require further consideration. The system level initiation switches are located on the engineered
, safety features (ESF) panel; The component level AFW controls are to be operated from the operator's console which is about 15 feet away from the ESF panel. It was not made clear as to why these controls and indications were split up this way. This issue should be included as part of the control room design re-view which' is performed by the Human Factors Engineering Branch (HFEB).
- b. The manual reactor trip: controls were inspected and found to be acceptable. (See Section 7.2.2.5 of the SER)
- c. The staff examined the overall display instrumentation important to safety and found it to be sufficient with one exception re-lated to bypassed and inoperable status indication (R.G.1.47).
Overall, the bypassed and inoperable status indication system appeared to provide adequate annunciation for the ESF systems on
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the main control board. Particular attention was paid .to the interaction between the diesel generators (DG) and the . bypassed and inoperable status system. Wnen the DG is rendered inoperable, indication of this is provided automatically on the bypassed and inoperable status panel. However, this will not indicate that all train associated ESF systems are also in effect rendered in-operable. The staff was concerned that this could lead to a situ-ation whereby redundant ESF trains may be rendered inoperable simultaneously without operator awareness (i.e., DG is inoperable and ESF system in redundant train is removed from service for maintenance or repair). Through subsequent discussions with the l
applicants, it was revealed that the loss of offsite power coin-cident with an inoperable DG will result in automatic indication (on the bypassed and inoperable panel) of all train associated ESF systems affected. Based on this design feature, the staff considers the DG inoperable issue resolved.
The staff verified implementation of the automatic indication of the block of the signals which initiate auxiliary feedwater on loss of both main feedwater pumps. This resolves SER con-firmatory items (33) and B (30) for Callaway and Wolf Creek
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respectively. (See SER Sections 7.2.3,7.3.2.7,and7.5.1)
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. d. The layout of the instrumentation cabinets (NSSS engineered safeguard cabinets, RPS cabinets, and BOP ESFAS cabinets) in the control room provide easy accessibility, both front and rear. Separation between safety divisions / channels appeared to be maintained ir, accordance with R.G.1.75 with one exception associated with the NSSS 7300 process cabinets (See item 1. below).
The B0P ESFAS cabinets were inspected to verify separation and
, isolation between redundant ~ divisions. The routing of the circuits were found acceptable.
- e. The rod position indication methods were inspected. The SNUPPS plants have two methods for obtaining rod position which are 1) the digital rod position indication system and 2) rthe demand posi-tion system. Also, rod bottom alarms are provided in the control room through the digital rod position indication system.
- f. & g. Upon examination, it was concluded that sufficient instrumentation and controls exist in the main control room to provide initiation and status of both the engineered safety features system and reac-tor trip system.
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- h. The controls for operating the safety injection tank accumu-lator isolation valves were examined. Redundant, visual indi-cation of the open or closed status of the valves is provided in the control room as well as independent audible and visual alarms if the valves are not fully open. Also, power is removed after the valves are opened.
- i. The staff verified that readouts will be provided in the control room to determine the position of the pressurizer safety valves and the power operated relief valves (PORVs). Redundant, Class 1E position indication is provided through the use of limit switches. The control board labeling was not complete for the PORV's at Callaway. Also, the installation of the block valve and PORY controls was not complete at Wolf Creek. The location for the controls (RL-21) was verified. The PORV anc Dlock valve I&C should be implemented prior to core load.
J. Temperature, pressure, and level indications are provided on the main control board for the pressurizer relief tank. These indications serve as a backup to the limit switch indication described in item 1. above.
- k. ,Redundant control and indicator components mounted on the con-
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trol boards and cabinets were examined to ensure that adequate
physical and electrical separation was maintained. Overall, inspection of the cabling entering the control boards and cabinets verified that the guidelines for separation between redundant protection wiring and Tar separation between protec-tion wiring and control wiring appeared to be followed. A few minor problem areas were noted as follows:
- (1) While inspecting the rear section of the Callaway main control boards (Panels RL 17 & 18), a situation was found where separation was not adequate between safety and non-safety-related cables. Nonsafety-related cables associ-ated with the 7300 process cabinets were routed within 6 inches of two redundant safety divisions (red and yellow) without any barrier. The applicants stated -that installa-tion of the safety-related cables was incomplete and that a portion of the safety cables will -be mounted on a verti-cal steel bar to obtain adequate separation (greater than 6 inch air space). The staff inspected the referenced mount and verified that this should ' correct-the situation.
Further, the applicants stated that final Quality Control (QC) inspections had not been performed yet and that such specific instances as described above should be found dur-ing the QC inspection phase.
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- (2) While inspecting the rear section of the Callaway and Wolf Creek main control board panels RL 23 & 24, the staff noticed the lack of sufficient separation between nonsafe-ty-related circuits (Tag Nos. FAP 1-13, FAL 1-7A, and KAP-1-10) and Division 4 cables. To correct this problem, the : applicants issued field reports (SFR-RL35A and SFR-RL 64I respectively) which will require that the cables be relocated and secured to obtain at least a 6 inch air space. The staff finds this acceptable.
- 1. The staff examined the routing of the nonsafety-related and safety-related cables within the NSSS supplied cabinets. The nonsafety-related cables are not separated from the safety-re-lated cables within the cabinets. The applicants reconfirmed the staff that analyses and tests have been performed to ensure that credible faults in the nonsafety-related cables will not degrade the safety-related circuits below an acceptable level.
The applicant referenced WCAP-8892-A which has been reviewed and accepted by the staff. The staff traced selective nonsafe-ty-related cables cto verify that these circuits were indeed low voltage and were routed so as not to al' low faults greater than those analyzed for by the WCAP (500 Vac, 250 Vdc). The majority of the nonsafety cables are routed directly from the
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7300 process rack to the main control boards. Several are routed from the 7300 cabinet to the auxiliary shutdown panels (ASPS).
The applicants verified that the circuits associated with the ASPS are routed in low level cable trays - typically 48 to 24 volts d.c.
or 120 volts a.c., No problems were found by the staff. (See SER Section 7.2.2.7)
- m. The staff verified that position indication exists for-isolation ~
valves associated with the essential service water to the air
, compressors. (See SER Section 7.6.5)
- n. Control switches for the hydrogen recombiners were examined.
(See SER Section.7.3.1.6)
- o. Annunciation is provided in the control room to indie. ate those components whose control functions have been transferred to the remote shutdown location.
VIII. Remote Shutdown Procedure Walkthrough (See item II.g.).
IX. Reactor Trip System -
- a. Two independent motor-generator sets are provided for control rod power. Separation was found acceptable.
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- 27 b.& c. Adequate physical and electrical separation of the motor-generator sets, associated cabling, and associated switch-gear are provided. The staff concluded upon inspection of the reactor trip breaker: cabinets that there appeared to be adequate space for mounting the automatic shunt trip equip-ment.
- d. The staff walked through typical test procedures for RTS initiating trip circuitry. It appeared that adequate provi-sions exist for testing the RTS initiating trip circuitry inclu-ding the reactor trip breakers while the plant is at full power.
- e. Examined the location for the. equipment (to be installed) to allow periodic verification of the P 4 interlocks. Installa-tion to be complete prior to fuel load. (See SER Section 7.3.2.2)
X. ESF Systems and Pump Roons a.& c. Overall, the SNUPPS plants appeared to have adequata physical sep-aration between the redundant ESF equipment trains. For example, the ESF pumps are located in separate rooms or bays.
- b. The staff examined the ESF switchgear rooms. There are two rooms (One Division 4 and the other Division 1). No problems were
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- d. Instruments / equipment are located behind walls or other barriers to provide protection against damage from missiles, pipe whip, etc.
- e. Cabling and conduit are color-coded to indicate channel identi-fication. However, instrument identification labels, in general
- do not provide channel identification. (See item III.a) -
XI. Instrument Piping
- a. ' Several spot checks were made of the instrument piping from the
, reactor vessel or process pipe to the sensor. In all cases, ade-quate separation was noted between redundant channels and between safety and nonsafety-related channels.
- b. Fcn the process . lines observed, stainless steel tubing is util-ized. Adequate protection appeared to be provided to protect against damage from missiles, flooding, pipe whip, etc.
XII. Circuit Traces from Sensors to Final Actuation Devices
- a. The staff examined the wiring and circuit routing associated with the turbine trip input to the reactor protection system.
The staff confirmed that the circuitry used for input of tur-
. bine trip signals is Class 1E and is routed in such a manner that it wouldn't degrade the functional performance required of the reactor trip system. (See SER Section 7.2.1)
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- b. The instrument piping to the four pressurizer pressure .trans-mitters and the wiring from the transmitters to the RTS and ESFAS cabinets were traced. Adequate identification and phy-sical separation appeared to be provided. The staff requested the applicants to submit a complete set of " inter-connecting wi ring diagrams" and " process control block diagrams" associated with the pressurizer pressure input: channels as further verification of the installed design. The applicants agreed to do this upon formal request from the. staff. This trip report will be used to state such a request.
- c. (See item VI.1 ).
c d. The staff traced the instrument piping and circuits for a re-dundant channel of the steam generator low level inputs to the protection system. The installation was found acceptable.
(See SER Section 7.3.2.6)
- e. The staff traced the turbine trip caused by reactor trip circuitry to verify that maximum credible faults were considered during routing of these circuits. The staff verified:that tre circuits are routed in conduit from the turbine building to the cable spreading room. The staff reviewed GE drawings M-865-D268-02 and M-865-0265 to further confirm the installed design.
(See Section 7.2.2.3) i
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Section C (SNUPPS SER Confirmatory Items)
The following confirmatory items for Callaway and Wolf Creek, respectively, are considered resolved based on the ICSB site audit.
(7), B (8) Steam generator level control and protection - The staf f veri-fied that the design is implemented such that a two-out-of-four high steam generator level signal will isolate main feedwater fl ow. (SER Section 7.3.2.8)
(33),-B (30) Automatic indication of block of signals initiating auxiliary feedwater following trip of the main feedwater pumps - See item VI.c. of Enclosure 1. (SER Section 7.3.2.7)
(34),B.(33) Indicator, alarm, and test features provided for instrumenta-tion used for safety functions - The staff verified that the applicant has implemented, on the plant computer, the addition-al indications and alarms accepted by the staff. The staff's verification of this consisted of a review of the SNUPPS B0P computer system input / output summary (Revision 13).
(35), B (31) Actuation of valve component level windows' on the bypassed and inoperable status panel - The staff verified (through the review of drawings) that bypass indication for the accumulator valves occurs when the valves leave the full open position. (SER Sec-tion 7.5.2.2)
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