ML19312D416

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Responds to NRC 800310 Ltr Re Request for Addl Actions or Info Concerning Implementation of Category a Lessons Learned Requirements.Procedures for Implementing Reconnection of Pressurizer Heaters Completed
ML19312D416
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 03/13/1980
From: William Jones
OMAHA PUBLIC POWER DISTRICT
To: Reid R
Office of Nuclear Reactor Regulation
References
RTR-NUREG-0578, RTR-NUREG-578 NUDOCS 8003240373
Download: ML19312D416 (9)


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Omaha Public Power District 1623 HARNEY s OMAHA. NEBRASKA 68102 m TELEPHONE 5 36-4000 ARE A CODE 402 March 13, 1980 Director of Nuclear Reactor Regulation ATTN: Mr. Robert W. Reid, Chief Operating Reactors Branch No. 4 U. S. Nuclear Regulatory Commission Washington,-D. C. 20555

Reference:

Docket No. 50-285 Gentlemen: The Omaha Public Power District received a letter from the Com-mission, dated March 10, 1980, requesting additional actions orLin-formation concerning implementation of Category A Lessons Learned requirements at Fort Calhoun Station Unit No.1. The Commission's concerns are addressed in the enclosure forwarded herewith. Sincerely,

                                                      .i){k ~

W. C.' Jones Division Manager Production Operations WCJ/KJM/BJH/TLP:jmm Enclosure cc: NRC Regional Office LeBoeuf, Lamb, Leiby & MacRae 809 5

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  • p Enclosure 1 RESPONSE-T0 REQUEST FOR ADDITIONAL ACTION / DISCUSSION-
                                              . LESSONS' LEARNED . CATEGORY A Request:2.1.1
                          . Implement procedures for manual reconnection of pressurizer heaters prior. to restart of Cycle 6.

Action / Discussion Procedures for reconnection of the pressurizer heaters have been

                  . completed and added to the appropriate emergency procedures.

Request 2.1.3.a [(1) Document your connitment to power all valve position indi-

                  'cators from one vital bus at least until equipment qualification is -

complete'.

                          -(2)- Equipment must be operational prior to restart for Cycle 6.
                           - (3) Modify emergency procedures to reference new valve position indicators.
Action / Discussion (1) Prior to restart for Cycle 6, all valve position indicators for power operated relief and safety valves will be powered from one
                  .vi tal ' bu s. Power feed to one-half the indicators will be changed during the 1981 refueling outage.                         ,

(2): All position indicator equipment will be fully operational prior to startup, Cycle 6. (3) 'The acoustic indication of the status of the power. operated relief valve will be added to the symptoms section'of.the appropriate emergency procedures prior to startup. Request 2.1.3.b~ (1) Provide plans-and schedule for upgrading sub-cooling meter temperature inputs.

                          .(2) Discuss capability to monitor sub-cooling' margin with the plant computer (core exit thermocouple inp~u ts).

(3) -Modify emergency procedures-to reference new sub-cooling

                                                                               ~
                 . monitors.

(4) ' Equipment must be. operational prior to restart of Cycle 6. 1 g =

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                                           ,                                  Action / Discussion
                           .(1) The . temperature inputs' to the subcooling margin meters will be -

upgraded to~ the 300.to 7000F range during the 1981 refueling outage. (2) -The subcooled margin can be monitored with the. plant computer _ using the core-exit-thermocouples. It is proposed the saturation tem-

               - perature be calculated using the RCS pressure as an input. This tem-
               - perature will be compared to the average of eight core exit thermocouple temperatures and the degree of subcooling displayed to the operator.

(3) The subcooling marg'in meter and ' alarm indications will be-

included in- the appropriate operating instructions and emergency pro-
                 . cedures prior.to .startup.

(4) All equipment will be fullyfoperational prior to restart of

                 ' Cycle 6.-

Request 2.1.4 (1)' Revise your December 31, '1979, submittal to clearly identify

                 - essential and non-essential systems. ,

(2) ~ Provide the bases for your classification of essential systems. Action /Diseussion-Response to this request is provided in Attachment A.

                   -Reques t ' 2. I'. 6. a Final- system leak rates measured during~ the leak reduction program must be obtained prior to Cycle 6' power operation and reported shortly thereafter.                                     .

Action / Discussion Final system leak rate measurements will be obtained prior to Cycle 6 restart and the results will be reported within two (2) weeks fol-- lowing restart. Requesti2.1.7.b Your safety grade auxiliary feed flow transmitters and steam generator: level transmitters must be installed prior to startup.

                  - Action / Discussion 1 All' safety grade auxiliary feedwater flow transmitters and steam
                =-

generator level. transmitters will be~ installed prior to Cycle 6 restart,

               - providing the one ^1evel transmitter -that was returned to the vendor is.
               ^
                   . received in time for Cycle 6_ restart.. The transmitter is due to be-l-                   shipped . March -13, 1980.

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iRequest2.128.c Incorporate the procedures for-determining airborne radiciodine concentrations in occupied: areas following an accident. Procedures should reflect need to move sampler.between Technical Support Center and Control Room. Action /Diicussion 0perating Instruction OI-PAP-9, Procedure for Post Accident

          . Monitoring of Radiciodine in Occupied Areas, has been completed.

Instructions for instrumentation operation and personnel actions in the . . control l room andLTechnical Support Center area are includa'

           . Request 2.2.2.b (1). Revise Emergency Plan .to designate dedicated channels on the GAI-TRONICS for communication between the Technical Support Center and the Control Room and the Technical Support Center and the Emergency Control Center.

(2) Revise. Emergency Plan to designate an Emergency Duty Officer as the Technical Support Center Coordinator. (3)~ Commit to a date for operational condition for the computer-display of plant parametens inside the Technical Support Center. Action / Discussion (1)1 A revision to the Emergency Plan, section 5.3.1.1.1, has been initiated that'provides for channel 3 of the GAI-TRONICS system to be dedicated for communications between the control room, Emergency Control l

          ~ Center-(ECC), and the Technical Support Center (TSC).

(2) A revision to:the Emergency Plan, section 5.2.2.2.2.1.2.c, has been initiated to require that, upon a second Emergency Duty Officer  !

           '(ED0)' reporting to the ECC, one will remain at the ECC and the other                           l will report to the TSC to act as TSC Coordinator.

(3) ' Computer display of plant parameters in the TSC will be operational within 30 days of-plant startup following Cycle 6 reload.

                                                                                                           ^l 1

I

Attachment A-

    >          LRequest 2.1.4, Containment Isolation The Fo'rt CalhounlStation Unit No.1 reactor containment building is provided with an automatic. actuation system which operates containment penetration isolation valves (both to the open and to the closed posi-
                 -tion) to mitigate the consequences of an accident. The automatic systems are the Containment Isolation. Actuation Signal' (CIAS) and _ the Ventilation Isolation Actuation Signal (VIAS). It should be noted that VIAS is.

redundant to CIAS in that-it also generates a valve closure signal for certain isolation valves. closed by-CIAS; specifically, the containment purge and relief lines.

                        .The CIAS, as well as Safety Injection Actuation Signal (SlAS), is generated if either a Pressurizer Pressure Low Signal (PPLS) or a Con-
                 .tainment Pressure High Signal (CPHS) is generated by an accident con-dition'in the primary system and/or containment building.- The actual mechanism of isolation is designed to meet single failure criteria. The
                  .CIAS system consists of two redundant isolation channels (or trains) which are actuated by sensors, in a two-out-of-four logic, monitoring

, the primary system-and containment pressure. When the actuation logic l is satisfied, a signal is then generated which actuates the PPLS or CPHS "86"~1ockout relay which mechanically seals in the accident signal. The accident-signal in turn actuates- the emergency core cooling system and CIAS via an "86". lockout relay which mechanically seals.in the CIAS

               - control function. In addition, the Fort Calhoun Station Engineered Safety. Feature System is provided with an additional control relay whereby Channel A control may " reach across" and actuate Channel B e'q uipment and vice versa. This provides increased availability of safety equipment. . The CIAS train separation is maintained at the line
           -      isolation valves; Channel A will operate the A valve, and B the B valve
                 .(exceptions are dealt with later in the discussion).

l When the "86" CIAS relay is actuated, relays in the CIAS panel AI-

               .43A and AI-43B are de-energized, causing the isolation valves to assume Jtheir accident position.        In general, this electrically de-energizes a seal.in control' relay, which in turn de-energizes a solenoid valve which i

allows the air operated diaphram to go to zero pressure closing the l valve. The.previously discussed circuit is such.that when the accident signal is reset the valves remain in their accident positions. The i- valves may then be manually reset valve-by-valve (or pairs of valves as in.the case of certain cooling systems). No group resets exist. In

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addition, in general'when the accident signal is present manual re-positioning of the valves is blocked.- Exceptions will be dealt with in the following discussion of essential and non-essential ~ systems.

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V NON-ESSENTIAL SYSTEMS _ 4. u -{

                                                                ! System & Function             "

Isolation Valves .~ Reason for Isolation

    • ._1h : Primary System Letdown .
                                                                               ~
                                                                                                - HCV-204, TCV-202     ' Direct Connection with
                                              ~
                                                                                                                       -RCS

. -**.:2.- Roactor! Coolant Pump' HCV-241,--HCV-206 -Direct Connection .with Bleedoff RCS

                                                       *S 3 . S1 Tank Cooler Flow.
                                                                                   ~
                                                                                                --HCV-2983             ' Direct Connection with s
                                ~                                                                                        RCS-
:4. ReactoriCoolant: Sample HCV-2504A,LHCV-2504B Direct Connection with
                                                                                                                        -RCS
                                                         .5.    ' Containment Sump ~               HCV-506A, HCV-506B    Direct Connection with Containment Atmosphere
6. ~ Reactor Coolant Drain . HCV-500A, HCV-5008 Direct Connection with Tank' Discharge'. Containment Atmosphere
7. - Makeup.to Pressurizer _ HCV-1560A, HCV-1560B Potential Connection to Quench Tank RCS.
8. Demineralized Water - HCV-1559A, HCV-1559B Direct Connection with Supply. Containment Atmosphere
9. RCl Drain Tank Vent HCV-507A, HCV-5078 Potential Exposure to
                                                                                                                       'DBA Conditions 1
                                                         ~10. ? Pressurizer Quench -               HCV-509A, HCV-509B    Potential Exposure to
                                                                 -Tank Sample Line                                       DBA Conditions
                                                        -11. .RC Drain-Tank Sample.                HCV-508A, HCV-508B    Potential . Exposure to -

CBA Conditions L12. -N2 Supply . HCV-2603A,.HCV-2603B' Potential Connection with Containment Atmosphere

                                                                                                                                                 ~

113./N'Supplyto, 2 Pressurizer ~HCV-2604A,'HCV-2604B Potential Connection with Quench Tank- Containment' Atmosphere

                                                        .14. 1 Containment Radiation                PCV-742E .F, G H     Direct Connection to Containment Atmosphere L.

+ J15i t Containment. Relief' HCV-746A., HCV-746B - . Direct Connection to L < , Containment: Atmosphere n . 16. ! Service Air HCV-1749 (inboard Direct; Connection to-valves are manual Containment Atmosphere L closed) _h~ l5 -_ '. , f

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                                                    -          -                                  NON-ESSENTIAL' SYSTEMS (Continued)
                                 ~
                      " System & Function           Isolation Valves    Reason for Isolation
                .17; Containment tir; Purge'-       PCV-742A,' B,-C, D  Direct Connection to Containment Atmosphere
18. Nuclear Instrument HCV-467A, B, C, D Closed on Containment Detector Well Cooling Isolation
               - 19.-   SI: Leakage Cooler          HCV-425A, B, C, D   Closed on Containment Isolation 20.. Blowdown (SG)-                HCV-1387A/B         Closed on Containment HCV-1388A/B        . Isolation
21. Blowdown Sample (SG) HCV-2507A, B Closed on Containment.-

HCV-2506A, B. Isolation

               *HCV-2983 receives an isolation signal from both trains of. CIAS.

The remaining valves associated with this penetration are closed by-a safety injection signal and are part of the safety injection / leakage cooler- pressure protection: system.

            ' ** Control switch will reposition valve with. accident signal present; however, will immediately reclose when switch spring returns to
               -normal.

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4 The remaining valves discussed in this section'are provided with a

                        ~ containment isolation signal; however, in order to provide maximum flexibility, operation differs from the previous discussion. ' Those--

isystems . considered essential and the justification for. this designation - are.specifically0 called out within the text.

                                -1.   :The~ instrument air header valve PCV-1849 closes on low air
                                      . pressure (70:psig)andCIAS. With.a normal operating pressure
above accident: pressure, the air header isoleft in service unless low air pressure-is detected.- The availability of air
                                     - enhances reactor shutdown.       It must.be emphasized that air
                                      ~fai. lure will.in no way inhibit shutdown. -PCV-1849 fails open.

2.

The hydrogen purge system ^HCV-881, 882, 883A/C, 884A/C is required for~ operation ~1n a post-accident condition. The L supply and ~ exhaust, ~HCV-881~.and 882, are equipped with auto-matic valves inside containment only.- These valves are closed
                                       -by CIAS, but fail:open on loss 'of control power or air. The valve isolation function'is backed up by redundant locked
                                      ~ closed manual valves. 1The sample valves,-HCV-883A/C and HCV-884A/C, have a similar arrangement; however, the automatic valves outside containment, HCV-883A and 884A, fail closed and
                                      .are closed by.CIAS. Override switches are provided to over-
                                                                          ~             ~

ride the CIAS function. The system is used to detect and

                                      . remove hydrogen in a post-accident environment.
3. The auxiliary feedwater system (hhich is not directly con-nected to the RCS or containment atmosphere) HCV-1107A/B and 1108A/B are opened'by:CIAS and fail open.' 0verride switches-
                                     .are provided for post-accident valve positioning. Circuit modification to these valves will be dealt with under the
                                     . Auxiliary Feedwater Section of NUREG-0578. This is considered a,n essential system because it provides for decay heat re-moval.
4. The main feedwater' penetration isolation valve HCV-1385 and 1386 are motor operated valves which close on CIAS. These valves -fail "as~ is", but are connected to a vital 480 volt bus to ensure closing. -In addition, there are check valves 'in the system as redundant valves. This system-is.not directly connected to,the RCS or. containment. atmosphere. To enhance the ability ~to mitigate a small break LOCA, a design change is being evaluated to provide automatic isolation of HCV-1385 and HCV-1386 on.CPHS or SGLS, similar to the main steam isolation 4 valves. It should ~ be noted that decay heat removal' may always be accomplished by auxiliary feedwater. The availability of main feedwater will enhance accident response ability to
. remove-decay heat in'some accident situations. With an
                                     . a.ccident signal- present, if an attempt .is made to open: the
                                     ' valves manually, they will drive open then immediately back closed.
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5. ' The containment air cooling units' cooling water supply valves HCV-400A/C, B/D, 401A/C, B/07_402A/C, B/D, and 403A/C,-
                         ~ B/D are opened by CIAS and. fail open. :This is considered an essential system. This system functions to limit containment pressure...
6. The reactor coolant pump lube oil: cooler and seal cooler supply and. return line HCV-438A, B, C D close_on CIAS._ The valves inside containment (A and C) fail open. The valves have override switches to' open after CIAS to reinstate cooling water. 'The failure of valves or closure on CIAS-will not trip the reactor coolant pump motors.

The remaining penetrations not actuated by CIAS 'are those which are a_ssociated with shutdown or a different type accident. These systems are listed below.

                    -1. Safety injection - opens under accident signal. This is considered an essential system, which supplies borated water to the reactor core.
2. Containment spray - opens on CPHS and PPLS. This is con-sidered an essential system to limit containment pressure.
3. Shutdown cooling - locked closed,'it functions as part of the RHRS system.
4. Containment sump recirculation - part of ECCS actuates on RAS.

This is considered an essential system, 'since it functions as part of the post-accident heat removal system. 1

5. Main steam isolation valves - closed upon SGLS (Steam Gener-ator Low Signal) and CPHS (Containment Pressure High Signal)

~ part of closed system not in contact with RCS or containment

                         ' atmosphere. They function to mitigate a main steam line break
                        . accident.
                      ~

6.- Charging - does not isolate. This is considered an essential system that provides boric acid 'to the core. This system is not considered in the safety analysis, but helps assure plant safety.

7. Containment pressure monitoring penetrations (4 total) -

remain open, generate CPHS. They allow for monitoring con-tainment pressure.

The design' requirements of NUREG-0578 are presently satisfied, and i no changes' to the initiation scheme or to the circuit design are neces-- I sary.-. The ' deletion of HCV-438A, B, C, and D from CIAS closure is under evaluation; but this will not affect the isolation requirements of-
            .NUREG-0578.      Essential systems, identified above, are those which are not~ isolated on CIAS. All non-ess c tial systems are isolated.

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