ML112231554
| ML112231554 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 05/14/1981 |
| From: | Kaucher J Franklin Institute |
| To: | Beard J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML112231555 | List: |
| References | |
| CON-NRC-03-79-118, CON-NRC-3-79-118 NUDOCS 8105180284, TER-C5257-190 | |
| Download: ML112231554 (23) | |
Text
ENCLOSURE 4 TECHNICAL EVALUATION REPORT OVERRIDE AND RESET OF CONTROL CIRCUITRY INTHE VENTILATION/PURGE ISOLATION AND OTHER ENGINEERED SAFETY FEATURE SYSTEMS IOWA ELECTRIC AND POWER COMPANY
___________DUANE ARNOLD ENERGY CENTFR NRC DOCKET NO. 50-331 NRCTAC NO. 10180 FRC PROJECT 05257 NRC CONTRACT NO.NRC-03-79-118- FRCTASK 190 Prepared by Franklin Research Center Author J. E. Kaucher The Parkway at Twentieth Street Philadelphia, PA 19103 FRC Group Leader: J. Stone Prepared for Nuclear Regulatory Commission Washington, D.C. 20555 Lead NRC Engineer J. T. Beard May 14, 1981 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or Implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any Information, apparatus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.
Franklin Research Center A Divisionof The Franklin Institute Da I The Senjarnin Franklin Parkwa ,. Phila.. Pa. 19103 (215) 4.48-1000 N
-7 TER-C5257-190 ABSTRACT This report documents the technical evaluation of the design of electri cal, instrumentation, and control systems provided in the Duane Arnold Energy Center to initiate automatic closure of valves to isolate the containment.
The evaluation was .conducted in accordance with NRC criteria, based on IEEE Std 279-1971, for assuring that containment isolation and other engineered safety features will not be compromised by manual overriding and resetting of the safety actuation signals. It was concluded that the electrical, instru mentation, and control systems in Duane Arnold Energy Center partially con form with the NRC criteria.
iii
TER--C5257-190 FOREWORD This report is supplied as part of the Review and Evaluation of Licensing Actions for Operating Reactors being conducted by Franklin Research Center (FRC) for the U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Reactor Regulation, Division of Licensing.
The work was performed by FRC, Philadelphia, PA, under NRC contract No.
NRC-03-79-118.
iv
TER-C5257-190 CONTENTS Title Page Section 1
1 INTRODUCTION. * .. . . . .
. 2 2 EVALUATION
. * . 2 2.1 Review Criteria .
3 2.2 Containment Ventilation System Design Description . .
2.2.1 Generalized System Design . . . 3
. 3 2.2.2 Logic Circuits for Reset Seal-in and Trip 2.2.3 Individual Valve Control Circuits . 4 Containment Ventilation System Design Evaluation. 6 2.3 2.4 Other Engineered Safety Feature (ESF) System Circuits 7
2.4.1 Description of RER System Design 7' 2.4.2 Evaluation of Other ESF Systems Design . 7 2.4.2.1 RER System. .
2.4.2.2 Other ESF Systems 8 CONCLUSIONS. 16 3
.. 18 4 REFERENCES v
J00 Franklin Research nsauteCenter A Dision of The Frankin
TER-CS257-190 LIST OF FIGURES Title Page No.
11 1 PCIS Control Scheme 12 2 Typical PCIS Valve Control Circuits 13 3 RER Control Logic 14 4 Containment Spray Valve Control Circuit 15 5 Typical RER Valve Control Circuit vi
-OU Franklin Research Center A Dsaon of The Franadinisue
TER-C5257-190
- 1. INTRODUCTION Several instances have been reported at nuclear power plants in which the when containment ventilation/purge valves would not have automatically closed overridden or required because the safety actuation signals were either design blocked during normal plant operations due to procedural inadequacies, also deficiencies, and lack of proper management controls. These instances the containment isolation brought into question the mechanical operability of valves themselves. The U.S. Nuclear Regulatory Commission (NRC) judged these instances to be Abnormal-Occurrences (#78-5) and were, accordingly, reported to the U.S. Congress.
As a follow-up on these.Abnormal Occurrences, the NRC staff is reviewing of the electrical override aspects and the mechanical operability aspects 28, 1978, contain- ment purging for .all operating power reactors. On November Plant the NRC issued a letter entitled "Containment Purging During Normal and pressurized water Operation" Il]* to all boiling water reactor (BwR) 3, 1979 [2], the Iowa reactor (PWR) licensees. In.a letter dated January Duane Arnold Energy Electric Light and Power Company (IEL), the Licensee for On August 31,,1979 (3], IEL Center (DAEC), replied to the NRC generic letter.
to the NRC generic letter. On provided additional information pertaining provide additional March 28, 1980 [4], the NRC requested that the Licensee safety information concerning electrical bypass and reset of engineered May 5, 1980 feature (ESP) signals for DAEC. IEL made a partial response on electrical design, and
[5), which addressed only the containment purge valve analyzed their system in submitted a supplement on June 17, 1980 £6], which electrical
'terms of the NRC criteria for ESF equipment and presented compliance.
schematics, system diagrams, and electrical data to verify reviews the IEL The present technical evaluation report, which documentation, deals only with the design of the DAEC electrical, the containment ventilation instrumentation, and control (EI&C) components of isolation (CVI) and other engineered safety features.
of references, Section 4.
Numbers in brackets refer to citations in the list nklin Research Center AO d The Franklni Insatte dMSIn
TER-C5257-190
- 2. EVALUATION 2.1 REVIEW CRITERIA if the following The primary intent of this evaluation is to determine to all ESF equipment:
NRC staff criteria are met for the safety signals o Criterion 1. In keeping with the requirements of General Design
. Criteria (GDC) 55 and 56, the overriding* of one type of safety.
of actuation signal (e.g., radiation) should not cause the blocking (e.g., pressure) for those any other type of safety actuation signal valves that have no function besides containment isolation.
switches) o Criterion 2. Sufficient physical features (e.g., key lock adequate administrative controls.
are to be provided to facilitate status o Criterion 3. A system-level annunciation of the overridden when any override should be provided for every safety system impacted is active. (See NRC Regulatory Guide 1.47.)
design Incidental to this review, the following additional NRC staff criteria were used in the evaluatiok:
to initiate isolation o Criterion 4. Diverse signals.should be provided high of the containment ventilation system. Specifically, containment containment high pressure radiation, safety injection actuation, and of .safety injection (where containment high pressure is not a portion actuation) should automatically initiate CVI.
provided to o Criterion 5. The instrumentation and control systems be designed and qualified as safety-grade initiate the ESF should equipment.
Criterion 6. The overriding or resetting+ of the ESF actuation o
cause any valve or damper to change position.
signal should not other related ESF In this review, Criterion 6 applies primarily to criterion for containment isolation systems, because implementation of this based on the has been reviewed by the Lessons Learned Task Force, valve repositioning recommendations in NUREG-0578, Section 2.1.4. Automatic in order to
- Override: the signal is still present, and it is blocked perform a function contrary to the signal.
circuit is being cleared in
+Reset: the signal has come and gone, and the order to return it to the normal condition.
JiuUFranklin ResearchInsute Center A Di.v of The Franiain
TER-CS257-190 The containment isolation is not involved.
upon reset may be acceptable when reset will be determined on a case-by-case acceptability of repositioning upon upon system function, design intent, basis. Acceptability will be dependent and suitable operating procedures.
2.2 CONTAINMENT VENTILATION SYSTEM DESIGN DESCRIPTION 2.2.1 Generalized System Design for the Duane Arnold The Licensee has indicated that "The circuitry was-designed in accordance with IEEE Energy Center (DAEC) safety systems the time of design and the version Standard 279-1968 or 1971, depending upon Also, .recent modifications have been of-the standard which governed" [6].
control circuitry in 6rder to made to the containment ventilation system comply with the six NRC criteria.
2.2.2 Logic Circuits for Reset Seal-in and Trip identified as the primary The DAEC design consists of.two ESF trains, which can cause isolation of the containment isolation system (PCIS),
A controls the inboard containment
.containment purge and vent systems. Train purge and and Train B controls the outboard purge and vent isolation valves, by a different electrical bus.
vent isolation valves. Each train is powered The isolation signals for each train are:
- 1. Automatic Isolation Signals (1 of 1)
- a. high reactor building exhaust radiation high fuel pool exhaust radiation (1 of 1) b.
pressure (2 of,2).
- c. high drywell (2 of 2)
- d. low reactor water level
- 2. Manual Isolation Manual No system level manual isolation is provided. for via manual switches isolation is accomplished individual purge and vent valves.
isolation parameter operate contacts, Trip relays associated with each (Figure 1), to provide power to two arranged in series-parallel configuration JULA Franklin Research Center A DC .si o The Frankin1insanae
TER-CS257-190 slave relays (K23/K24 :and K63/K61) in each train via a seal-in relay (K23/K24).
contact paralleled by a momentary reset switch contact. The slave relays, circuits in when energized, close contacts in the individual valve control and vent series with the local control switch and solenoid, allowing purge relays in each isolation valves to be opened. A contact from one of the slave paralleled with train performs the seal-in function.. Trip relay contacts are a keylock-controlled switch parameter override contacts that are operated from switches also actuates provided for each isolation parameter. Each of these signal has an annunciator circuit to indicate that a specific protection been bypassed.
all trip parameters On system startup, with slave relays deenergized and will below their setpoint, momentary closure of the circuit reset contact the seal-in circuit energize the slave relays which, in turn, will complete around the reset contact and close contacts in series with associated pilot solenoids.
power to When the level of an isolation parameter exceeds its setpoint, slave relays the slave relays is interrupted via the trip logic network. The slave relay are deenergized and both seal-in and valve control circuitry a trip signal, contacts are opened. Slave relays can be reenergized following bypassed and the reset only after all signals .are cleared or individually switch manually positioned.
2.2.3 Individual Valve Control Circuits vent and purge valve control The torus and drywell, inboard and outboard, of the trip logic network circuits (-Figure 2) receive power from the output the slave relays).
(i.e., these control circuits are in parallel with only when Consequently, the pilot solenoids for these valves may be energized condition required for all trip signals are cleared or bypassed (the same contacts are provided in slave relay energization). In addition, slave relay series with each valve operator pilot solenoid.
valve also includes a three The control circuit for each vent and purge to auto, control switch. There are position (close-auto-open), spring return UFranklin Research Center A Divie d The Fraiidn Insmma
TER-CS257-190 two sets of switch contacts (open and close) in each valve control circuit.
which The opening contacts are series contacts paralleled by seal-in contacts, are closed when the pilot solenoid auxiliary relay is .energized. The closing contacts are in series with the pilot solenoid and auxiliary (seal-in) relay.
With the valve control logic circuit energized, the slave relay contacts in each valve control circuit are shut. The valve(s) may now be opened by momentarily placing the particular valve control switch in the *open' the position. This causes the valve opening contacts to close, energizing seal-in pilot solenoid and auxiliary relay which, in turn, closes the contacts. The valve will then remain open until either the valve control switch is placed in the "closed" posi.tion or an isolation signal is received.
The individual valve control circuits for the torus and drywell vent bypass valves (Figure 1) are the same as those for the torus and drywell purge and vent valves. These valve control circuits may, however, receive power from either the output ofthe trip logic circuit or directly from AC control of power power, bypassing the trip logic network. When this bypass mode bypass valve supply is selected, only one of the two, torus or drywell, on the position control circuits can be supplied power at one time, depending in the individual valve of the bypass switch. Since slave relay contacts solenoid, neither the control circuit are connected in series with the pilot the slave relays are pilot solenoid nor the valves can be opened when deenergized (i.e., a trip signal exists and is not bypassed).
The valve control circuits for the torus and drywell nitrogen makeup and purge valves with the valves (Figure 2) are the same as those for the vent pressure is greater addition of series contacts which open when the drywell inerting than 1 psig. These contacts provide automatic control of nitrogen the containment.
seal valves The valve control circuits for the purge to recirculating trip logic network. For these (Figure 2) receive power from upstream of the permissive circuit in lieu valves, the slave relay contacts operate in a valve circuits. The valve of directly activating contacts in the valve control low-low water level permissive relay is in series with two sets .of reactor JFrnklin Research Center A DMsan at The Franbin Imoute
TER-C5257-190 contacts, a parallel circuit providing reset and seal-in contacts, and the slave relay contacts. The permissive relay contacts in the purge to recirculating seal valve control circuits operate in series with the valve manual pilot solenoid/seal-in relay and the parallel configuration of switch/seal-in relay contacts.
2.3 CONTAINMENT VENTILATION SYSTEM DESIGN EVALUATION No instances were found where the overriding of one type of safety
-actuation signal (e.g., drywell high pressure) causes the blocking of any other type of safety actuation signal (e.g., reactor low level) for those valves that have no function besides containment isolation. Therefore, it was concluded that NRC staff Criterion 1 has been satisfied in the PCIS at DAEC.
Override switches provided (GE Model CR2940 Form UN200D) are keylock-type switches and will support adequate administrative controls. Therefore, it was concluded that NRC staff Criterion 2 has been satisfied in the PCIS at DAEC.
Each override switch provides one contact which energizes an amber light operator for each in the control room to display the bypass condition to the in the override position.
individual trip parameter when the switch is placed of isolation logic are Also, the four override switches in each division connected to a common annunciator window in the control room, such that any in an one of the four key switches placed in the override position results it was concluded alarm which requires operator acknowledgment. Therefore, at DAEC.
that NRC staff Criterion 3 has been satisfied in the PCIS The four isolation parameters listed in Section 2.2 will automatically is no radiation initiate containment ventilation isolation. However,,there The two radiation detector that monitors the primary containment atmosphere.
and the reactor detectors which initiate PCIS monitor the fuel pool area building. Therefore, Criterion 4 is not satisified.
systems, The Licensee has indicated that the instrumentation and control designed in accordance including detectors, provided to initiate the PCIS are Therefore, NRC staff with IEEE Std 279 and use Seismic Category I equipment.
Criterion 5 -is-satisfied in the PCIS at DAEC.
JUPU rknlin Research Center A Dison al The Frankli Instumie
TER-C5257-190 The overriding or resetting of any actuation signal will not cause any valve or damper to change position. This is accomplished by the use of seal-in of reset relays and contacts at the equipment level and also by the provision and override controls at the accident parameter level. Therefore, it was concluded that NRC staff Criterion 6 has been satisfied in the PCIS at DAEC.
2.4 OTHER ENGINEERED SAFETY FEATURE (ESF) SYSTEM CIRCUITS To provide a complete evaluation of the ESF system circuits, a general for review of all ESF system circuits and an in-depth review of the circuit the residual heat removal (RER) system was conducted.
2.4.1 Description of RER System Design Initiation signals, Phase A and Phase B, are provided for all RER trains, engineered safety feature equipment on each of two separate electrical A and B. Each train consists of automatic inputs processed through relay The logic circuitry to actuate a relayed logic component actuation system.
initiation signals for each electrical train are arranged to provide automatic initiation upon either of the following signals:
- 1. High drywell pressure (1 of 2 taken twice)
- 2. Reactor low water level (1 of 2 taken twice) configuration The contacts from the control functions are in an "or gate" and contact as and the logic circuit is provided with a seal-in relay (K9) well as a reset control (Figure 3).
and automatic Individual pump and valve control circuits have both manual indication for run control schemes for ,start-stop or open-close as well as an status or position.
2.4.2 Evaluation of Other ESF Systems Design 2.4.2.1 RHR System No instances were found where the overriding of one type of safety actuation actuation signal causes the blocking of any other type of safety i.J'u~ Franklin Research Center ADMsion al The Frabnii isolue
TER-C5257-190 isolation.
signal for those valves that have no function besides containment However, ten ESF actuated valves (MO-2000, MO-1902, MO-2005, MO-1932, 10-2007, 10-1934, 140-2006, MO-1933, MO-2001, and MO-1903), which have functions in addition to containment isolation, are provided with control circuitry that allows the bypassing of automatic ESF actuation (see Figures 4 and 5). These valves are normally shut on RHR automatic initiation. They may keylocked be opened through the use of two or three manual switches, a local control switch (42/CS, Figure 5), and either S17 or S17 and 518 (keylocked) depending on the presence of an automatic intiation signal and low reactor vessel shroud level (see-Figure 4). Following these manual actions, the automatic initiation of RHR will not cause these valves to close. Although not a literal violation of Criterion 1, this situation has been identified for NRC staff evaluation with respect to acceptability.
Two of the three switches required to bypass the RER valves identified above (S18 and local control switches) are keylock-type switches and will support adequate adminstrative controls. In addition, system level 3
annunuciation of this condition is provided. Consequently, Criteria 2 and 3 do not apply to other are satisfied for these ten valves. Criteria 2 and RHR valves.
Criterion 4 does not apply to the RER system.
systems The Licensee has indicated that the. instrumentation and control in accordance with IEEE Std provided to initiate the RHR system are designed Criterion 5 is 279 and use Seismic Category I equipment. Therefore, NRC staff satisfied in the RHR system at DAEC.
cause The overriding or resetting of any RHR actuation signal will not was concluded that NRC any valve or damper to change position. Therefore, it staff Criterion 6 has been satisfied in the RER system at DAEC.
2.4.2.2 Other ESF Systems equipment items at Equipment level bypasses are provided for several will prevent DAEC which, if actuated following one safety actuation signal, to take its a second safety-actuation signal from causing the equipment 1U.1Franklin Research Center A DmWW d The Franadin Instte
TER-CS257-190 post-accident position. This equipment, however, serves functions other than containment isolation. These valves are identified below:
- a. Reactor Water Sample Valve (Inboard) SV-4639
- b. Reactor Water Sample Valve (Outboard) SV-4640
- c. N 2 Supply Isolation Valve (Inboard) SV-4371B
- d. N2 Supply Isolation Valve (Outboard) SV-4371A
- e. Loop A Containment Atmosphere Monitor System Isolation Valve SV-8101A to SV-8110A
- f. Loop B Containment Atmosphere Monitor SV-8101B to SV-8110B System Isolation Valve been Although not a literal violation of Criterion 1, this situation has identified for NRC staff evaluation with respect to acceptability.
Operation of these bypasses is controlled by keylock switches and their activation is annunciated. Consequently, NRC staff Criteria 2 and 3 are satisfied for these eight valves.
Criterion 4 does not apply to ESF valves other than PCIS valves.
The Licensee has indicated that the instrCmentation and control systems are designed in accordance with IEEE Std 279 and use Seismic Category I equipment. Therefore, Criterion 5 is satisfied.
Several equipment items not related to the PCIS or RHR systems will, as currently designed, move to their normal, pre-accident, position upon to these safeguard signal reset. DAEC has provided proposed modifications control circuits (Attachment 3 to Reference 6) which will, when implemented during the 1981 refueling outage, prevent such repositioning upon reset. FRC has reviewed these system modifications and concurs that following their move to their implementation Criteria 6 will be satisfied. The valves which normal, pre-accident, position upon safeguard signal reset are:
- a. Reactor Recirculation Pump Discharge Bypass Valve (MO-4629)
- b. Reactor Recirculation Pump Discharge Bypass Valve (M0-4630)
- c. Auto Depressurization Valve (SV-4400)
- d. Auto Depressurization Valve (SV-4402)
- e. Auto Depressurization Valve (SV-4405)
JJJU Franklin Research Center A DMsion oi The Franin saute
TER-CS257-190
- f. Auto Depressurization Valve (SV-4406)
- h. Steam Line Drain Isolation Valve (outboard) (SV-2212)
- i. Consensate Pump Discharge Isolation Valve (SV-2235)
- j. Steam Line Drain Isolation Valve (inboard) (SV-2211)
- k. Consensate Pump Discharge Isolation Valve (SV-2234)
- 1. Steam Line Drain Isolation Valve (SV-2410)
- m. Consensate Pump Discharge Isolation Valve (SV-2435)
- n. Steam Line Drain.Isolation Valve (SV-2411)
- 0. Consensate Pump Discharge Isolation Valve (SV-2436)
- p. Air to Steam Pressure Reducer Valve (SV-2033)
- q. Air to Steam Pressure Reducer Valve (SV-2034)
- r. Air to Condenser Discharge to Suppression Pool on RCIC (SV-2037)
S. Air to Condenser Discbarge to-Suppression Pool on RCIC (SV-1966)
- t. Air to Steam Prbssure Reducer Valve (SV-1963)
U. Air to Steam Pressure Reducer Valve (SV-1964)
.H rankfin Research Center A Di.on of The Franklin Insatute
A Notes:
- 1. Seal-in contact
- 2. Valve solenolds energize to open valves B
>i P5 a.
co.
PCIS Logic SV 4300 SV 4310 Torus Vent Drywell Vent Bypass Bypass
-.1 to 0
Figure 1. PCIS Control Scheme I I
A in SV4300. SV4302 SV4312 Recirc. Valve SVIO04A SV4307, SV4308 SV4313 Permissive SVI804B SV4301, SV4303 Totual/rywell Purge To RecirculatinG SV4300, SV4311 Nitrogen Makeup, Seal Valves ToruelDrywell, Inboard &Outboard Vent and Air Purge Valves LA t'
.o n
Figure 2. Typical PCIS Valve Control Circuits I, I
9 wll A BA a~ow BK9 Pressure - Level High Rx Low A Drywell B A Water B Pressure Level K1O .
Test Test Reset W
K 9 >K73 K94 K10 K61 168 RHR Logic Auto initiation In to Figure 3. RIlR Control Logic
- 0
- - --- c
- 3r s17 r HI Drywell Pressure
~. HI Drywell Pressure vel S18
.K59 A
En La Figure 4. Containment Spray Valve Control Circuit
CLOSE OPEN I
CLOSE OPEN 0~I LS = LS L. LS r
.42-C (Key Locked)
K61 K61 K59 j(58 LS 42-C b
42-0 i
Valve Operator In w
0A (MO-2000, MO-1902; MO-2005. MO-1932, MO-2001 &
MO-1903)
Figure 5. Typical RHR Valve Control Circuit
TER-CS257-190
- 3. CONCLUSIONS The EI&C design aspects of ESF systems for Duane Arnold.were evaluated using staff design criteria.
. It is concluded that the PCIS circuit design at DAEC satisfies the NRC staff criteria for containment ventilation and purging operation with the exception of Criterion 4. Satisfaction of Criterion 4 will require that a radiation detector which monitors containment (i.e., drywell or torus) activity be provided and used to automatically initiate primary containment isolation.
Other ESF System Circuits
- 1. RER System The RER circuit design at DAEC satisfies the NRC staff criteria with the exception of Criterion 1 for ten valves which have functions in addition to containment isolation. These ten valves (listed in Section 2.4.2.1) may be required to provide containment spray for pressure control of the containment atmosphere in an accident environment. Opening of the valves in question requires multiple switch (keylock-type) operation, and system level annunciation is provided. In view of the possible operational requirements, administrative controls, and annunciation, FRC concludes that no modification to the RHR control circuit design is necessary.
- 2. Other ESF Systems The eight valves listed in Section 2.4.2.2 satisfy the NRC staff criteria with the exception of Criterion 1. However, because of operational requirements, these valves have functions in addition to containment isolation (i.e., post-accident reactor water sampling, nitrogen purge, and containment atmosphere sampling). Bypass'of ESF actuation signals is via a keylock-type switch and is annunciated. In view of the operational considerations, administrative controls, and annunciation provided, FRC concludes that no modification to these valve control circuits is necessary.
In the case of the 21 valves which will return to their normal, pre-accident, position upon safeguard signal reset, it is concluded that.
staff criteria will be satisfied upon completion of the circuit modifications identified in Attachments 2 and 3 to Reference 6.
-16 JUIFranklin Research Center A Don df The Frnidn inliut
TER-C5257-190 However, until the modifications are completed, appropriate administrative controls must to instituted to ensure that all operators are aware of this condition and operational procedures are established which ensure that these valves remain in their post-accident position upon system reset.
' Franklin Research Center A DviAon of The Frand InsMute
TER-C5257-190
- 4. REFERENCES
Subject:
Containment Purging.During Normal Plant Operation 28-Nov-78
- 2. L. Liu (IELPCO)
Letter to T. Ippolito (NRC)
Subject:
Containment Purging During Normal Plant Operations Iowa Electric Light and Power Company, 03-01-79
- 3. L. Root (IELPCO)
Letter to T. Ippolito (NRc)
Subject:
Containment Purging During Normal Plant Operations Iowa Electric Light and Power Company, 31-08-79
- 4. T. Ippolito (NRC)
Letter to D. Arnold (IELPCO)
Subject:
Request for Additional Information - Containment Purge System Duane Arnold (TAC 10180)
NRC, 28-03-80
- 5. L. Root (IELPCO)
Letter to T. Ippolito (NRC)
Subject:
Additional Information Concerning the Electrical Design of the Containment Purge Valves Iowa Electric Light and Power.Company, 05-05-80
- 6. L. Root (IELPCO)
Letter to H. Denton (NRC)
Subject:
Electrical Aspects of Engineered Safety Features (ESF) and ESF Reset Controls Iowa Electric Light and Power Company, 17-06-80 i Frnkin Research Center A OMcn of The Franklin Insotue