ML20033D191
| ML20033D191 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 12/01/1981 |
| From: | Geier J ILLINOIS POWER CO. |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| REF-SSINS-6820 IEB-79-27, IEB-80-06, IEB-80-6, U-0355, U-355, NUDOCS 8112070349 | |
| Download: ML20033D191 (7) | |
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fggg_93y_g ILLINDIS POWER 00MPANY 500 SOUTH 277H STREET. DECATUR, ILUN01s 62525 December 1, 1981 4
Mr. James R. Miller, Chief Q'
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Standardization & Special Projects Branch pv O
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Division of Licensing 1 u., )g g1 Office of Nuclear Reacter Regulation 78
<.,,%8/g U. S. Nuclear Regulatory Commission
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Washington, D.C 20555
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Dear Mr. Miller:
fj Clinton Power Station Unit 1 Docket No. 50-461 The attached material represents responses to issues which were discussed with Messrs Ernie Rossi and Rick Kendall during a meeting on November 30, 1981.
Illinois Power Company considers these to be adequate responses to the following issues:
IE Bulletin 79-27 IE Bulletin 80-06 Control System Failures Sincerely, L_., Ib L
J.D. Geier Manager, Nuclear Station Engineering Attachments cc:
J.H. Williams, NRC Clinton Project Manager H.H. Livermore, NRC Resident Inspector R. Kendall, NRC ICSB p'.p{e p
t Vsg 8112070349 811201 PDR ADOCK 05000461 A
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I Issue
Title:
Response to IE Bulletin 79-27 Issue:
The Bulletin asks for a review of Class IE and non-Class 1E buses to assure that ability to achieve cold shutdown is not impaired.
To perform this review, we suggest the following:
Identify all control (non-safety grade systems) which are used to achieve cold shutdown.
These systems include any alarms / indications which are used for shutdown.
Examine points where these systems are common (i.e., breakers, 4
power sources, inverters, etc.) with other systems as defined in Part a.
Postulate worst failure and anticipated operator. actions.
Is the normal path to cold shutdown still available?
If not, are alternate paths to achieve cold shutdown available?
4 The information requirements of NRC review are as follows:
Identify control systems used to achieve cold shutdown.
Bus information for the systems defiucd in Part a.
Identify common points (i.e., breakers, power sources or inverters, etc.) and resultant status of these systems given the worst common point failure.
Response
In response to this concern, Illinois Power has initiated a detailed review and analysis of the Clinton. power sources.
i Tables are being developed listing instruments and control devices on'cach power source, alarm indications and the effects.
from loss of-the power source.
Illinois Power will commit to provide the results of _ this review 4 months prior to fuel load
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and to impicment design modifications if any effect is found which has an adverse impact on safety. _ Illinois Power will implement any design changes found necessary as a-result of this review prior to startup,after the-first refueling.
outage.
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l Issue
Title:
IE Bulletin 80-06, Engineered Safety Feacure (ESF Reset Controls).
Issue:
-Automatic reset of safety systems logic following the
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return to normal of the initiating signal must be reviewed in accordance with IE Bulletin 80-06.
Response
A review of system schematic level drawings of Engineered i
Safeguard Feature (ESF) functions (ECCS,.RHR, W34, RCIC) was performed to determine their compliance to IE bulletin 80-06.
l The conclusions of this review are as follows:
1 1.
BWR's do not have an "emerp'ency mode" per se.
For l
clarification purposes an-emergency mode" is considered to be an abnormal plant condition in this review.
2.
No initiating logic will automatically reset upon the return'of the initiating signal to normal.
A " seal" is provided on all initiating logic.-
- 3. - A manually operated system level reset cannot occur unless the-cause of-the initiation has-been cleared.
-A deliberate operator-action is. required to accomplish manual system level reset.
4.
Upon a deliberate operator initiated system level-manual-reset, each. system' status is as follows:
a)
HPCS All acutated equipmentsLremain in their abnormal
' condition (e.g., HPCS pump running, injection valve open).
A manual operator action at the component.
level is requiredito change state of the actuated equipments.
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i Resporise :
a IIPCS Diesel Generator A system level reset of the ESF actuation signal will not~ shut down the diesel generator.
A manual operator action is regul_ed to shut the engine off.
However a system level reset does restore all of the protective trips provided for diesel generator protection (i.e., high jacket water temp, low lube oil press. reverse pouer, loss of excitation, overcurrent) which are blocked during an abnormal condition.
If any of these protective trips are present at the time of system level reset, the diesel generator will trip and a lockout will occur.
b.
LPCS All actuated equipment remain in their abnormal condition.
A component level operator action is required t. change state of actuated equipments.
c.
ADS All actuated valves (air operated) return to their normal condition hence changing state.
All ADS solenoids de-energize in its own division, closing the ADS valves (see Note 1.)
d.
SRV All actuated equipment remain in their abnormal condition.
c.
RHR All actuated equipment remain in their abnormal condition (e.g. pumps, injection valves, etc.)
They have to manually signalled closed at the component level.
f.
RCIC All actuated equipment remain in their abnormal condition.
The inboard / outboard isolation valves and the pump suction valve from the suppression pool are exceptions to this.
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MSIV i
All MSIV remain in their abnormal condition (i.e., closed). A manual operator action is required for each valve to change its state.
A review of B0P safety-related system schematic level drawings will be per formed to determine their compliance to IE Bulletin 80-06.
Illinois Power Company will commit to provide the results of this review 4 months prior to fuel load and to implement design modifications if any effect is found which has an adverse impact on safety.
Illinois Power Company will implement any design changes found necessary as a result of these reviews prior to startup after the first refueling outage.
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Issue
Title:
Control System Failures Issue:
IE Information Notice 79-2_2 This notice is concerned with the effect on plant safety analysis given control grade systems are exposed to environments caused by rupture of high energy lines.
To respond to this concern, the following is proposed:
Trace all high energy piping systems and identify the rooms / areas in which the systems identified in Attachment 2 are located.
Limit the breaks to areas where more than one of the systems are in the same vicinity.
Postulate resultant state of the reactor as a result of failing those systems.
Are Chapter 15 events bounding?
If yes, analysis is complete.
If no, perform analysis to identifj any increase in the consequences (peak clad temperature, peak containment pressure, peak suppression pool temperature, and radiological release) of any SAR event.
Common Power Source /Gensor Failures This request asks that a review be conducted to de7.onstrate that any single electrical failure (such as loss of power supply, short circuit, open circuit, or sensor failure) in control systems will not result in multiple electrical failures of control systems.
If multiple failures can exist, assurances must be made that a transient or accident resulting from this failure is not more severe than those in the plant safety analyses (Chapter 15).
To respond to this request, the following is suggested:
Create a list of all control systems and indicate those whose failure may irapact reactor pressure, reactor water level, or critical power ratio.
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i Identify any common power sources (two or more systems) and common sensors from this list of systems whc,se failures might impact the reactor.
Postulate the failure of each case in b and define an event scenario.
Evaluate cach scenario and determine if the existing Chapter 15 events are either identical or bound the postulated failures in c.
The information requirements for NRC review are as follows:
IE Information Notice 79-22 Identify credible breaks as defined in work scope.
Determine resultant states of sysmams as a result of these failurcs.
Common Power Source / Sensor Failure A copy of the GE elementaries for the GE systems on the attached list, marked up with the AE bus information.
Bus tree information from the elementaries back to the top level one line drawing.
This information could be in the form of sketches or lists.
Determine resultant states of the BOP systems given the worst sir.gle failure.
Response
In response to this concern, Illinois Power has initiated a review to determine whether high energy line breaks or single electrical failures could have an effect on any control system and to investigate the impact of failure of the applicabic syctem on the Chapter 15 safety analyses.
Illinois Power will provide the results of this review 4 months prior to fuel load and implement design modifications if any effect is found which has an adverse impact on safety.
Illinois Power will implement any design changes found necessary as a result of this review prior to startup after first refueling outage.