ML19248D012
| ML19248D012 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 06/22/1979 |
| From: | Reed C COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| FOIA-79-98 NUDOCS 7907300401 | |
| Download: ML19248D012 (8) | |
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Commonwealth Edison
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June 22, 1979
, 1 Mr. James G. Keppler, Director Directorate of Inspection and Enforcement - Rogion III.
U.S. Nuclear Regulatory Cc= mission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Subject Cien St,ation Units 1 and 2
.ddi.tf5nal Responses to II Bulletin Nos.79-06A and 79-06A (Revision No. 1)
NRC Dceket Nos. 50-295 and 50-304 References (a):
April 18, 1979 letter from James G.
Keppler to Byron Lee, Jr. transmitting IE Bulleti No.79-06A (Revision No. 1)
(b):
Apcil 27, 1979 letter frcm Cordell Reed to James G. Keppler responding to II Stiletin No.79-06A (Revision.No. 1)
Dear Mr. Keppler:
Reference (a) trans=itted II Bulletin No.79-06A (Revision No.1) regarfing a review of operational errors and system misalig=ents identified during the Three Mile Island Incident.
Referenca (b) contained Cc=onwealth Edison Ccmpany's responses to that Bulletin.
As a result of NRC Staff review of Cc cnwealth Edison's respenses of Reference (b), the NRC Staff requested additional infor=ation with regard to sulletin Items No.
2, 6, 7,
8, 10.c, 11 and 12.
Cc==cnucalth Edison's response to the Staff raquest is contained in Attachment 1 to this letter.
Please address any additional questions that you might have regarding this matter to this office.
Very truly yours, i
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Cordell Reed 559168 Assistant Vice-President attachment Director, Office of Inspection cc:
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ATTACEMENT 1 COMMONh'EALTH EDISON COMPANY RESPCNSES TO NRC REOUEST FOR ADDITIONAL INFORMATION WITH REGARD TO RESPONSE TO BULLETINS 79-C6A AND 79-06A (REVISION 1)
ZION STATICN UNITS 1 AND 2 NRC DOCKET NOS. 50-295 AND 50-304 The requests and responses below are numbered to correignnd to the Bulletin action items.
2.
Revise your response based on a thorough review of all transient and accident conditions based on insight gained f cm TMI-2 to (a) assure that action steps specifically warn of potential for voiding with a description of all instrumentation which =ight provide indication of potential or actual voiding, (b) specifically address operator actions, based on operational modes and instrument indicaticns discussed ~above, for terminating c'onditions tending to lead to void formation and (c) provide operators with guidance for e'nhancing core cooling given the unexpected condition of actual voiding in,the prinary system... Su==arice the results of this review incitding revisions to procedures.
Identify all instrumentation which might be utilized in void recognition; su=mari=e the review results and actions taken with regard to the natural circulation mode of operation and identify any aids provided to the operators to aid in recognition of voiding conditions.
RESPONSE
r Cu onwealth Edison c't.gany has joined an owners group of utilities with Westf 3 _ust plants to evaluate the events of the Three Mile -
Accident and to take corrective actions to prevent simil.
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The owners group has contracted with Westinghc.
n nunerous computer analyses in order to identity m;c:
a conditions so as to allow a detailed evaluation and re ision of actions during the course of a small LOCA.
The resultu of these analyses will be incorporated into Emergency Operating Procedures and all applicable training instructions.
Included will be necessary conditions for identifying and terminating voiding in the reactor vessel.
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2-It is expected that the results of the Westinghouse analyses will be available by mid-July and that the required procedural changes will be ec=pleted by Septe=ber 1, unless further required analyses are identified.
6.
Provide the date on which procedural revisions will incorporate the requirements of Action No. 6.
RESPONSE
Procedural revisions identified in Reference (b) have been implemented.
7.a Provide assurance that operating precedures and training instructions have been reviewed to ensure :hac Operators will not override autc=atic actions of engineered safe:v features, unless continued operation of engineered safe:v features will result in unsafe plant conditiens.
If thev have not been reviewed,
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of the review of operatLag procedures and tra5 5 q instructions, incorporating such =odifications as are necessary to cc= ply with Item 7.a of the Sulletin.
7.b Your response to Ita= 7.b appears to be inadequate with regard to the requirements of Ita= 7.b of the sulletin.
Provide assurance that operating procedures will be modified to keep high pressure injection and charging pu=ps in operation in accordance with the criteria specified in Item 7.b of the Bulletin.
Provide a schedule for ce=Pletibn of the review of operating precedures incorporating such =cdi"ications as are necessarv to ec= ply with Item 7.b of the sulletin.
7.c Your criteria for tripping reactor ecclant pu=ps is inconsistent with the provisions of Ite: 7.c cf the Bulletin.
Provide assurance that operating precedures will be =cdified to keep reacter cccian: penps in operation in accordance with Item 7.c cf the sulletin.
Provide a schedule for cc=pletien of the review cf operating precedures incorperating such =cdifications as are necessary to ec= ply with Ite= 7.c of the sulletin.
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7.d Identify those specific parameters other than pressurirer level identified for operator use in evaluating plant conditions and verify that these parameters have been included in appropriate operating procedures.
RISPONSE:
a) Response to Items 7.a,7.b and 7.c Cc=monwealth Edisen Cc=pany has joined an cwners group of Westinghouse plants to evaluate the events of the Three Mile-Island Accident and to take corrective actions to prevent sinilar such events.
The owners group has contracted with Westinghcuse to perform numerous cc=puter analyses in order to identify accident conditions so as to allcw a detailed evaluation and revision of actions during the course of a s=all LOCA.
The results of these analyses will be incorporated into Emergency Operating P ccedures and all applicable training instructions.
Included will be necessary conditions for terminating Safety Injection and for turning off reactor coolant pangs during 'the course of a LOCA transient.
It is expected that the results of the Westinghcuse analyses will be available by mid-July and that the required precedural changes will be c==pleted by Septe=ber 1, unless further required analyses are identified.
b) Response to Item 7.d With respect to pressurizer level, operators were instructed that a steam bubble could be fermed in the reacter pressure vessel while water level in the pressuricer was still indicated.
A caution statement is being added to the Emergency Operating Procedure s for a LOCA instrucuing the reactc: operaters to assess the existence of subccoling in the reactor vessel by ec= paring all het and cold leg temperatures cnd core exit thermoccuple temperatures to steam tabic saturation temperatures.
A control beard indication providing the operators a reading of degrees of subecoling is being develcped.
These actions are expected to be implemented by August 1.
The above ite=s will be ecvered in the periodic training received by all operators.
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8.
Please provide your' schedule for completing review of alig= ment requirements and procedures controlling manipulation of safety-related valves.
Submit a su= mary of the results of the reviews and any revisions necessary within two weeks after completion of the reviews.
LPM:
Determine whether the Technical Specifications require periodic surveillance of locked valves.
If not, add the following request for infor=ation.]
Also, review plant procedures and revise them as necessary to ensure that locked safety-related valves are subjected to periedic surveillanca.
Submit a s" - ary of the results of the review.
RESPCNSE:
A cc=plete review of the Engineering Safety Systems valve lineups is conducted at the conclusion of each unit re-fueling cutage.
All safety-related valves were verified by an
,cperator and a management person to be in the correct position.
System operating procedures and periodic surveillance testing procedures have been reviewed to ensure that proper controls are used when manipulating safety-related valves.
As a result of this review, no significant procedural deficiencies were dound.
In addition, the statien worked hand-to-hand with the resident NRC inspector to review actual and procedure valve alignments.
This inspection took place during the period April 30 to May 18.
Accessible valves along the main flow paths for the auxiliary feedwater, safety injection and residual heat removal syste=s were again physically checked during this inspection and verified to be in their correct position.
Procedure reviews perfermed showed thar there were no discrepancies.
Other safety-related systems were verified to be procedurally correct.
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The Zion Technical Specification does not require periodic surveillance of locked valves.
Therefere, a ecmplete review of safety-related systems was performed to identify the need for placing locking devices on manually operated valves.
Manual valves to be locked have been idqntified in the charging, safety injection, residual heat removal, condensate and auxiliary feedwater systems and the affected valves have been locked.
Other ESF systems are being reviewed at the present time.
Procedural changes are being initiated and full ec=pliance with station procedures will be effective by August 1,1979.
10.c Please describe the method used for transferring infor=ation about the status of safety-related systems at shift change.
RESPONSE
Shift relief is acec=plished in.accordance with ZAP 10-52-3, Shift and Relief Turnover.
The oncoming Shift Engineer and Shift Foreman review the Shift Engineer's log (a record of all sigp.ificant actions and events), outstanding surveillance for cut-of-service and failed safety-related equipment, and discuss plant conditions and evolutions planned or in progress prior to relieving the off-going shift.
With the use of both written and verbal information, the Shift Engineer /
Shift Fore =an has ccmplete knowledge of the status of safety-related equipnent at ti=e of relief.
In addition, a check list which idencifies safety-related equipment status is used by the reacter operators to ensure proper shift turnover.
The control recm superviser (Shift Foreuan) has the responsibility to review the turnover checklists and review the control boards for verification of equipment status, 11.
Provide assurances that notification of the NRC occurs within one hour and that an open continuous c.m.unication channel is estiblished and maintained with the NRC.
RESPONSE
In the event that the reactor is not in a controlled or expect 2d condition of cperation, the NRC will be nouified within one hour.
In afdition, the NRC recentiv 559173
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. had a dedicated phone line installed at Zicn Station for use in emergency situations.
This phone which may be used for i= mediate notification of the NRC will have an extension in the Station Cc_..and Center which will be used to set up the continuous cc=munications required by the NRC in an unusual event.
The persen assigned to ec==unicate messages over this telephone nor= ally will be the Zion Station NRC Resident Inspector.
Ecwever, prior to his arrival during an unusual event, the Engineering Assistant for Operations cr another management person en shift may be assigned by the Shift Engineer to =aintain this cL__unication link until the NRC Inspector arrives.
All information given over this telephone will be designated as unofficial and preli=inary until it is reviewed and approved by the C-__and Center.
12.
Your response cencerning methods and preceduras for dealing with hydrogen gas in the pri=ary system is too general.
Please provide =cre specific infc==ation concerning =etheds for re=cving hydrogen frem the primary system and indicate what documentation will be developed to-incorporate these methods.
RISPONSE:
The methods available for removing hydrogen frcm the prima.ry system are:
1.
Hydrogen can be stripped from the reacter coolant to the pressurirer vapor space by pressurizer spray operatica if the necessary reactor coolant pump is operating; 2.
Hydrogen in the pressurizer vapor space can be vented by pcwer-operated relief valves to the pressurizer relief tank and then to the contain-
=ent at=csphere via the rupture discs or pumped to the gas decay tanks; and 3.
Hydrogen can be removed frem the reacter ecolant system by the letdewn line and stripped in the volume centrol tank where it enters the waste gas system.
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. Procedures currently exist for remcving hydrogen thrcugh the pressuri=er or the volume control tank during nor=al operation.
These procedures are being reviewed as to their applicability during accident conditions and will be modified or new procedures written if required.
Additional methods for re= oval of hydrogen that =ay be identified by the Westinghouse owners Group will be thoroughly investigated and ingle =ented if applicable to Zion Station.
The procedural reviews and any applicable changes will be made by Septenber 1, 1979.
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