ML19207A318
| ML19207A318 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 08/10/1979 |
| From: | Short T OMAHA PUBLIC POWER DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7908160439 | |
| Download: ML19207A318 (5) | |
Text
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Omaha Public Power District 4
1623 HARNEY a OMAHA, NEBRASMA 68102 e TELEPHONE 5 3 6-4000 ARE A CODE 402
August 10, 1979 Director of Nuclear Reactor Regulation ATTH:
Mr. Robert W. Reid, Chief Operating Reactors Branch No. 4 U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Reference:
Docket No. 50-26.
Gentlemen:
The Omaha Public Power District received your letter of July 26, 1979, requesting additional information regarding IE Bulletin 79-06B.
In reply, the attached response is provided.
Since rely,
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T. E. Short.
Assistant General Manager TES/KJM/BJH/sd cc:
LeBoeuf, Lamb Leiby & MacRae 1333 New Hanpshire Avenue, N. W.
Washington, D. C.
20036 A
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Responses to Requests for Additional Information Regarding IE Bulletin ilo.79-06B Fort Calhoun Uni t 1 Question 2 Revi s u your response to c nfirm implementa tion of procedures for na tural circula tion.
Als: review tne availability and use of instru-montatian to run: tor core condi tions under forced or natural circula-tion noues ci a;:ra tion.
Response
The operati ng procedures have been reviewed which confirm that methods for natural circulation cooling have been included and implemented.
Instruments available to monitor forced and natural circulation cooling include core exi t therrocouples, cold leg RTD's, and hot leg RTD's.
Addi tional instrumentation available to monitor forced circulation include loop-flow rates and pump amperage.
The procedures have been reviewed to assure applicable use of this instrucentation is included.
Questian c.b Rozise yo'zr response to co==dt to the requirements of paragraph 6.b as clar fiou bolcw una to use the sane cri teria for continued opera tion of Use r:ba r;: n g pu:;,a a s tnosc usca for the HPI pumps.
"Af ter 50! su coaling has Loen achieved, termina tion of high pressurc safety injection (HPI) o; era tion prior to 20 minutes is only permissible if it has baen deterndnad that continued operation would result in an unsafe cluat condi ticn,
e.g.,
a t taining pressure / tempera ture condi tions tha t co ul d jco;arazzo :csse. integri ty or that could have the potential for o;:eni ng the PORs or safe tu val ves so as to discharge wa ter or a two-phase fl uid consis ti ng of wa tor and s team "
_R_e_s o on s e Operating procedures and training instructions have been reviewed which ensure that the HPSI and charging punp systens wil' remain in operation until their intended functions are provided by other systens and which ensure that bleir operation will not result in an unsafe plcnt condition.
We concur with the revised speci fic guidance and have applied it to the hPSI and charging pump systems' operation.
Ouos tion 6.d Revise your respo:.sc to s um:.a ri za the addi tional infarca tion a nd ins tructions gi ven to opera to r.;
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Response
Toe operations staff has completed the discussion of the Three Mile Island incident as discussed in response to item 1 of IE Bulletin 79-063.
In addition, an operations memorandum was issued which discussed in detail the several confirmaroty indications which would aid the operator in analyzing plant cor.ditions of core coolant voiding or an open pressurizer relief valve.
Tne current series of lectures being administered to the rotating training snif t empnasizes the need to use all available sources of plant data to analyze plant transients.
Lectures are being adminis tered on small break loss of coolant accidents and natural ci rc ula ti on.
The lectures include expected plant performance and review tne expected plant instrumentation response.
The emergency procedures have been revised to include cautions anJ requirenents to check all available plant indications as an aid to transient operational decisions.
Ques tion 7 Revise your response to provi de assuranco that all locked safety re la tea valves are posi tioned and raintained in the appropriato posi ti on through all modes of opera tica.
Response
Locked in position safety related valves remain in the appropriate position during all modes of operations by exercising tne following netnods of control:
a.
Af ter each refueling or an extended outage, safeguards check-lists which include locked valves are completed by the opera-ti ons s ta f f.
The completion of these checklists initializes the system configuration.
b.
If maintenance activities are necessary as allowed by the Technical Specifications, a maintenance order is prepared.
By plant administrative procedures, the maintenance order becoces a vehicle by wrich control is maintained over any locked valves which ca. change position to accommodate the maintenance activi tie..
The maintenance order requires an operability cneck af equipnent when repairs are con-pleted which aids in assuring correct valve line-up.
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Certain valves are locked in position by means of a key c.
ope ra te d-swi tch.
If these valves are placed in an ab-normal configuration an alarm is initiated in the central control room complex and cannot be cleared until the subject valve is returned to its " safety" position.
d.
When the unit is changing modes of operations, operating procedures control the plant conditions at which valve alignrcents are performed.
Adnerence to these plant oper-ating procedures and the operating instructions which they reference help insure that safety related valves are maintained in thei r appropriate position.
Question ?
Revise your response to provide assur.uce of explicit notification of the status of safety rela ted syster:s when shift change occurs.
Response
Present procedures at Fort Calhoun Station provide methods by whicn equipment operability information is communicated between relieving shif ts.
The official control room log provides a continuous status of major pieces of equipment which are removed from service during each shi f t.
This log is available for review by all control room pe rs onnel.
The normal shif t t" mover procedures as specified in Station Standing Order 0-29 requi re that the shif t being relieved be briefed on any abnormal conditions in the plant, any special tests in progress and the status of maintenance activities in progress.
In addition a shif t supervisors log is maintained for turnover information between operating Shif t Supervisors.
This log is also reviewed by the operations supervisor and other station supervisors as necessary. A Night Order log is maintained and operations memorandums generated by the Supervisor-0perations and reviewed by the operations s taff to supplement -the turn-over information discussed above.
The alarm status check performed each shift aids relieving shifts in recognizing equipment which may be in an off-normal condition.
To further provide assurance of explicit notification of the status of safety related systems when a shi f t change occurs, the District will prepare a shif t turnover log to be completed by control room operating personnel and Shif t Supervisor.
This log should be ir use by September 1,1979.
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Ques tion 11 Revise your response to summarize your review of procedures for dealing wi th hydrogen in containcent.
Response
Operating procedures utilized, af ter a transient or accident potentially generating hydrogen gas, have been reviewed with regard to the plant's capability to:
a.
vent accumulated hydrrgen and/or otner noncondensible gases from tne reactor coolant system (RCS);
b.
de-gassi fy the reactor coolant; and c.
process the waste gas after removal from the reactor coolant.
The review was pe: formed assuming that all operations are to be performed outside the containment.
Additional operational flexibility may be available in some situations if entry into tne containment is allowed.
Sona transient or accident scenarios may also include the presence of significant quantities of radio-active fission gases along with the hydrogen in the reactor coolant.
The presence of the fission gases could limit containment entry and, in turn, the methods 'used to vent and process the hydrogen gac In addition the procedures governing the use of the hydrogen purge sys tem were reviewed wi th respect to the ability of the system to vent hydrogen accumulated in the containrent, and remove radioactivi ty from tne ef fluent by the use of iodine and particulate filtration.
Containment hydrogen concentration monitoring provisions were also re vi ewe d.
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