ML19326C678
| ML19326C678 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/27/1975 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Phillips J ARKANSAS POWER & LIGHT CO. |
| References | |
| NUDOCS 8004250493 | |
| Download: ML19326C678 (4) | |
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4 Distribution Docket NOV 2 71975 upc pg3 Iocal PDR ORB #2 PFarling KRGoller Docket No. 50-313 TJCarter f;
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ATIN: Mr. J. D. Pld11im Senior Vice Pr==Iamit Warga f
Production, Transrission, DEisenhut and Engineering hthy Sixth and Pine Streets
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Pine Bluff, Ad.ansas 71601 ACRS (16)
Gentlemen:
We are reviewing the Arkansas Zar1aar One, Unit 1 Eagpcy Core Cooling Systan reevaluation subnittals dated @ 21, July 9, August 8, August 22, and Septanber 9,1975, as well as Wical report BAW-10103, "BOCS i
Analysis of B&W's 177-FA Iowered-Iacp ?ESS," and have cone'In+d that the adr11tional information descrited in the enclosure is needed to continue Our revicW.
To enable us to maintain our review schedule, please provide the rr. quested information by Decerter 30, 1975.
Sincerely,
'Driginal Sigred by:1 Dennis L. Ziezana Dennis-S-fiswal,- Chief Operating Peactors Branch #2 Division of Beactor Licensing
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Form AEC 318 (Rev. 9-53) AECM 0240
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e Arkansas Power & Light Company cc w/ enclosure:
Horace Jewell House. Holms & Jewell' 1550 Tower Building Little Rock, Arkansas 72201 Mr. William Cavanaugh, III Production Deparcment Post Otfice Box 551 Little Rock, Arkansas 72203 Arkansas Polytechnic College Russellville, Arkansas 72801 O
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ARKANSAS POWER AND LIGHT CIF!PANY ARKANSAS NOCLEAR ONE, UNIT 1 DOCIETT NO. '50-313 Mumu 'EUR ADDITIONAL DEOR& TION 1.
It is the staff's position that Mode 1 should not be attempted as the primary method to control boron concentr'ation in the core during long-term cooling. The possibility of gas or steam entrainment in the decay heat suction nozzle can result in severe damage to the decay heat retoval punp.. Iong-tem heat.recoval requirements can exisu for long durations (days or nonths) after the accident and continuous operation of one train of the decay heat removal system is required.
In the event of a equipnent malfunction in this train, no method is available to retove the decay heat if the other train has been previously.
damaged. Therefore, implenentation' of mde 1 should ot be attempted since this action could resul:- in the decrease of required safety equignent.
'Ib verify that gravity draining for boron dilution for 2 de,2 is possible, provide the elevations of the piping and other canponents in the decay heat drop line frcm the hot leg nozzles through each of the trains to the reactor b'ilcling sump.
2.
With regard to the single failure analysis, the analyses did not consider the failure of any one of the four valves in the decay heat i
drop line and the resulting effect to EOCS perfonnance.
Expand your single failure analyses to include spurious' signals and the resulting consequences for all DD valves in the EXIS. Confirm that post-IDCA long-term cooling requirenents were considered (i.e., systems needed to linu.t boric acid concentration in the reactor. vessel).
3.
For a core ficoding tank (CFT) line break and an inadvertent closure of a valve in the unaffected low pressure injection line, the LPI-to-LPI crossover would be rendered ineffective.
Station Technical Specifications I
must require that power be disconnected and breakers locked open to LPI motor-operated valves dcwnstream of the LPI-to-LPI crossover (valves nomally open), and that a periodic test be performed to warn of abnormal leakage of the check valves in the LPI injection lines inside containment. These changes provide further assurance that abundant core cooling is available for a C?r line break and minimize the potential for a IDCA outside containment. Discuss the above concerns and subnit the required Technical @ ecification change if necessary.
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2-4.
It is noted that motor-operated valves CV1407 and CV1408 on drawing.
M-232, Rev.11, fran the BWST are shown nonna11y closed.
It appears that, assuning sufficient static head were available, the potential for a water hanmer when EXr is injected into a dry line would be rdM considerably if these valves were nomally left open. Discuss this concern and indicate your position in this matter.
5.
The operating methods to control boric acid concentration in the core during long-tenn cooling require operator action in areas where radiation dose levels may be excessive. Sirre operator actions may be delayed due to inaccessibility to manual valves, provide analyses of the boron concentration in the core as a function of time assuning the maximum possible time delay to implement the required systems.
6.
With regard to the partial loop analysis-Discuss the consequences of a break in an active cold leg of a.
the fully active loop.
b.
Two pump operation will not be pennitted unless an analysis is provided to support this node of operation. Canpare a break in the inactive cold leg to a break in the active cold leg.
Indicate and justify the worst-case pump status assumed at c.
the time of the IOCA (tripped vs. powered).
d.
Provide assurance tliat the PCP versus Break Size curve in BAW-10103 muld not be significantly, altered by eitbar node of partial loop operation.
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