ML20031C116
| ML20031C116 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 08/30/1963 |
| From: | Bryan R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| References | |
| NUDOCS 8110060556 | |
| Download: ML20031C116 (3) | |
Text
Do Not Remove, UNITED STATES ATOMIC ENERGY COMMId3MSE AUTHORITY F HAZARDS ANALYSIS BY THE RESEARCH AND PO'a'ER REACT 07 SAFETY BRANCH DIVISION OF LICENSING AND REGULATIO1 IN THE MATTER OF i
YANKEE ATOMIC ELECTRIC C0!?ANY PROPOSED CHANGE No. 39 DOCKET h0. 50-29 Introduction Pursuant to the provisions of Section 50.59 of the co==ission's Regulations, Yankee Ato=ic Electz.c Co=pany in Propesed Change No. 39, dated June 28, 1963, requested authorization of revisions of certain sections of the Plant Maintenance Instructions vhien are 'ncorporated by reference as part of the Technical Specificatiers.
These revisions vould provide for a number of changes in the Maintenance Instructions in the light of Yankee's experience in operating the facility and the con-ditions which vill exist during the Core III refueling operation.
Discussion The revisions requested in Proposed Change No. 39 are for the nost part of an administz ative or a minor nature, and vith two excepcions, are acceptable fro = a safety standpoint in the for Y.nkee has proposed.
'n'e have discussed with Yankee the desirability of re:aining the require ent regarding neutron monitoring during fuel element movement into storage which is presently contained in Condition 6 of Mt.intenance Instruction 506E2.
It appeared to us that a si=ilar conditien should be provided ia the revised version of Maintenance Instructica 506E2.
Yankee has reviewed thic matter end has proposed that Condition 5 be revised to read:
8110060556' 630030 PDR ADOCK 05000029 p
, "S.
Storage is available in the fuel transfer pit for spent fuel assemblies and for fresh fuel.u aquired. The neutron count rate in the pit will be monitcred whenever fresh fuel is being loaded into a storage rack. T ae count rate vill also be -
monitored whenever spent fuel is being loaded into a rack unless fresh fuel of the same initial enrichment has been pre-viously stored in the rack ar,1 an adequate suberitical margin has been verified."
We believe that adherence to these rer irements vill provide added assurance that criticality is not inadvertently.tttained during loading of fuel into the storage rack.
Condition 3 of Maintenance Instruction 506Eh presently requires that two of the charging pumps be in a reacy standby condition for addition of concentrated boric acid to the pre *:sure vessel whenever the reactor vessel head is removed.
Yankee has proposed that this Condition be changed to require only that two charging purrps be in a ready standby condition for addition of boric acid to the pressur e vessel during movement of fuel.
j We have reviewed the proposal a; d find that the two pumps should be available to add boric acid at any t me during refueling when there is a change in core geometry which could :redibly result in the reactor going critical. This could include movement of control rods.
Yankee agreed 4
to this general provision. They rer,uested, however, that the requirement i
not ce applied to the replacement o ? control rods at the end of Core II life.
Failure of Core II control rod cladding may result in excessive quantities of radioactive silver ir the reactor vessel and shield tank cavity water. Accordingly, Yankea wishes to keep a purifica. on system in operation during control rod replacement.
Operation of the purification
- o.
system requires that two of the three charging pumps be connected to it.
Only one pu=p would then remain available for boron injection into the core.
ln -vhv of the above, Yankee has re quested that Condition 3 of " sin-tenince Instruction 506Eh be revised to read:
"3.
During any change in core geometry, except during replacement of the Ag-In-Cd control rods at the end of Core II life, two of the char 61ng pumps are in ready standby condition for
~
addition of concentrated boric acid to the pressure vessel.
During the replacement of the Ag-In-Cd rods at the end of Core II life, at least one charging pump shall be in a ready standby condition for addition of concentrated boric acid to the pressure vessel."
Yankee has reported that the core vill be shut dovn by at least a reactivity-margin of approximately -25 during the control rod replacement program to be performed at the end of Core II life. This should be an a=ple margin to insure against inadvertent criticality during contrcl rod replacement.
Accordingly, we believe that the requirements stated above for Condition 3 h-of Maintenance Instruction 506Eh are adequate from a safety standpoint.
Conclusion It is our opinion that Condition 5 of Maintenance Instruction 506E2 and Condition 3 of Mainter.ance Instruction 506Eh should be revised as stated above. Subject to these exceptions, we have concluded that Proposed Change No. 39 does not present significant hazards considerations not describe or implicit in the hazards summary report, and that there is reasonable assurance that the henRn and safety of the public vill net be endangered.
'Oripna! S! ped tj; khrt li Erjan Dobe rt H. Bryan, P '
Date : Am st 30, 1963 Research J Power Reactor Safety Branch Division of Licensing & Regulation L