ML20214S732
| ML20214S732 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 11/26/1986 |
| From: | Sears P Office of Nuclear Reactor Regulation |
| To: | Randazza J Maine Yankee |
| References | |
| NUDOCS 8612080367 | |
| Download: ML20214S732 (4) | |
Text
_.
NOV 2 61986 DM 04 Docket No. 50-309 Mr. J. B. Randazza Executive Vice President Maine Yankee Atomic Power Company 83 Edison Drive Augusta, Maine 04336
Dear Mr. Randazza:
SUBJECT:
MAINE YANREE INADEQUATE CORE COOLING INSTRUMENTATION SYSTEM The staff, with its consultants at Oak Ridge National Laboratory, has completed its review of your submittal dated October 31, 1986 concerning the proposed revisions to the Inadequate Core Cooling Instrumentation System for the Maine Yankee Atomic Power Station. Additional information is needed so that the review may be completed. That information and pertinent coments are described in the enclosure. Please provide the requested information within 60 days of receipt of this letter.
The information requested in this letter affects fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely,
.origina1WD Patrick M. Sears, Project Manager PWR Project Directorate #8 Division of PWR Licensing-B
Enclosure:
Request for Additional Information cc w/ enclosure:
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Mr. J. B. Randazza Maine Yankee Atomic Power Company Maine Yankee Atomic Power Station cc:
Charles E. Monty, President Mr. P. L. Anderson, Project Manager Maine Yankee Atomic Power Company Yankee Atomic _ Electric Company 83 Edison Drive 1671 Worchester Road Augusta, Maine 04336 Framingham, Massachusetts 07101 Mr. Charles B. Brinkman Mr. G. D. Whittier
. Manager - Washington Nuclear Licensing Section Head Operations Maine Yankee Atomic Power Company Combustion Engineering, Inc.
83 Edison Drive 7910 Woodmont Avenue Augusta, Maine 04336 i
Bethesda, Maryland 20814 John A. Ritsher, Esquire Ropes & Gray 225 Franklin Street l
Boston, Massachusetts 02110 State Planning Officer Executive Department 189 State Street Augusta, Maine 04330 Mr. John H. Garrity, Plant Manager Maine Yankee Atomic Power Company 4
P. 0.-Box 408
..i Wiscasset, Maine 04578 6
Regional Admin'istrator, Region I U.S. Nuclear Regulatory Commission i
631 Park Avenue King of Prussia, Pennsylvania 19406 First Selectman of Wiscasset Municipal Building U.S. Route 1 1
l Wiscasset, Maine 04578 1
i Mr. Cornelius F. Holden l
Resident Inspector i
c/o U.S. Nuclear Regulatory Commission P. O. Box E Wiscasset, Maine 04578 4
__.c.,.
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4 REQUEST FOR ADDITIONAL INFORMATION MAINE YANKtt AIUMIC POWER 51ATIUM INADEQUATE CORE COOLING IN51RUMENTATION SYSTEM A.
SUBC00 LING MARGIN MONITOR (SM)
The revised proposal for the SMM as outlined in Maine Yankee's submittal of October 31, 1986 includes better separation of redundant l
channels, including separate pressure, core exit temperatures, and class IE power supplies for each channel. This new separation should satisfy the redundancy requirements of NUREG-0737, II.F.2. A new 4
interaction is introduced by the design between the SMM, CET and PITS indications. A selector switch is used to choose which of the 8 CETs in a channel is displayed on the digital indicator. This same selection also chooses the same CET for use in the SMM calculation and for temp-erature compensation in the PITS. level indication. As a result, stepping l
through the CET indications will simultaneously change the SMM and PITS
~
indications. This interaction may not be desirable or acceptable in all situations. The licensee should provide a thorough discussion of this interaction in the SMM calculation and in the PITS level indication caused by switching from one CET to another.
Specific concerns about the revised SMM are as follows.
1.
Is appropriate Class 1E separation provided for the redundant channels?
l 2.
Are all components of the SMM system qualified for appropriate degraded environments, including seismic?
i
(
3.
The text of Maine Yankee's submittal states that margin to saturation is displayed while the accompanying table shows the " Operating Range" as T-SAT, 0 - 750*F. Does the instrument display saturation i
temperature or temperature margin to saturation? If margin is displayed, what range is used? (Reg. Guide 1.97 specifies a range of200*Fsubcoolingto35*Fsuperheat). The range of 0 - 750*F is appropriate for saturation temperature, but not for margin.
4.
Can the SMM system display pressure margin as well as temperature margin?
5.
Is recording or trending of saturation margin provided?
6.
Are alarms provided for low. saturation margin?
l 7.
Describea)meansofcheckingsystemduringoperation;b)adequacyof service, test,andcalibrationprocedures;c)administrativecontrol l
of access to setpoints, calibrations, test points, and removal from service; and d) availability of and training with steam tables and alternative indicators for backup margin calculation.
-, _ - - - -, _. ___ _ _.... -.... - -. _ _. _. _. _, ~,... _
4
_ l B.
Maine Yankee's revised proposal includes two redundant channels of 8 J
CETs per channel, with 2 CETs per core quadrant per channel. The channels are to be fully qualified and separately powered from class IE power supplies. The improved separation and the change to the minimum i
acceptable number of CETs in the backup displays should now satisfy the NUREG-0737 requirements.
Interaction between the SMM, CET and PITS systems is noted above.
Specific concerns about the revised CET system are as follows.
1 1.
An earlier submittal (Maine Yankee letter [MN-83-83] of April 29, 1983)wasnotclearaboutappropriatealarmcapabilityonCET temperatures consistent with operator procedure requirements (NUREG-0737,II.F.2, Item 2e). Please describe.
l 2.
Earlier submittals preceded the Control Room Design Review with respect to types and locations of displays and alarms determined by human-factors analysis (II.F.2, Att. 1 Item 4a-d). Please describe the present types and locations of displays and alarms.
j 3.
One of the CET backup display requirements (II.F.2, Att. 1. Item 3) l 1s to read the 16 thermocouples in no more than six minutes. With the arrangement proposed in the revised submittal, the CET selected i
for display in a channel also provides the same signal to the sub-cooling margin and vessel level systems. As a result, the indication of SMM and vessel level will change as different CETs at somewhat i
different temperatures are selected. This interaction between the i
g three systems may not be desirable or acceptable in all circumstances.
Describe the justification and human-factors considerations for this design feature.
i 4.
Describe the integration of ICC information, including CET indications, 4
i, into emergency procedures and training.
C.
PRIMARY INVENTORY TRENDING SYSTEM (PI'TS)
In the submittal, the PITS design proposal has been revised to include separate,redundantchannelsofdifferential-pressure (dp) measurement i
of reactor vessel coolant level..The measurements.now include compensation i
for changes in coolant density-(temperature) and temperature changes at the dp reference legs. Separate strip-chart recorders.are provided on the main control board for level indication, and separate class IE power sources are used. The measurement range of each channel is from the top to the bottom of the reactor vessel. These changes should greatly improve the accuracy and reliability of the PITS system. The i
proposal should now satisfy the requirements of NUREG-0737, pending i
satisfactory results of analysis of the system accuracy. The potential i
for interaction between the systems is noted above in the SMM description.
)
This analysis of the system accuracy should be provided to the staff when j
available.
i i
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