ML17277A913
| ML17277A913 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 10/05/1983 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Mazur D WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| References | |
| TAC-56674, NUDOCS 8310170131 | |
| Download: ML17277A913 (13) | |
Text
OCT 5
]983 Docket No. 50-397 Mr. D. H. Mazur Managing Director Washington Public Power Supply System P. 0. Box 968 3000 George Mashington ltay Richland, Washington 99352 DISTRIBUTION:
Document Control NRC PDR L
EHylton RAuluck
- WPaton, OELD ACRS (16)
- ELJordan, DEJA:IE
Dear Mr. Mazur:
Subject:
Request for Additional Information - Contro'I System Failures As a result of our review of your submittal regarding Outstanding Issue ¹13, "Control System Failures", in your [[letter::GO2-83-573, Forwards Deficiency Repts Re Condition 240,loss of ESF Loads on Undervoltage Trip & Condition 258,RHR HX Installation|letter dated June 24, 1983]], we find that we need additional information.
The specific information is described in.
To maintain our licensing review schedule for the lNP-2, we wi'll need re-sponses to the enclosed request by October 28, 1983, If you cannot meet this date, please inform us within seven days after receipt of this letter of the date you plan to submit your responses so that we may review our schedule for any necessary changes.
Please contact Raj Auluck, Licensing Project Manager, ifyou desire any discussion or clarification of the enclosed request.
Sincerely,
Enclosure:
As stated
<dnaI s1gned by A. Schwencer, Chief Licensing Branch No.
2 Division of Licensing cc w/enclosure:
See next page 8310170131 831005 PDR ADQCK 05000397 A
PDR OFFICE/
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NRC FORM 318 110/801 NRCM 0240 OFFICIAL RECORD COPY
- U.S. GPO 1983~00 247
0
<.p T I, 1
WNP-2 Mr. D. Mazur Managing Director Washington Public Power Supply System P. 0.
Box 968 3000 George Washington Way Richland, Washington 99352 CC:
Nicholas Reynolds, Esquire Debevoise
& Liberman 1200 Seventeenth
- Street, N.
W-Washington, D. C.
20036 Mr. G. E. Doupe, Esquire Washington Public Power Supply System P.O.
Box 968 3000 George Washington Way
- Richland, Washington 99352 Nicholas Lewis, Chairman Energy Facility Site Evaluation Council Mail Stop PY-11 Olympia, Washington 98504 Roger Nelson, Licensing Manager Washington Public Power Supply System P.O.
Box 968
- Richland, Washington 99352 Mr. W. G. Conn, Sr.
N/M Group Supervisor Burns and Roe, Incorporated 601 Williams Boulevard
- Richland, Washington 99352 Mr. Richard Feil U.S.
NRC Resident Inspector WPPSS-2 NPS P.O.
Box 69
- Richland, Washington 99352 Dr. G. D. Bouchey, Manager Nuclear Safety 5 Regulatory Programs Washington Public Power Supply System P.O.
Box 968, MD 650
- Richland, Washington 99352
ENCLOSURE 1
MNP-2 REQUEST FOR
- ADDITIONAL INFORMATION CONCER ING OPEN ITEN. 013 (CONTROL SYSTENS FAILURES) 031.143 It appears that control room indicators were not included in the devices Listed in Appendix B.
Verify that as part of your review, it was determined that sufficient controL room indication exists to allow the operator(s) to determine the status of the plant whiLe going to cold shutdown foLLowing the Loss of each CLass 1E and non"Class 1E bus.
031.144 I It is indicated in Sections 2.9 and 2.10 that if an alter-nate shutdown path is required, then existing procedures should be modified or new procedures developed to provide the operator with the appropriate actions to be taken foLLowing a
bus Loss.
Verify that the modified and/or new procedures wi LL be in place prior to fuel Load.
031.:145! It i s necessary when a
bus Loss af fecting the norma L shutdown path occurs, that the controL room operator(s) be alerted to this fact.
Appendix A identifies some bus Losses requiring shutdown via an aLternate path for which the only indication of bus failure is the Loss of position indication Lamps for certain devi ces (power buses PP-1B-A and PP-7A" C a re two examples)
The staf f does not consider the Loss of position indication Lamps to be a positive indication of a power bus failure affecting the capability to achieve a
normaL reactor shutdown.
ALL buses relied on to achieve a normal shutdown
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should be alarmed in the control room.
Provide a
commitment to implement Loss of power alarms for alL buses whose failure adversely affects the capability to shutdown via normaL procedures that are not presently alarmed.
031 146, Veri fy that IE Circular No.
79 02 "Fai Lure of 120 Volt Vital AC Power Supplies" dated January 11, 1979 was re-reviewed to include both Class 1E and non-Class 1E power supply inverters as required for operating reactors via IE BuLLetin 79"27 "Loss of Non-CLass 1E Instrumentation and Control Power System Bus During Operation" dated November 30, 1979.
031.';14?
Regarding Appendi x A "Cold Shutdown Power Bus Analysis":
(a)
Why is it necessary to use HPCS (i.e., the division II 8 III alternate cooldown path) upon Loss of power bus NC-8B? It appears that the normal shutdown path (i.e.,
main steam, condenser, feedwater, etc.) is stiLL ava i lab le.
(b)
Breaker trip annunciation and/or 0/L (overload) trip annunciation is relied on to alert the operator(s) to a
Loss of power conditon for a
number of buses.
It is not clear that this annunciation would always be provided (i.e.,
Loss of bus power for other reasons would not result in annunciation)
~
Justify the adequacy of these alarms.
4
'f
(c)
Loss of power bus NC-7B requires use of an alternate Low pressure cooldown path foLlowing high pressure cooldown using the normaL shutdown path.
Note 4 states that since both paths are not required simultaneously, further analysis is not necessary.
Verify that for this and simi Lar cases (i.e.,
aLL references to note 4) adequate alarms and procedures exist to instruct the operator(s) of the need to use the alternate shutdown path.
031.'148 PostuLated damage to non-saf ety related (cont ro L) systems from high energy Line breaks (HELBs) was Limited to jet impingement and/or pipe whip.
This is not acceptable.
The effects of HELBs on controL systems should also include environmentaL effects such as humidity, pressure, tempera-ture, etc.
Provide the results of the analyses of HELBS in the vi cinity of non-safety related systems which include environmental effects on these systems.
Describe the meth-odology used to determine which non"safety related (controL) systems are postuLated to be affected by the environmentaL effects of a given HELB.
031 '149 Verify that for each HELB event and its consequential cont rot systems failures, that redundant safety related systems are available (i.e.
unaffected by the event) to mitigate the effects of the event.
The intent here is to assure that the consequences of the event can be mitigated given a single failure within the systems used to mitigate the event.
C (
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031;150 There is no techni cat basis for exc Luding events that are not capabLe of occurring at 100% power from the analysis.
AL L operating modes should be considered.
The analysis shouLd be revised accordingly.
031'.151 Under Item 3 of Section 2.1.3, verify that for ruptured process tubing, the worst case failures of associated instrumentation are assumed (e.g., for Level 8 trip signals, assuming these instrument channels are not environmentaLLy qualified, the Level 8 signal is assumed to occur or to not occur whichever is worse for the scenario being considered).
031-.152~ Could a
HELB resulting in Loss of feedwater heating (see Section 3.1.1) also affect feedwater and turbine"generator controls (i.e., are controls for these systems Located in any of the "environmentaL zones" where this HELB couLd occur?).
031:]53! Veri fy that no credit was taken in the analysis for non-safety related equipment
( e.g.,
feedwater pump trip on Leve l 8) to mitigate the effects of HELBs and consequentiaL controL systems failures.
031~.154; It is assumed in the analysis that the turbine bypass system functions following a turbine trip.
Why was a turbine trip without bypass not considered in Section 3.2?
031'5
For HELB events it is not necessary to remain above the minimum criticaL power ratio (NCPR) safety Limit.
- However, verification should be provided that the worst case event
combinations considered are bounded by a
smaLL fraction
(<10%) of 10 CFR Part 100 guidelines.
The worst case events may change as a result of the environmental consid-erations discussed in Item 6 above.
03] E]56'rovi de a
List of non-saf ety related (control) systems considerd in your review (i.e., those systems described in Section 1.2.1 as potentiaLLy affecting reactor
- pressure, water Level, critical power ratio, feedwater temperature, and/or the performance of safety"grade equipment).
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03'f,.'t 57:,, It a p p e a r s t h a t t h i s a n a Ly s i s o n Ly c o n s i d e r s t h e e ffe c t s of multiple controL systems failures due to the failure of instrument Lines (either broken or plugged) and the associated effects on aLL sensors connected to the Line.
Are there any individua l sensors (not sharing an instrument Line with other sensors) that provide inputs to two or more controL systems?
If so~
the failure of these sensors should be analyzed to determine if the effects are bounded by the analysis in Chapter 15 and if they result in an event that requires action or response beyond the capability of the operators or safety systems.
031-.]58~ Veri fy that for at L sensor fai Lures (inc Luding multiple fai Lures due to instr ument Line fai Lures) resulting in
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controL systems malfunctions requiring protective actions, redundant safety related systems are avaiLable (i.e.,
unaffected by the failures) to mitigate the effects of the event.
The intent here is to assure that the effects of the event can be mitigated given a single failure within the systems used to mitigate the event.
031.159 C la rify the sentence "There were no sing Le ef fects that mitigate the totaL failure consequences."
in Section 3.4 (Analyze Combined Effects) of the analysis.