ML20207P999
| ML20207P999 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/12/1987 |
| From: | Mcnutt G, Nesbitt P, Russell J TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20207P998 | List: |
| References | |
| 229.8-(B), 229.8-(B)-R01, 229.8-(B)-R1, NUDOCS 8701210037 | |
| Download: ML20207P999 (11) | |
Text
r TVA EMPLOYEE CONCERNS-REPORT NUMBER: 229.8(B)
SPECIAL PROGRAM
('
REPORT TYPE:
SEQUOYAH ELEMENT REVISION NUMBER:
1 TITLE:
INSTRUMENTATION AND CONTROL DESIGN Chilled Water. System, Level Switches PAGE 1 0F 10 REASON FOR REVISION:
1.
To incorporate comments from the field.
PREPARATION PREPARED BY:
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CONCURRENCES,
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C SIGNATURE DATE SIGNATURE
- DATE APPROVED BY:
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NIA ECSP MANAGER DATE MANAGER OF NUCLEAR POWER DATE CONCURRENCE (FINAL REPORT ONLY)
- SRP Secretary's signature denotes SRP concurrences are in files.
G701210037 870113 PDR ADOCK 05000327
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M TVA EMPLOYEE. CONCERNS REPORT NUMBER: _229.8.(B)-
~ SPECIAL: PROGRAM e
~ REVISION NUMBER: 1:
[
PAGE 2.0F.10 t.-
- 1.
CHARACTERIZATION OF-ISSUES:
-Concern:-
Issue:
- IN-85-772-006 Level control switches for chilled There.is one flow switch water system expansion tanks do not
- (Mercoid?) :that indicates tank provide for a suitable means for water level and-adds water to automaticirefilling of'the tanks.
tank.- Operations has to work the ' switch manually to fill the tank. - This is inefficient.. - One
~ switch'is ~needed for high water
-level, and one for: low water level. Examples: Control Room,_A5 & R line, Elev. 373,
. system 31. - Switch 0-LS-031-17.
A & B board = rooms, Dwg 47W865-8 Rev 7, 737 Elev, LS-177:& LS-147.
Electrical board room, Dwg 47W865-7.Rev 6, 692 El.
0-LS-31-226, 0-LS-31-223, 0-LS-31-256,- 0-LS-31-253, Incore instrumentiroom dwg 47W865-5 Rev 4, control room annunciators, LS-031-303, LS-031-324.
CI has no additional information.
Nuclear Po_ wer concern.
2.
HAVE ISSUES BEEN IDENTIFIED IN ANOTHER SYSTEMATIC ANALYSIS? -YES NO X
-Identified by Not Applicable Date Not Applicable Documentation Identifiers:
Not Applicable 3;
- DOCUMENT NOS., TAG NOS., LOCATIONS OR OTHER SPECIFIC DESCRIPTIVE
-IDENTIFICATIONS STATED IN ELEMENT:
The instrument tag numbers listed in the concern are typical for WBN.
The instruments at SQN performing the equivalent function are the following:
y 0514D - 12/19/86
n
'TVA EMPLOYEE CONCERNS REPORT' NUMBER: 229.8(B)
~
.SPECIAL PROGRAM REVISION NUMBER: L1 f
PAGE 3 0F 10 Instrument-Description LS-305.
Shutdown Board Rooms Chilled Water System, Compression Tank A-A.*
LS-340 Shutdown Board Rooms Chilled Water System, Compression Tank B-B.*
LS-626 Auxiliary Building General Ventilation, Chilled Water System Expansion Tank
- Level switch in safety-related chilled water loop.
4 INTERVIEW FILES ~ REVIEWED:
IN-85-772 expurgated file and working file containing the following were reviewed on October 15, 1986:
Exp. File:
1.
K-Forms 001 thru 009 2.
Form OY350, File Screening Sheet, QTC Employee
-Concern File Working File:
1.
K-Form 001 2.
Form M.1, Att.G 3.
Memo, 9/19/85, W. H. Thompson to E. R. Ennis with Attached: WBN P&E (Nuclear) Employee Concern Report 4..
Memo 12/?3/85,-W. T. Cottle to W. H. Thompson 5.
W. H. Thompson to E. R. Ennis memo,1/3/85, stating that item 3) report doesn't answer concern and should be performed by nonline management.
5.
DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
See Appendix A.
6.
WHAT REGULATIONS, LICENSING COMMITMENTS, DESIGN REQUIREMENTS OR OTHER APPLY OR CONTROL IN THIS AREA?
See Appendix A.
7.
LIST REQUESTS FOR INFORMATION, MEETINGS, TELEPHONE CALLS, AND C'HER
( '
DISCUSSIONS RELATED TO ELEMENT.
~~~
See Appendix A.
0514D - 12/19/86
,I e
TVA EMPLOYEE CONCERNS-REPORT NUMBER: 229.8 (B)'
e SPECIAL PROGRAM REVISION NUMBER:
1 PAGE 4 0F_10 8.-
EVALUATION PROCESS:
a
~ Reviewed EC IN-85-772-006 to determine applicability to Sequoyah.
b.-
Reviewed the chilled water systems design for_the Main Control Room, A & B board rooms, electrical board room, and incore' instrument room to establish requirement for automatic refill of compression tanks.
Reviewed suitability for automatic function of existing level c..
switches.
9.
DISCUSSION, FINDINGS, AND CONCLUSIONS:
Discussion:
Background
Concern IN-85-772-006 addresses the demineralized water makeup to the chilled water loop supporting several air-conditioning _
systems.
The concern centers on the adequacy of the makeup methods as designed and does not contend that the present methods are unworkable or unsafe. Therefore, while the concern does include two chilled water loops that are a safety-related, the issue does not present a safety-related problem.
The concern was initially raised 08/22/85 on WBN. Since the SQN chilled water loop design employs similar demineralized water _
i makeup techniques, the concern is considered generic to SQN.
The issue was investigated at WBN without resolution (App. A, Sa).
This concern is being' investigated for SQN on that basis.
System Description
The air-conditioning systems in question each employ a closed chilled water loop to convey heat from air handling units to refrigeration chillers. A compression tank, also referred to as an expansion tank,-is connected to the chilled water pump suction.
The purpose of this tank is to accommodate the loop swell and shrinkage resulting from temperature variations and to ensure positive pump suction.
The tank is not intended for inventory l
storage. A low level switch installed below the tank senses the 05140 - 12/19/86
,e
=
,n.
TVA-EMPLOYEE CONCERNS REPORT NUMB 5R: 229.8(B).
SPECIAL PROGRAM REVISION NUMBER:. 1 PAGE 5 0F 10 need for makeup and energizes a solenoid-operated valve allowing
.the' admission of demineralized water to the system under regulated pressure conditions. As the level rises, the switch resets and demineralized water admission is cut off. The system is designed for automatic operation without manual control for operator override.
Analysis The operative portion of the concern states that:
" Operations has to work the switch manually to fill the t ank.'
This is inefficient. One switch.is needed for high water level, and one for low water level."
The documents reviewed show that the compression tanks have a Mercoid Model No. 203G-7810 float type level switches with single pole double throw (SPDT) snap action contacts for low level actuation of automatic makeup. When the level rises past the
'l switch reset point, the solenoid-operated water admission valve closes. This means that only enough inventory is admitted to overcome the level switch set / reset hysteresis. The type of level switches used for this application have a narrow operating band, allowing a 1-1/4-inch differential between the set and reset levels.
Apparently the CI wants to widen the hysteresis band using a low level switch to energize the admission. valve and a high level switch to turn it off.
If the. compression tanks were open such an arrangement would probably work.
In closed tank, however, the possibility exists that the system could become over-pressurized.
If the tanks were filled to a level higher than switch reset level during low temperature conditions, there may not be sufficient expansion volume to accommodate swell as temperatures rise. This could result in excessive system operating pressures. Although the relief valves on the tank prevent unsafe pressurization, it is not i good practice to depend on relief valves for safe operation.
I Since the purpose of the tanks is not inventory storage, but to accommodate the loop swell and shrinkage resulting from temperature variations, large quantities of demineralized water are not required for system makeup.
4
'05140 - 12/19/86 b
TVA EMPLOYEE CONCERNS REPORT NUMBER: 22918-(B)
SPECIAL. PROGRAM.
REVISION NUMBER:
1-
~(~
PAGE 6 0F 10 Findings:
It is evident from the ccncern and from the documents reviewed that WBN and SQN use different methods for the chilled water system makeup. Where as SQN successfully employs automatic operation A~
without the requirement for manual control, WBN appears to have only. manual makeup control available.. Undocumented. field changes might have been implemented at WBN, but were nottevident at,5QN.
/
The present method of providing automatic makeup to the chilled _
'~
water system suitably considers the relevant design and operating parameters, and is an acceptable design.
Operational difficulties ~or excessive maintenance history for the compression tanks filling arrangement have not'been documented at SQN.
==
Conclusion:==
The chilled water makeup system as designed and operating' at SQN
-does not present any maintenance or operational difficulties.'
s The design change suggested in the concerni in and of itself, is j
-technically unsound.
The concern is not valid for SQN.
10.
CORRECTIVE ACTION:.
No corrective action is required.
0514D - 12/19/86
TVA EMPLOYEE CONCERNS REPORT NUMBER: 229.8 (B) 1 SPECIAL PROGRAM REVISION NUMBER:
1 f
1
'~
PAGE 7 0F 10 iAPPENDIX A' 5.
DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
TVA memo from Cottle to Thcmpso'n, " Response to Request for a.-
Investigation," (12/23/85)
^'
b.
TVA memo from Thompson to Ennis, " Request for Further Response'," (01/03/86) c.
SQN FSAR Section 9.4, " Heating, Ventilating and Air-conditioning" g
\\
d.
TVA Design Criteria SQN-DC-V-13.9.6, " Control: Building e,
Environmental Control System, System 31-CB"
/
TVA Mechanic'al Design Guide DG-M13.2.6 "Heatihn, Ventilhting, I
a s
e.
and Air-conditioning - General Design Requirenients for
',y Environmental Control Systems fcr Nuclear Safety-Related Buildings" u
t-s s,
f f.
TVA Design C; iteria SQN-DC" -V-13.9.3, " Auxiliary Guilding Ventilation.and Cooling, System 30/31AB'.'
5 g.
Carrier Air-conditionina Company _- System Design Manual,-
4 T
Part 3 - Piping Design i,
~
b.
Mercoid Catalog, Series 201 - Side Mounted Level Switches y
i.
SQN TVA. Drawing 47W611,-31 Control Building Units 1 & 2 j
Mechani:al Logic Diagram
'{
~
j.
SQN TVA Drawing 47W611-31 Auxiliary Building Units 1 & 2 Mechanical Logic Diagra, Air-conditioning System k.
SQN TVA Drawing 47W611-31 Auxiliary Building Units 1 & 2
/
4 Mechanical Logic Diagram Air-conditiening System i
>i
's, 1.
SQN TVA Drawing 47W611431 Auxiliary Building' Units 1 & 2j S "
Mechanical Logic Diagram Air-conditioning System
,\\4 8
/
m.
SQN TVA Drawing 47W611-31 Auxiliary Building Units 1 & 2 Mechanical Logic Diagram Air-conditioning System n.
SQN TVA Drawing 47W920 Powerhouse Auxiliary Building Mechanical Heating Ventilating and Air-conditioning
{i 6
l 4
j 05140 - 12/19/86 bi.
c-TVA EMPLOYEE CONCERNS REPORT NUMBER: 229.8 (B)
SPECIAL PROGRAM REVISION NUMBER:
1~
j PAGE 8 0F 10 i
APPENDIX A (cont'd)
SQN TVA Drawing 47W865 Powerhouse Control Building Flow o.
Diagram - Air-conditioning Refrigerant Flow p.
SQN TVA Drawing 47W865 Powerhouse Control Building. Flow Diagram - Air-conditioning Refrigerant Flow -
q.
SQN TVA Drawing 47WS65 Auxiliary Building Units 1 & 2 Flow Diagram - Air-conditioning Chilled Water SQN TVA Drawing 47W865 Powerhouse Auxiliary Building Flow r.
Diagram General Ventilation Chilled Water-s s.
SQN TVA Drawing 47W866 Powerhouse Auxiliary Building Flow Diagram Heating Ventilating & Air-conditioning Air Flow t.
SQN TVA Drawing 47W866 Fowerhouse Auxiliary Building Flow Diagram Heating Ventilating & Air-conditioning Air Flow u.
SQN TVA Drawing 47W611-30 Auxiliary Building Units 1 & 2 Mechanical Logic Diagram Ventilation System v.
SQN TVA Drawing 47W867 Powerhouse Control Building Mechanical Air-conditioning Control Diagram SQN TVA Drawing 47W867 Powerhouse Control Building w.
Mechanical Air-conditioning Control Diagram x.
SQN TVA Drawing 47W867 Powerhouse Control Building Mechanical Air-conditioning Control Diagram y..
SQN TVA Drawing 47W867 Powerhouse Control Building Mechanical Heating Ventilating & Air-conditioning Controls SQN TVA Drawing 47W867 Auxiliary Building Units 1 & 2 z.
Mechanical Air-conditioning Control Diagram i
SQN TVA Drawing 47W867 Powerhouse Auxiliary Building aa.
Mechanical Heating, Ventilating and Air-conditioning Controls bb.
SQN TVA Drawing 47W867 Auxiliary Building Units 1 & 2 Mechanical Air-conditioning Control Diagram cc.
SQN TVA Drawing 47W922 Powerhouse Auxiliary Building Mechanical Heating, Ventilating and Air-conditioning Control dd.
SQN TVA Drawing 47W922 Powerhouse Auxiliary Building l
Mechanical Heating, Ventilating and Air-conditioning Control E
_05140 - 12/19/86
.eg TVA EMPLOYEE CONCERNS REPORT NUMBER: 229.8(B)
SPECIAL PROGRAM REVISION NUMBER:
1
.c PAGE 9 0F 10 APPENDIX A (cont'd) ee.
SQN TVA Drawing 47W922 Powerhouse Auxiliary Building Mechanical Heating, Ventilating and Air-conditioning Control ff.
SQN TVA Drawing 47W922 Powerhouse Auxiliary Building Mechanical Heating, Ventilating and Air-conditioning Control gg.
SQN TVA Drawing 47W922 Powerhouse Auxiliary Building Mechanical Heating, Ventilating and Air-conditioning. Control hh.
SQN TVA Drawing 47W922 Powerhouse Auxiliary Building Mechanical Heating, Ventilating and Air-conditioning Control ii.
47B865-31C Powerhouse Units 1 & 2 Mechanical Instrument Tabulation jj.
478865-31C Powerhouse Units 1 & 2 Mechanical Instrument Tabulation kk.
478865-31C Powerhouse Units 1 & 2 Mechanical Inst.ument Tabulation 11.
478865-31C Auxiliary Building Mechanical Instrument Tabulation mm.
47B865-31C Auxiliary Building Mechanical Instrument
-Tabulation nn.
47B865-31C Auxiliary Building Mechanical Instrument Tabulation oo.
47B865-31C Auxiliary Building Mechanical Instrument Tabulation pp.
478865-31C Auxiliary Building Mechanical Instrument Tabulation qq.
Memo from E. Croft to L. Damon, " Shutdown Board Room Compression Tank Control," (11/25/86) 6.
WHAT REGULATIONS, LICENSING COMMITMENTS, DESIGN REQUIREMENTS OR OTHER APPLY OR CONTROL IN THIS AREA?
None t
0514D - 12/19/86
TVA-EMPLOYEE CONCERNS REPORT NUMBER: 229.8(B)~
SPECIAL PROGRAM REVISION NUMBER:
1
~(J PAGE 10 0F 10 APPENDIX A (cont'd)'
7.
LIST REQUESTS FOR INFORMATION, MEETINGS, TELEPHONE CALLS, AND OTHER DISCUSSIONS RELATED TO ELEMENT.
Telephone call' P. Nesbitt, TVA, To L. Damon, Bechtel, a.
(09/29/86) b.
Telephone call G. Andrejeff, Bechtel, to D. Knudsen, Bechtel, (11/14/86) d.
Telephone call G. Andrejeff, Bechtel, to D. Knudsen, Bechtel, (12/17/86) l{'
4 l
t 05140 - 12/19/86
. (> '
'PAGE 265'.
REFERENCE
- ECFS120J-ECPS121C TENNESSEE VALLEY AUTHORITY-'
RUN TIME - 12:49: 31 e r OFFICE OF HUCLEAR P0HER
'RUN DATE -.12/02/86 a FREQUENCY
- REQUEST EMPLOYEE CONCERN PROGRAM SYSTEM (ECPS).
J.*
() 'ONP - 1555 - RHM
-LIST OF EMPLOYEE CONCERN INFORMATION CATEGORY: EN. DES PROCESS & OUTPUT SUBCATEGORY: 22908 TANK LVL SHITCHES REQUIRE MANUAL FILLING OPERATION-KEYWORD A
' ()
S GENERIC KEYNORD B H
APPL.
QTC/NSRS P
CONCERN SUB R PLT _ BBSH INVESTIGATION.
S CONCERN.
KEYHORD C KEYHORD D NUMBER CAT CAT D LOC FLQB REPORT.
k.
DESCRIPTION
)
NO-THERE IS ONE FLOW SHITCH (MERCOID !)
DESIGN PROCESS IN 772-006 EN 22908 N HBN NNYY THAT INDICATES TANK HATER LEVEL AND SCHEDULE T50123 REPORT ADDS HATER TO TANK.
OPERATIONS HAS INSTRUMENTATION 4
TO HORK THE SHITCH MANUALLY TO FILL INSTRUMENT / MECH t
()
THE TANK. THIS IS INEFFICIENT. OH E SHITCH IS NEEDED FOR HIGH HATER LE--
-VEL, AND ONE FOR LOH HATER LEVEL. E XAMPLES: CONTROL ROOM, A5 & R LINE,
()
ELEV. 737, SYSTEM 31.
SHITCH 0-LS-0 2
31-71.
A & B BOARD ROOMS, DHG 47:186 5-8 REV 7, 737 ELEV, LS-117 & LS'.47.
ELECTRICAL BOARD ROOM, DHG 47Ht65
- '40
-7 REV 6, 692 EL, 0-LS-51-226 0-LS-j 31-223, 0-LS-31-256,.0-LS-31-253 C) 1 CONCERHS FOR CATEGORY EN SUBCATEGORY 22908
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A 7
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_ _ _ _ _ _. _ _ _ _ _ _ _. _ _ _ _. _ _ _ _. _ _ _ _,