ML20010E083
| ML20010E083 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 08/24/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Borgmann E CINCINNATI GAS & ELECTRIC CO. |
| References | |
| IEB-79-15, NUDOCS 8109030049 | |
| Download: ML20010E083 (3) | |
Text
I
-~
rn j'
y
' my g
f Dist.
- Docket File bcc:
LB#1 Rdg TERA DEisenhut NRC/PDR AUG 2 4 88I BJYoungblood L/PDR Docket No.:
50-358 MRushbrook NSIC IPeltier TIC
- Q(to
-)
RLTedesco 1
Mr. Earl A. Borgmann RVollmer 0
' /',A Vice President, Engineering TMurley (rf % %[J k' The Cincinnati Gas & Electric Cmpany RMattson P. O. Box 960 RHartfield, MPA (s
M 1 f3.2O N " ".@
Cincinnati, Ohio 45201 WJohnston OELD ig*".[9,
Dear Mr. Borgaann:
01E (3)
/
h/
Subj ect: Long Tem Operability of Daep Draft Punps M #.h
/ N IE Bulletin 79-15, dated July 11, 1979, was issued to all licensees and holders of construction permits as a result of deep draft punp deficiencies that were identified at facilities both operating and under construction.
In your response to the bulletin you identified deep draft pumps E being utilhed at your facility. However, your response to the bulletin did not include enough infornation to denonstrate and assure the long tem operability of these pumps.
Enclosed is a document entitled, " Guidelines for Demanstration of Operability of Deep Draft Punps." Within 60 days from the issuance datc of this letter, you should provide information on all the deep draft putapt, i%itified in your bulletin response and describe the extent to which your deep draf t punp long term operability assurance progran.confoms to the various portions of these Guidelines. Enphasis should be placed on (1) the establishment of installation procedures that are folloved each time these punps are disassembled and reinstalled, and (2) the testing requirenents and bearing wear criteria. The instrunentation called for in the Guidelines should not be considered a requirement.
These Guidelines establish an acceptable method of assuring inng term operability of deep draft ptnps.
They do not necessarily constitute the only method for demonstrating long tem operability. The staff will review the information you submit to detemine whether your long term operability assurance progra~i for deep draft pumps is in sufficient confomance with these Guidelines to assure long tem operability.
If not, the staff will 7-detemine whether you have established and utilized other nethods and 4
procedures, preferably with the assistance of the pulp manufacturer, that also deaonstrate and assure that these. punps will perform their intended function for the length of time required.
6 I
auasam) 8109030049 810824
" PDR ADOCK 05000350
' '.' ~ ~"~" ~
onn)
G PDR
,.........i...............i..................
- -.-.~..~.-
NRC FORM 318 tIO 80l NRCfA 0240 OFFICIAL RECORD COPY
- " 8
- 32 824
i 3,
n k)
's G
y l
. AUG 211991 1
If you have any questions regarding this matter, please contact the i
Licensing Project Manag?r.
Sinsarely, j
g.i.imed its p t &,. Tsusce 4
Robert L. Tedesco, Assistant Director for Licensing Division of Licensing Office of Nuclear Reactor Regulation
Enclosure:
Guidelines for Denonstration of Operability of Deep Draft Punps cc w/ enclosure:
See next page 4
i 1
4 l
1
]
$ h.
t; v
i
"'c'>.DL:LB#
'. DL
. DL:AD 1
IPel'ile ys ngblood RLTe 'sco suamaur)
'87ff78T"""
'8' 8T"""" ST'jy81"" "
' " ' " " " " ~ "
,,,, p j unc ronu ais sio so> nucu o24o OFFICIAL RECORD COPY W M N-329 824
Mr. Earl A. Borgmann 7
Senior Vice President Cincinnati Gas & Electric Company Post Office Box 960 Cincinnati, Ohio 45201 cc: Troy B. Conner, Jr., Esq.
Mrs. liary Reder Conner, Moore & Corber Box 270, Rt. 2 1747 Pennsylvania Avenue, N.W.
California, Kentucky 41007 Washington, D. C.
20006 Andrew B. Dennison, Esq.
Mr. William J. Moran 200 Main Street General Counsel Batavia, Ohio 45103 Cincinnati Gas & Electric Cunpany Post Office Box 960 George E. Pattison, Esq.
Cincinnati, Ohio 45201 Clermont County Proscuting Attorney 462 Main Street Mr. Samuel H. Porter Batavia, Ohio 45103 Porter, Wright, Morris & Arthur 37 West Broad Street Resident inspector /Zimmer Columbus, Ohio 43215 RFD 1, Post Office Box 2021 U. S. Route 52 Mr. James D. Flynn, Manager Moscow, Ohio 45153 Licensing Environmental Affairs Cincinnati Gas & Electric Company Mr. John Youkilis Post Office Box 960 Office of the Honor & Die William Gradison Cincinnati, Ohio 45201 United States House of Representatives Washington, D. C.
20515 David Martin, Esc.
Office of the Attorney General Timothy S. Hogan, Jr., Chairman 209 St. Clair Street Board of Commissioners First Floor 50 Market Street, ;larmont County Frankfort, Kentucky 40601 Batavia, Ohio 45103 James H. Feldman,Jr., Esq.
Lawrence R. Fissc. Esq.
216 East 9th Street Assistant Prosecuting Attorney Cincinnati, Ohio 45220 462 Main Street W. Peter Heile, Esq.
Assistant City Solicitor l
Room 214, City Hali Cincinnati, Ohio 45220 l
John D. Woliver, Esq.
Legal Aid Security Post Office Box #47 550 Kilgore Street Batavia, Ohio 45103 i
l
m ENCLOSURE GUIDELINES FOR DEMONSTRATION OF OPERASILITY OF DEEP DRAFT PUMPS DISCUSSION 1.E.Bulletin 79-15 dated July 1979, identified problems associated with deep-draf t pumps found at operating f acilities and near term operr. ting licensee facilities.
Deep draf t pumps,dich are also called " vertical turbine pumps are usually 30 to 60 feet in length with impellers located in casing bowls at the icwest elevation of the pump.
The motor (driver) is located at the highest pump elevttion with the discharge nozzle just below the motor.
Bulletin 79-15 was initiated because several nuclear power plant facilities could not demonstrate operability of their pumps. The
~
pumps were experiencing excessive vibration and bearing wear.
The'~ -
rapid bearing wear sugges'-4 that these pumps could not perform their required function.
.1ng or following an accident.
As a result of the staff's initial review of the responses to IEB 79-15,.
several plants were identif'ted as having potential problems with their deep draf t pumps.
These guidelines are provided for these '
plants so that the licensee or applicant involved may have a method acceptable to the staff for demonstrating the operability of deep-draft pumps.
9 e
SW 8L@69#2c4 L83 j
v GUIDELINES FOR DEMONSTRATION OF OPERABILITY OF DEEP DRAFT PUMPS DISCUSSION 1.E.Bulletin 79-15 dated July 1979, identified problems associated with deep-draf t pumps found at operating facilities and near tenn operating licensee facilities.
Deep draft pumps,which are also called " vertical turbine pumps; are usually 30 to 60 feet in length with impe11ers located in casing bowls at the loiest clevation of the pump.
The motor (driver) is located at the highest pump elevation with the discharge nozzle just below the mntor.
c Bulletin 79-15 was initiated because several nuclear power plant facilities could not demonstrate operability of their pumps.
The
~
pumps were experiencing excessive vibration and bearing wes.
The'~
~
rapid bearing wear su5gested that these pumps could not perform their required functions during or following an accident.
As a result of the staff's initial review of the responses to IEB 79-15,.
several plants were identif'ied as having potential problems with their deep draft pumps.
These guidd ines are provided for these '
plants so that the licensee or applicant involved may have a method acceptable to the staff for demonstrating the operability of deep-draft pumps.
~
e
(
<2-DEEP DRAFT PUMP JPERATING CHARACTERISTICS In order to better understand the operating characteristics of 1
these purps, a rotor (ynamics analyses was performed to ascertain the response of the pump rotor under steady state operation.
The analyses cor.sidered journal bearing to shaft dynamic response at various eccentricities and fluid viscosities. The model for the analysis depicted a typical deep draf t purp utilized by. the nuclear industry. The analysis resulted in recommendation,s for improving the stability of the pump rotor from externally applied inputs and by self-generated inputs.
The conclusions which were derived from the analysis and staff evaluations of North Anna, Beaver Valley and Surry faciltties witn similar purgs include:
1.) Pumps with this type of configuration are prone to bearing whirl vibration problets due to the flexibility of the rotor and casing structure.
This phennmenon is accentuated as journal bearing clearance becotes large.
This phenomenon l
1eads to bearing wear (Journal bearings).
1 4
1
" Low Head Safety Injection Pucp Rotor Dynamic Analyses", by Franklin Research Center, Report FC4982, dateo May 1980.
t l
i
. 2.) There may be natural frequencies associated with the pump assembly which occur near the operating speed of the pump.
pump operation will drive these frequencies and can cause bearing wear.
The severity of this condition is dependent on bearing diametral clearance, rotor unbalance conditions and housing flexibility.
As an example, if the wear in column journal bearings becomes sufficiently large (twice the original diametral clearance)~se that
~
these bearings are no longer active and the undamped critical frequency near the operating speed of the pump is allowed to expand, the additional uncontrolled bearing wear will occur. This wear can continue until the shaft rubs against the support structure of the bearing and can potentially sever the shaft.
3.) One acceptable method for correcting instabilities in the pump shaft is to utilize a journal bearing design which exhibits stable characteristics.
One such design is the
' Taper land bearing". This design is more stable thare the plain journal bearing, is less susceptible to wear because of the taper and will cause the bearing to form a hydro-dynaute film quickly during startup.
P e
e
-e
_4_
4.) Stiffening of the column sections of the pu=p is advantageous if there is a column frequency near the operating speed of the pump.
The shif ting of the column frequency to a higher icvel will eliminate any coupling between the pump operating speed and the column frequency.
5.) Flow inlet conditions to the pumps and su p derigns can be important so pump operability.
Certain installations have demonstrated flow characteristics which produced vortexing at the be11 mouth of the pump. This vortexing is due to sump design or sump supply line e1 trance con-
' ' ~
di tions.
This condition can centribute to additional pump vibration and wear.
Flow straightener devices, j
reduction of be11 mouth diameters, and bottom clearance reductions have proven to be effective in eliminating this problem.
C.) This type of pump has exhibited operational proble.-i due to design and installation deficiencies.
The high flexibility of the shaf t and column make this design rather forgiving when it comes to installation deficien-cies such as misalignment between the shaft and column,
.O w
low-precision coupling assemblies, and non-perpendicular mounting flanges. This fact however, can lead to excessive bearir.g wear without significant noticeable change in pump operatin'g characteristics. To ensure proper pump operation, 9
proper alignment should be established between all mating surfaces and measures should be emphasized which prev'ent column ar.d shaft eccentricities. These measures can include optical alignment of the column segments, use of high precision couplings and use of accurate techniques to establish that the sump plumb line is perpendicular to the pump mounting fl anne.
The above findings and conclusions have contributed significantly to the development of these guidelines. The guidelines listed below are divided inia installation and test areas.
The subjects to be addressed in these areas are considered to be of prime importance when establishing a pump operability assurance program.
The extent to which each of the two areas are implemented at a specific facility is dependent on specific symptoms which have c
s been identified with these pumps while in operation and' during service periods.
e
- e
, Implementing the measures outlined below, at North Anna 1 & 2 in total has been shown to provide reasonable assurance that the pumps will be operable when required for their safety function. These guidelines are not intended to replace the requirements of Standard Review Plan 3.9.3, Regulatory Gaide 1.68 or any other requirements ' presently enforced by the staff.
Rather, the guidelines are to be used as supplementary material for establishing deep-draft pump operability.
GUIDELINES FOR OPERABILITY INSTALLATION 1.0 INSTALLATION PROCEDURES 4
Experience has shown that these pumps are prone to having operability problems as a result of poor installation proced,ures.
The guidelines emphasize those areas of the installation procedure, wnich if implemented, could significantly improve the likelihood of an operable pump.
The procedures utilized should be submitted to the staff for review.
t 1.1 PUFP INSTALLATION Determine by measurement that all shaft segments are straight a.
within tolerances specified by the m;.nufacturer.
b.
Determine by measurement or provide certification that all couplings (for shaf t segments & ' pump to notor coupling) are of high precision as specified by the manufacturer.
Determine by measurement that all pump segment flanges are c.
perpendicular to the centerline of the segment, that the segments are straight and that any mating surf aces are l
i concentric to an established datum.
k'here journal
7-
, bearing guides (SPIDERS) are used, establish con-centricity between this assembly and its r:uting surf ace.
d.
Align full pump casing assembly optically to assure maxicum straightness and concentricity of the asse..bly.
~
l Any equivalent rnethod is acceptable, as long as the procedure stresses column straightness and concentricity.
Assure pump to motor flange perpendicularity and that e.
proper coupling installation is perforned.
f.
Assure that all mating surface bolting is properly attached and that tranuf acturer torquing sequences are adhered to.
1.2 SUMP INSTALLATION Assure (where used) that sump / pump mating flange a.
l is perpendicular to the sump pump line.
~
b.
Assure that sump design prevents fluid anomalies such as vortexing or turbulence near the intake to the pump be11 mouth and that incoming piping is not so designed as to allow fluid conditions 1
f avorab'le to these anomalies (i.e., sharp
~
bends in piping prior to entrance. into sump).
c.
Assure that interference does 'not exist between I
the sump and arty pump appendage such as a seismic
~
restraint.
e
..,m.
e 8-2.0 Testing Recuirements The installation procedures are essential in establishing purp operability.
In addition to careful installation, testing cey be required which will verify proper operation of these pumps.
After cocpletion of the installation checks, licensees or appli-cants should evaluate the need for further testing and report the results of this evaluation together with the details of any test plans to the staff.
Should tests be required, an acceptable test procedure should include the items listed.helow.
The staff recognizes that the instrumentation and procedures outlined below may be difficult to implement at all fr-ilities and, therefore, the staff is erphasizing good installation practices which lead to operable components.
If tests demonstrating operability cannot entonpass all the iterrs listed below, then alternative procedures i
should be proposed for evaluation by the staff.
The tests should emphasize reasurement of pucp dynamic characteristics and wear data at different stages of testing, culminating with an cxtrapolation of the data to the desired life goal for the pump.
2.1 Test Instrumentation l
The following instrumentation should be incorporated into the l
test procedure aside f rom normal flow measurement, pressure and vibration instrumentation:
e e
G r
l
.g.
a.- ) X, Y proximity probes at three axial locatforis on the pump column, for measuring and recording radial positions of shaf t with respect to the column.
b.)
X, Y, accelerometers (at proximity probe locations) for measuring and recording radial accelerations of the column.
c.) Dynamic pressure transducers for measuring fluid pressure at the following locations:
1.
Bottom of Column (suction) 2.
Mid-Column 3.
Top of Column.
d.) Shaf t Rotational speed and dynamic variation instrument.
2.2 PRE-TEST DATA
~~ ~
With the pump disassembled, measure all journal bearing 0.D.'s, bearing 1.D. 's and calculate bearing diametral clearances.
In addition with pumps fully assembled and using the proximity probes,
obtain the " clearance circle" at each of the three axial stations by rolling the shaf t section within the clearance volume of'its bearings and in this way, establish proper operation of the p, robes.
s.
=-
' 3.1 PliASE 1 Testing (6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> plus start-stop)
This phase of testing should be comprised of 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> of testing (' ceak-in) followed by start-stop testing. Test conditions should simulate as nearly as possible normal and accident conditions.
Parameters to be considered are flow, temperature, debris, and chemical composit, ion of fluid being pumped.
Static torque tests should be
~
performed before and after the test (i.e. measure nount of torque required to turn shaft by hand).
Data should be taken during the six hour test at 1/2 hnur intervals.
A total of 12 start-stop tests will be performed con-sisting of a start up from zero speed up to full-speed, 10-minute dwell at full-speed and a shutdown from full speed to zero speed, with recording of all instrumentation during full cycle of start-stop.
l l
Upon completion of Phase 1 testing,the following data should be obtained and recorded:
l 1.) Obtain the " clearance circles" using the three sets of 1
proximity probes.
~
2Tests at North Anna 1 & 2 and Manufacturers input indicates that 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> is an adequate time interval for bearing " break in" period.
. 2. ) Heasure and record the following dimensions for each bearing:
a.) Journal 0.D.
b.) Bearing 1.D.
- c. ) Bearing to Journal diametral clearance
- d. ) Establish Phase 1 test bearing wear.
THE ACCEPTANCE CRITERI A IS A5 FOLLOWS:
3 1.)
If wear is)> 5 mils for any bearing, wear is unacceptable and test -thould be terminated. ' ~ '
3 2.)
If wear is( 5 mils for all bearings
- a. ) Reassenble the pung
- b. )
Obtain " clearance circles"
- c. )
Reinstall pump in test loop. ~-
2.4 Phase 2 Test < 1 (40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br />)
Phase 2 testing is to be performed at full system pressure.
l and temperature and fluid conditions simulating those expected during accident and nornal operation.
Before start and at cocpletion of Phase 2 test,obtain reasurement of static torque.
Data should be recorded continuously during the start-up period, l
l s
3This acceptable wear value ray be modified based on manufacturers recomr.endation.
5
~m 6
- and during the shutdown period. Data should also be recorded at 1-hour time intervals during the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> test.
The following measurements should be made at the conpletion of Phase'2 of the test:
1.) Obtain the " clearance circles" using the three sets of proximity probes.
2.) Measure and ecord the following dimensions for 'each bearing:
a.) Journal 0.D.
b.) Bearing I.D.
- c. ) Bearing to Journal diacetral clearance.
d.) Establish accumulated bearing wear.
THE ACCEPTANCE CRITERIA IS AS FOLLOW 5:
1.)
If accunulated bearing wear on any bearing is 36 mils, wear is unacceptable and test should be t e rmi nated.
2.)
If accumulated wear on all bearings is(7 mils 5
for all bearings.
a.)
Reassenble pump
- b. )
Obtain " clearance circles"
- c. )
Reinstall pump in test loop.
/
e
- e
m.
e 5.) Phase 3 Testing (95 hours0.0011 days <br />0.0264 hours <br />1.570767e-4 weeks <br />3.61475e-5 months <br />)
Phase 3 testing is to be performed at full system pressure and temperature and fluid conditions simulating those expected during accident and normal operation. The same procedures should,be followed as in Phase 2 testing except that data may be taken with less frequency.
The same measurements should be taken at the completion of this phase as with the other phases with the following acceptance criteria:
1.)
If accumulated bearing wear is> 8 mils for any bearing 3 wear is unacceptable and test should be tenninated.
2.)
If accumulated wear is ( 8 mils for all bearings, a s
decision needs to be made to establish:
a.)
the need for additional testing or e
b.)
whether or not the bearing wear will be acceptably low.
The recc= mended decision process is outlined below.
Plot the values of accumulated wear versus time (H) for each bearing after Phase 2 and Phase 3 tests, namely.
Wear at H2 = 54 hour6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br /> Wear at H3 = 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> l
l k
a s,
14 -
Straight lines are then drawn through the plotted values of wear and extended to the right (See example Figure 1).
If the extension
' intercepts the maximum acceptable value of wear (8 mils) at a value H less than the life goal for this pump, additional testing should be perfo.rmed.
If the intercept of the line with wear of 8 mils exceeds the life goal for this pump, no additional testing is required and bearing wear is acceptable.
If additional testing is deemed necessary it should be done in a similar manner to that performed during Phase 3 with similar acceptance criteria and decision process.
It is t :pected that such additional testing will either show a stable pump operation with no iacrease in bearing wear or increased bearing wear with unacceptable results.
2.6 Evaluation of Puma Acceptability If bearing wear (af ter all testing phases) is acceptably low (as per decision process) and if vibration levels over the frequency spectrum of 3 cps to 5000 cps are acceptably low and show no unfcvorable trend of increasing magnitude during the testing, the pump may be judged acceptable for its intended use, s
O
,1 _
. _. e _.._
t_.
t
-... ~.9 t
_. _..i-
.1_.._...____,
p _ _.
4 t
- - -- n -- -- m_ 7
._ _ _ 3_... _.
h--- t - -
c.
.=.J l
4 i...q m l_..,... g.,.g..o- =., p yg; rs:,. p ry.-:p. r..,g
.....,. - - - ;tl
?- -
r,..
i 1,, g.
l I N..tW
\\'
2-I 2
., g
.,i
\\ s, i
I l
.-=.
- a..I
/
N',.
_4..
.nf i
1..
/
. 6. y s
a g
.4.,
o_..
- /,.. j
,yv si g% e
-c-
-- -,p
1_
d s_
m
-s w,
I Y
q
-s 4
d
.p
.i \\ h g_
a t
.y.
3 t._
E s
n 11,,
\\ l y.-
--v,--%
%,l
.g o i
o w
k.- - :
J~
1.
a
~O u
~ f y'C,.. si
._J
/.
ff
.s Q- ~
q.\\. ** -
_7 4
3::
- .rei
/
l.e_ _i_
j
{
Y-es y
d,wi l
M.. l!
p
.:. \\
I i
o!
e 4
S - i '; \\
M! 1\\';- Vl.
_n:;- \\
s l
Y:
_ __. _ _ _.-wl _.g
....$n...
J
,r_.
. %.., i..
,.A_
n u ) off., _ g.gl
_ t.3
.x a
.g w 9) en.
e l
l
.o.,
i g.
i____+
n
. m.\\ P s h
. t.., v -
s c __
-a s
,1 9
s
- i. -
s, m
+<x, m
.~
L t
v lo _ _ L._ -4_
_F)
___ - - I - _,. : - w~ _b6 I
t ni 4
.__._l_..
x.. ;(rry/ f. y::.
.._.. _,:.n.- (,
_,,...n..
p,..
.... y.7 a
_.D _y. h. >.
3-
.r, ' t l
..l l
l
+.
t :._.
C..
a
.. _... y.f,
.[
F l....
. M3._,l.O.
.,2
. a.1 l
l g
9 f
t
'l
- - l
'f_ 'K..
1
... ?.
.V l
N
... N
. 9._:
.w. i.
._h,.. ' m.
_w I.. _..
w t
e n
.. i p) o g
ks.
n_
~
3_,
m u
i s.
T i _ __.
p__~ _ _ + o __
i
.i._,q l...
1 l-
, g
. i m 1yg2.3 = 9/
P:
1...
{ : _i_g
.. r.. _ _-. _. _.. _ I
....I.
i
.o.
4 j
s
.-..__.g___., _. _..
_ _...,_.._.._q,.
i i
t i
N.9 j.
_.sp:.i.M. i. 1
- : ii j :..
- i j
l
% _l 1.
J l
l.'
_i-i.'.
m
.... i'_.:'i ?.. ~_._ _._
..t,s.c.i.
.'s'r,
.,y,.
,t.L, o,
A g!
f.
l YN
... Q]
s N,.,
y 6
4 i
s n..-
t n
e.
i
. r :-
.. i 3
i q
1 3
_..o l...
. i......._._p...
.. _. i. u.
.: l...~.
4 u. _ _ __<
_..i...:_2 ; _.,.. :..
i I
.. G, _._. !. ! : l.. u.
ts_
5.
l 3
4 c
---l i
.a.:
t 1 -
1.-
-j-y.rL --_; : =. l.
i :..
.g.:g..:, q p..> ntyP?pq n n Dpy
= Q ;.i-W.q. o
.. 1
..i..
i
-(.rf.w) c.
.m
.N
....~w
. ~
OD..
I-A,3,..
i
.r N.:.e
....'.l.
- s.-
i...
..i,
.. g g.:.s. [. p.:. !
.l....
..h
. 4 0.q
.[
...j...,..:..
.I y....
.,8,:
,