ML20203D426
| ML20203D426 | |
| Person / Time | |
|---|---|
| Issue date: | 04/18/1986 |
| From: | Merschoff E, Trottier E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| Shared Package | |
| ML20203D397 | List: |
| References | |
| REF-QA-99900373 NUDOCS 8604220106 | |
| Download: ML20203D426 (10) | |
Text
-
. l l
l ORGANIZATION: COOPER ENERGY SERVICES MOUNT VERNON, OHIO REPORT INSPECTION INSPECTION N0.- 99900373/85-01 DATE: 10/21-23/85 DN-SITE HOURS: 36 CORRESPONDENCE ' ADDRESS: Cooper Energy Services En-Tronic Controls Division ATTN: Mr. H. D. Lenz, Manager, Engineering North Sandusky Street Mount Vernon, Ohio 43050 ORGANIZATIONAL CONTACT: Gary W. Mizer, Manager of QA and Technical Services TEtEPHONE NUMRED (614) 393-8448 NUCLEAR INDUSTRY ACTIVITY: Engine, compressor and pipeline controls. Parts and maintenance service only; no current nuclear orders.
ASSIGNED INSPECTOR: fh4,5 k^
E. H. Trottier, Reactive Inspection Section (RIS) Date OTHER INSPECTOR (S): W. P. Haass, Pro j , rdination Section APPROVED BY: #fOpf4 E. W.~Merschoff, Chie RIS, Vendor Program Branch Date INSPECTION BASES AND SCOPE:
A. BASES: 10 CFR Part 50 Appendix B and 10 CFR Part 21 B. SCOPE: This inspection was performed to establish the cause of an erroneous engine speed signal that would have prevented a Cooper Energy Services standby diesel generator from starting when required.
PLANT SITE APPLICABILITY: Byron 1/2 (50-454, 455); Nine Mile Point 2 (50-410);
Palo Verde 1/2/3 (50-528, 529, 530).
8604220106 860418 PDR GA999 EECCOES 99900373 PDR
ORGANIZATION: COOPER ENERGY SERVICES MOUNT VERHON, OHIO REPORT INSPECTION NO.- 99900373/85-01 RESULTS: PAGE 2 of 5 A. Inspection Issues The issue that resulted in this inspection was erroneous RPM indication experienced by a number of standby diesel generators supplied by Cooper Energy Services. In addition to incorrect display of engine speed, a faulty RPM signal can prevent the diesel generator from starting when required. During a normal start sequence, the starting air supply is removed once the engine reaches approximately 275 RPM. Thus, with a faulty RPM signal registering engine speed above 275 RPM, no starting air would reach the engine. In addition, there are sundry other alarm and control functions initiated by engine RPM that wculd also be disabled.
B. Inspection Findings Contrary to Criterion XVIII of Appendix B to 10 CFR 50, and Section 18.3 of the En-Tronics Division QA Manual, no records could be found to verify that internal audits had been conducted in 1983.
C. Other Observations and Comments
- 1. Faulty Engine Speed Indication The inspector examined all available documents and conducted several staff interviews to establish En-Tronics part in correcting the erroneous RPM indication that has occurred over the past several years at three nuclear power plants.
Early correspondence between the Airpax Corporation (subcontract supplier of the engine tachometer) and En-Tronic Controls indicates that the problem was initially thought to be in the 21 Vdc power supply for the tachometer. Specifically, it was believed necessary to completely isolate the power supply unit from " noise" (a small, but undesirable ac voltage component superimposed on the dc supply) on the incoming plant 125 Vdc supply by adding a dc to dc converter. In their letter to En-Tronic Controls dated November 9,1983, Airpcx Corporation stated that such de to de conversion for purpose of isolation was not required in the application used by En-Tronic Controls (diesel engine tachometers). Airpax did, however, recommend a change in the ground potential of the tachometer case, such that it be tied to the same potential as the negative side of the incoming 125 Vdc plant power source. Continued pursuit of the technical solution to this problem by En-Tronic Controls and the affected utilities reveals the following:
i 1
l
j, ORGANIZATION: COOPER ENERGY SERVICES MOUNT VERN0N, OHI0 REPORT INSPECTION NO.- 99900373/85-01 RESULTS: PAGE 3 of 5 Arizona Public Service, Palo Verde Station, implemented a plant change request that changed the ground potential of their Airpax tachometers to that of the incoming plant 125 Vdc. This modification was shown to be ineffective when the incoming plant 125 Vdc supply was found to have approximately 30 Vac superimposed on it causing
...the Diesel Generator logic to think the engine is starting...."
On August 3, 1985, Palo Verde Station approved a second modification to reduce the amount of noise on the incoming de supply from 30 Vac to less than or equal to 6 Vac. This modification was based on a laboratory test conducted by En-Tronic Controls that demonstrated the system would tolerate an incomir noise signal of at least 15 Vac without causing diesel generator " engine started" signals to appear.
The problem of false d esel generator engine start signals has not occurred at Palo Verde Nuclear Generating Station since this plant change was implemented.
In September,1984 and July,1985, Commonwealth Edison's Byron Station standby diesel generators displayed engine RPM indication with the engines shut down, as well as a number of local and control room alarms. Since indicated engine speed was above the starting air cut-out speed (280 RPM), any automatic start signal received would fail to " roll" and start the engines. Analysis by station and corporate personnel revealed a faulty annunciator power supply that was imposing a high frequency ac voltage on the common 125 Vdc supply to the diesel engine control cabinets. This problem was remedied by the installation of dc to de converters that effectively separate the incoming 125 Vdc supply from the engine tachometer. No further problems of this type have been reported to date.
Unit 2 at Nine Mile Point has also experienced spurious RPM indication on their standby diesel generators. Station personnel, believing the problem to be a ground fault in the 125 Vdc supply, ran separate, shielded power supply cables to the engine control panels.
As a precaution, a de to de converter was installed to provide additional isolation and prevent unwanted ac from appearing on the de supply to the control panels.
The inspectors noted that while the problems at all three sites were related (faulty 125 Vdc supply causing erroneous engine RPM indication), neither the cause nor cure was consistent. Also, it was learned that in all the standby or on-line diesel engine power systems sold by Cooper Energy Services and En-Tronic Controls, only nuclear standby diesel generator instillations seemed to be affected.
ORGANIZATION: COOPER ENERGY SERVICES MOUNT VERNON, OHI0 I
e REPORT INSPECTION NO.- 99900373/85-01 RESULTS: PAGE 4 of 5
- 2. Internal Audit Program With the exception of the item of nonconformance noted above, the inspector found the En-Tronic Controls Division audit program to be adequate. Corrective actions to previous audit findings were appropriate.
- 3. Procurement Document Control The inspector reviewed applicable sections of the En-Tronic Controls Division QA manual to determine the requirements for vendors to provide En-Tronic with quality products and services. In addition, the inspector reviewed procurement document files and the report of an audit conducted by an En-Tronic Controls customer. Of the three procurement document files examined, only one was found to indicate that the item to be purchased by En-Tronic was evaluated for its safety significance. In the remaining two files, no evidence could be found to establish that an evaluation was conducted to establish an appropriate safety classification for the parts supplied. No objective evidence was presented to the inspectors to show that suppliers were providing the appropriate level of quality in their products and services, nor does En-tronic maintain a historical record of vendor general performance (approved vendor list). Further, it was not clear that En-Tronic Controls performed any inspection of components on delivery. Rather, it was left to field failures to point to components that were not adequate for the application.
- 4. Design Documentation Three nuclear diesel generator design packages were reviewed. The packages included the bid (technical) specifications, drawings, procurement documentation, change notices and miscellaneous letter transmittals between parties to the contract. One significant design change was found and the attendant documentat!on reviewed.
The change resulted from the addition of high wattage diodes to the engine control panel and required extra ventilation to control the panel's interior temperature. Review and approval of the design change appeared to be in order.
t ORGANIZATION: COOPER ENERGY SERVICES MOUNT VERNON, OHI0 REPORT INSPECTION No.- 99900373/85-01 RESULTS: PAGE 5 of 5
- 5. Procedures Internal En-Tronic procedures were reviewed to determine if procedural controls were adequate. The procedures addressed design checklists, quality assurance designations for material, material purchase control, field and shop change orders, engineering responsibilities, and draftsman responsibilities. All procedures appeared to be adequate in content.
.' j '
I %y3 es ] . n . ! S *- '
n M
y i
W w , i i
%;. to' w
t
~
h'aql %
' h cy'i' W l l t'>
bl Ml v
h' m 1
l i . @j s ,'
N i *T. ! 'N.i D'i kiQ l
C 80
- I 'G
+'i 44 49 c4 f
'i ,;$ l C> t m I' g N
~
s, 4 tt i
l i
l9+
i A ^l l-cs [ 9 M t i
{Y
, :5 -
&&q q
\$ b. ' , g v
,*l k
i; ;
. , ' ', l'
-i -
_x v
d -
' 'l G ~ N ,I
- 7. $ k q[a $
~
b ~ i ,<>
s, }l Q % 4 ._
i t ; - I , . - - Q ;y s , - r ' h Vrf i;- - L'*-) 3 , - ,.::. CW :.. M. O t.X J y u Q. 3 w, .. m &. _ g C/ - ?,' c, 0, , s gl . si o
- ,o l- .
mL - , i . j, L,- - sT $- M )% U ' O 8 .T l y i M " .a .$ 'f' )3 ,T v- D~ ) ' '- .o g ',2 2' y a w < ~ ,3 7- .., 3 a C c: s. O o e N=w l T. A <- 9 eJj / r .7 N #* d- c l M v > ,, x- . . ~ g ci b l , ." y - ~ 2 s r.3 y &k .i g j ,,,, . I .! *- 'N v. 'N 3 m , r - yl f .) x V> e .g ! C d,-a[$)l y' L' 6x Y ! e iI) . ! - l , c ; :, d Y yl40n-% , > ' , d d_s % 4 .C U c1 S' ! ') .. *1'- , .q J -d '*- b E/ G .) h i M - t h I r 9( ] , 3 J 1 ;- ,V .A ..) Qw d ')1 m ./ % 4 y3 N. I 2 + 4* -r a y ' W * . s a ; , .. p - q w t- - - a .,' v. c 'J %+ w j - rc- e <*p a b-x -.: z_ - 2 , .w. O 0 Cr .x e & + % .q f.t g' y , -> ne $ d' ~ t-n e- 1 M, '*. 3 .:A C > 4
- 2 --
2' <::t h ~ t 0 u *^ 4 h C-) -- % '~J "~< , E ,? h ,, %' sa a # .- w7 i - d v .%, ..n . O., y (;J , . 'S
- f, 88 W d h C 's Q ,,,'; :#
d Q + . ~~ n'.:- w.s W b O u ' * ,3 , -' . 2 ( - -r A x<ri N W" ~ " ~. W ~~. e ~8 o;j f ., 7 l N12 8i h) Y C I l l l Y N* Ole [ - s.s y \ l \ G ' ll c'* hI ~.2 n I l >- O L~ J a, P c un 9 '- ' r.. 8 9 m N Ag a w I M -2 m .. 3 i 0 g- w u ,2 uhxy .R t2 *oJ e a r 3 k (- P If I ' 'O ' r' v .m
- ', 9 ,
{ 6 C ya2 l J PJ N
- I
- b0
& 0t'$ . 2; * ~ ba ' ' n' O s "Q .) 2 c ~. Q 4 e %r_. tJG' t) 'J a E CU4W 9.} d >' 1 0 ev32 u 9j 2 c 2CO23 - E N h d O f . [ [g_ O k$ye E h @& a Q- ~ Q n.; U Q, .- O c*- Q L4. ta C C.dJ;u$ i. d O*" i N y b b C O oO cdcrOc c Y , if , N.O W @j 2 Q- l q , f f Rh . , hi n N! i i i sfc !! p !+ w i - i i s 3
- v; !e.i i
m N u 94ii %e ! H id i s = e.s i i'
- j. ',. :
d 1[ ! ' 3 f's v4 5 hw I -I .,h ghdpe,g*.g' y( A3\g :t.1,' , & ' '.h s t 4
- .i., .
as % i o $ q ' Q W d 'J iy % f; s)jkhho Nq I
- i m O
u < t l I ehulc 4 m 3 I sm$r as u , y w E
- g !
I T* " Tt - 'iiiiii P .e - i e I : I-d C 9 3 I i O 4 $ ? Y ? ? i 22 2 MC E5 f kbbDiMUObOb$E..jN!$h - J :! 4 4 4 dCidJJJJ4, dad!.!!!!!!! e y g :y u . 1 1 1 ~~ g e-hb&&4,J-d%%,q% ; l# e j$ $ ~ Nl m > in o 4 ~l q 4, :: d .ti O W
- ~w * .
a ; 4 ,. i l e 1 b' ,n o 3 ' 8[,; iw H! o 4
- 4 v N E 1l
!44 .a . s is v k' 4 do ! rw:: i: e< !) 2 ' 44 k ' L'! ) .s j1 1: fi $hu N k d Dl I in ; +1 e ; awa g& e x m' 2 S y. 1, s nt k e a .o N i k,
- 0 s
3 g , sh ;u 1 1 , k : f! @! + Li J
- f, w a a % .h!q
'f, T , t
- w
- d. * '
l g 7 l l ? l
- i,iiii nu q
- a l -
ol - s I ' u o a: - - mi %[c i 2 b Edh..e_$$$Ah .o me= sn C 2 D~ ~ !s d*% t A{wt% e od ,m$ m; o ==s k kbhNUN N bk i k ik U o 7, , ' I %w tb N
- s.j i t
i i i ! i j i l - .n Cl
- O \ . l l . .
O ' i I ! I l I ' i D m l O i 4 l l ; . : I - f o S Hjd, ' I !: I l l l l em 'l %# ! i i hk 4 l l i ' ' I l ' y d kl s 4 i l l l , c00 c wC N y 1 . ; j i l i i [ ' O CK E ' 6 I l f + i i ' i { N c c , l* y} . A h I O o , l U \ b }l . [ 0 3 y t y j t ' I h ! p i i r x J 4 i l l hj b.' l I i tt s 5 i H L 2 N I s A Ag ,U , i d W l l W > . I' w ^ M c W Ch d - l , , '*:, 'i 'I IIIII NV s N l' p l iM a ,,, M ' i. D ol N ) }O*4 1 at c W 3 b' If 37 84 ) ., o WkN Nh Gw .J 2 c " N; , 8 Cy g W J 'l n 2 02225*5 d 2uo25c* 7 O hCh C $ 30 o c e ys nl i ,' \ i
- u. t w
- at; 4 O W @ c. zU HW 55 G2 ~~~ @ M:l m td l Cfc':O g [ $oE.'d;f:~ , i l l ( PERSONS CONTACTED , Company CCbE] /*E .6,Mb" Dates 2 I- ? h'k F6S Docket / Report No.'N M c3 TT Inspector 5%7&ba( Page { of f NAME(Please Print) TITLE (Please Print) ORGANIZATION (Please Print) bJ l.iIt:t 0 d (?AtR S ~u \ $ f ,L. ,J cib..fl.% l H. I) . b w fb.e-c, d%;uu ' s /J3 G . n Q .$ i a . R. L M %O I , % t >c 7 d stGt.I. m - Cn(q, (,, -Q. g ., 6 h. , [ /4Ib, b2. A. h /d Wi A A, :k q f;.tc.,cc - C ,c L. g s, 9 , uid+c,7 % s L4-4,Lu,k L lu u u h-Tleo u, !/wsi, ( ! , ;-\ 7 % ' T ,<:1 o s n'3 v ./ -