NRC-87-0075, Forwards Addl Info Re NRC Assessment of Licensee Measures to Mitigate &/Or Identify Potential Degradation of Mark I Drywells.W/Four Oversize Drawings

From kanterella
(Redirected from ML20215E631)
Jump to navigation Jump to search
Forwards Addl Info Re NRC Assessment of Licensee Measures to Mitigate &/Or Identify Potential Degradation of Mark I Drywells.W/Four Oversize Drawings
ML20215E631
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 06/15/1987
From: Agosti F
DETROIT EDISON CO.
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20215E634 List:
References
CON-NRC-87-0075, CON-NRC-87-75 NUDOCS 8706220051
Download: ML20215E631 (12)


Text

!

. ~

c :

&ffQf Fermi 2 Edison EEn *# ta. .

0801.15 ,

l June 15, 1987 i 10C-87-0075

]

U. S. Ibclear Regulatory Comission Attn Document Control Desk Washington, D. C. 20555

References:

1)- Fermi 2 tE Docket No. 50-341 tE License Ib. NPF-43 '

2) 10C Letter dated March 12, 1987

Subject:

Potential Dearadation of Mark I Drywells Reference 2 transmitted the NICs request for a-lditional information-assessment of Licensee's measures to mitigate arrl/or identify potential degradation of Mark 1 Drywells. This request was generated based on the observation of water coming from the drains connected to a sand cushion located between the Drywell wall and the surrounding concrete at the Oyster Creek tbclear Generating Station.

In conpliance with Reference 2, the enclosed information is being submitted in accordance with 10CFR50.54(f) .

If you have any questions, please contact Steve Frost at (313) 586-4210.

Sincerely, D .' M F. E. Agosti 62f$$h$70615500gi' Vice President p Nuclear Operations Enclosures cca Mr. A. B. Davis h Mr. E. G. Greenman g g Mr. W. G. Rogers ;3 6\

Mr. J. J. Stefano Q .H g

\\\ q

USNBC June'15, 1987 NIC-87-0075 '

Page 2

\

I, FRAE E. AGOSTI, do hereby affirm that the foregoing statements are based on facts and circumstances which are true and a: curate to the best of my knowledge and belief.

4W. 1 F. E. Agosti Vice President l Nuclear Operations On this 8 day of /M . 1987, before me personally appeared Frank E. Agosti, being first duly sworn and says that he executed the foregoing as his free act and deed.

A l-<ubus .

1 l

Notary Public I w.4 us,s Notary Public. Washtenaw County, Mi

% Commission Expires Dec.4 ]jlp g FO fr#

%s, , n )

1 l

I I

l i

I Enclosure to NBC-87-0075 Page 1 NBC Item 1 Provide a discussion of your current program and any future plans for determining if the drain lines that were provided at your facility for renoving any leakage that may result from refueling or from spillage of water into the gap between the drywell and the surrounding corcrete or from the sand cushion itself are unplugged and functioning as designcd .

respocae to Item 1 Fermi 2 has four drain lines that can be used to renove noisture from the sand cushion located between the Drywell wall and the surrounding concrete. (See attached drawing 7M721-2219) . These four drain lines are 11/2 inch schedule 40 galvanized steel. There is a P-trap on the end of the pipe. The drains are filled with sand up to the P-trap. A sanple of the sand will be taken during the first refueling outage.

This would be the appropriate tine to perform this test since the fuel pool areas will be flooded. If any leakage were to occur this would be the nost likely time. Once the sanple is taken, it will be tested for noisture and the presence of'any contaminates that would result from corrosion of the drywell steel. In addition, the ends of the drain lines will be visually examined to determine any evidence of past leakage from the sand cushion. Further recommendations pertaining to any additional or future actions will be' based upon the results of these examinations.

The drain lines located in the gap between the Drywell and surrounding concrete have been visually inspectcd and fourd not to be plugged and functioning as designed. A nore detailed discussion of Detroit B31 son's future plans for these drain lines is discussed in the response to IEC Idditional Item section contained in this letter.

NFC Item 2 Provide a discussion of preventive maintenance and inspection activities that are currently performed or are planned to minimize the possibility of 3eakage from the refueling cavity past the various seals ard gaskets that might be present.

Enclosure to NIC-87-0075 ;

Page 2-Iksoons_e_tg 2 pp_2

'The Drywell seal bellows drain enpties into a manifold which is equipped with a sight glass. This sight glass will be monitored daily when- the refueling pool is flooded in order .to detect any potential .

leakage of water. If any leakage is detected, Operations will evaluate and determine if the water is going to the space around the -

Drywell shell. In addition, the sand cushion drains will be _ _

periodically nonitora3 for signs of noisture. Procedures will be developed or revised to incorporate the subject actions prior to filling the refueling pool.

NIC Item 3 Confirm the information listed in Table 1.of Generic Letter 87-05 is correct' with regard to your facility.

Resoonse'to Item 3 Detroit B31 son has reviewed the information in Table 1 of Generic Letter 87-05 with respect to Fermi 2. In the colunn title " Gap Material".it states " foam." To be more accurate, the gap material used at Fermi 2 is Polyurethane ' foam. The otter information listed for Fermi 2 is correct.

NIC AdditipDpLiggm_

Mark I owners whose design is such that tre sand cushion is open to the gap between the drywell and surrounding concrete were required to submit additional information.

Resoonse to Additj9D31 Item This additional information is supplied in the most part in the response to the NIC Additional Item below. Fermi design does have tre open gap between tre drywell and surrounding concrete. Drawing

'6C721-2358 and 7M721-2219 (attached) shows the design enployed by Detroit B31 son for the subject area. In addition, Figures 1 and 2 (attached) show the current Fermi design and the Oyster Creek' design of the drain system. It can be seen that the Fermi Design contains nore drain lines which provide for better drainage.

Enclosure to NIC-87-0075 Page 3 NIC Additional Item _

Provide any plans for performing ultrasonic thickness measurenents of the drywell shell plates and adjacent to the sand cushion or any other i proposed actions to ascertain if plate degradation has occurrM. I Since the degradation that has occurred at Oyster Creek is localized, sufficient details should be included to show that the sanpling basis for ultrasonic thickness neasurenents is adequate in terns of size and test location.

Response to NIC Additional Item Drawing 6C721-2358 (attached) shows the subject area. In order to ultrasonic test (UT) the drywell plates adjacent to the sand cushion, l concrete would have to be cut, removed and then replaced once the UT was over. This process is neither feasible nor would it be advantageous for the reasons indicated below:

First, the design of the refueling bellows assenbly minimizes the possibility of leakage into the drywell gap. The leakage of the l drywell to cavity seal bellows during refueling was considered to be a '

source of leakage into the sand cushion at Oyster Creek. The

- refueling bellow assenbly forms a seal between the drywell and the refueling pool to permit floodhg of the refueling pool. The drywell seal bellows at Fermi 2 exterda from the drywell shell out to the refueling pool and consists of 3 cylindrical, one piece stainless steel bellows (drawing SM721-2169 attached). All seal boundaries consist of welded steel and contain no active conponents.

Secondly, a different type of coating is utilized at Fermi 2 for the exterior of the drywell. At Fermi 2, the full length of the. exterior surface of the drywell is coated with Carboline Carbo Zine l!. (drawing B2-93 69-5562. This is a self-curing zinc-filled inorganic two-part basic zinc silicate complex supplying galvanic corrosion protection to steel surfaces in marine environnents. The coating is insoluble in water and resistant to aggressive water and solvents (UFSAR subsection 6.2.1.6 attached). The polyurethane foam sheets located within the drywell gap are coated 'with an epoxy resin binder (on both sides), to prevent water leakage into the foam (Epecification 3071-48). In

! addition, the Fermi 2 drywell, in the vicinity of the sand cushion, is 1.5 inches thick (drawing SC-721-2701 attached).

_ _ - _ _ - _ . - _ _ _ . - - _ . - _ _ _ _ _ _ _ _ _ . _ _ _ . _ _ _ _ ____. __ _ _m__ ______.__m._____________ _ _ _ _ - _ _ _ - _ _ - _

Enclosure to.

NIC-87-0075 '

Page 4 Third, a walkdown found no recent irdications of noisture in the sand cushion drain lines.

Fihally, the area directly below the drywell seal bellows contains a

-2* drywell to reactor well seal drain, a 2" liner drain, and a 4" drywell seal rupture drain (Figures 1 and 2 attached). Should tre refueling bellow assenbly fail, this design minimizes the possibility of water leaking into the sand cushion. Instead, the leakage would enter these drain lines.

l

FERMI2UFSAR 6.2.1.6 Materials C. genic materials used in the Fermi 2 primary and secondary con-tainments have been selected for extended life during normal operation and for resistance to expected accident environmental conditions. Thermal insulations used are inorganic and are not sensitive to high radiation fields, steam, or high temperature.

Table 6.2-8 lists the type of protective coatings used, their thicknesses, and their locations within the primary and secondary containments.

Table 6.2-9 lists organic materials used for wiring insulation in the primary and secondary containments.

Table 6.2-10 lists other organic materials of significant quantity and the amounts used in the primary and secondary containments.

Evaluations of these materials have been made. It has been determined that they will satisfactorily endure accident environ-mental conditions and that their expected products of decomposi-tion, if any, will not adversely affect the operability of any ESF system.

gyp, The following paragraphs describe the coatings and paint used i within the primary containment, including pertinent information regarding the following:

a. Identification of material used, location, and function
b. Physical and chemical characteristics
c. Performance under accident conditions including wash-down, radiation, steam, temperature, and jet impingement effects
d. Data on effect of any coating material that may be dissolved or carried by the fluids that flow in the spray systems of the ECCS that may affect the function-ing of the systems
e. Effect of coating on core and heat exchanger heat-transfer surfaces )
f. Clogging and other effects on fluid flows in Class 1 systems from coatings.

Additional information is available in Reference 17.

i Reactor Vessel Support Pedestal The inside and outside surfaces of the reactor vessel support l pedestal are coated with Ameron Nu-klad surf acer 110 AA primer 6.2-45

I 4

FERM12 UFSAR f

j

~

and one finish coat of Ameron polyam ide epoxy 66. The function of _. this coating system is to protect .ard seal the pedestal surf aces against attack by either domineralized (aggressive)- .f water .or radiation contamination and to f acilitate washdown.

The physical and chemical characteristics of the Ameron Nu-klad surfacer ~110 AA primer are excellent adhesion to, clean concrete ,

and good adhesion to steel, resistance to attack by demineralized {

water or hot condensate,. excellent abrasion resistance, consider- 1 able radiation' resistance, excellent chemical resistance, and I indefinite repairability. . Both primer and finish are modified f epoxy. . Ameron polyamide epoxy 66 has properties similar to those of the primer. Both coatings withstand temperatures to 200*F' '

continuously and'to 300*F intermittently. j Required DBA testing has been performed, and the coating system is capable of withstanding the rigors of a LOCA. A washdown  !

removes contamination.- 1 The coating effect on the. core and heat-transfer surfaces.is l negligible because the coating system is nonleachable. t No clogging or other effects on fluid flow in Class 1. systems are expected since the coating is nonleachable and has excellent -

adhesion.

The Ameron 66 top coat has been applied in accordance with the recommendations of Regulatory Guide 1.54 and ANSI 101.4 and.the system has met-the pull-test requirements of ANSI N512. The coating of the reactor vessel support pedestal and other concrete surf aces within the RCPB has been designated as a QL Level 1, safety-related activity. The coating system as described above is a qualified coating.

Drywell Concrete Floors and Walls The concrete surfaces of the drywell floors and walls are coated l with Ameron Nu-klad surfacer 110 AA primer and a top coat of Ameron polyamide epoxy 66. The function, physical and chemical  ;

characteristics, and other properties of this coating are dis- l cussed under " Reactor Vessel Support Pedestal" above.

Sacrificial Shield Wall The exterior surface of the sacrificial shield is coated with Carboline. Carbo.Zine 11 applied over a blasted surface. The repair of coating work on the sacrificial shield wall is per-  ;

formed by power-tool cleaning to a minimum visual criterion of .

SSPC-SP-6,'followed by a coating of Carboline Carbo Zinc 11. l This is a self-curing, zine-filled, inorganic, two-part basic 1 zinc. silicate complex that readily accepts top coats. The function of this coating is to provide long-term protection )

against corrosion, attack by radiation'or radioactive water, and to facilitate washdown.

6.2-46 i

I 1

FERMl 2 UFSAR J

The physical characteristics are a hard surface resistant to aggressive water, very good impact resistance, and a temperature use range up to 750*F continuous and 800*F intermittent. Flexi-bility is fair. Chemical characteristics are insolubility in water and resistance to aggressive water and solvents. Rela-(0-200'F) and humidity tively w(ide ranges to 95 application percent) temperatures are permissible. j contaminants on the coated surface can be easily washed down with water. The coating has high radiation resistance, resists steam to 180*F, and has excellent temperature resistance up to 750*F.

The coating has no effect on core heat transfer or heat exchanger heat-transfer surfaces since it is not soluble.

Carbo Zinc 11 coatings have been subjected to extensive DBA test-ing for a variety of application techniques and were found acceptable for use in BWR environments under LOCA conditions.

These test results are contained in Report No. 56878 issued by the Carboline Company, entitled " Carboline /ORNL Round Robin DBA Testing - Test II."

Design-Basis Accident Test Report No. 56878 indicates that some particle separation could occur under accident conditions in areas subjected to continuous scouring by water and steam spray.

Such scouring would occur only in the immediate vicinity of a

$" pipe break and within a few feet of the containment spray As headers. In such areas, the coating is not lost in large flakes, however, but rather in particles less than 20pm in size. The report further states that the particles are water insoluble and do . tot clog screens. The dry density of Carbo Zinc 11 film coat-ings is three to four times chat of water. Based on the size, dens'ty, and possible flow paths, potentially disbondable par-ticle,t would in all probability settle to the bottom of the dry-well tr suppression pool during a LOCA. In the highly unlikely event of all such disbondable particles migrating to the ECCS I suction strainers in the suppression pool, it has been determined I that no clogging effects or degradation of emergency cooling l equipment would occur.

l Most of the Carbo Zinc 11 coatings in the primary containment I were applied in accordance with the original 1969 specification, prior to the issuance of Regulatory Guide 1.54 and ANSI 101.4.

The industry standard at that time was to apply Carbo Zinc 11 in accordance with the manufacturer's recommendations. This type of coating has been successfully used in operating BWRs and for years has withstood a , variety of adverse conditions.

Drywell Interior Steel All exposed interior surfaces of the drywell pressure boundary, including the drywell jet deflectors and surfaces in contact with concrete, are coated with Carboline Carbo Zinc 11. The repair of coating work on the interior surfaces of the drywell is 6.2-47

(

FERMI.2UFSAR l

performed by power-tool cleaning to a minimum visual criterion of )

SS PC-S P-6. A coating of Carboline Carbo Zinc 11 is applied over ,

this surface. The function of this coating system is to protect l the surfaces from corrosion, from attack by aggressive water, l radioactive water, or radiation, and to facilitate washdown.

Those coatings Which cover the drywell pressure boundary are maintained under Fermi 2 QA Level I criteria to ensure long-term corrosion protection for the pressure boundary. This coating is not considered to be in full compliance with ANSI 101.4.

Drywell Interior Structural Steel The primary structural steel within the drywell is coated with Carboline Carbo Zinc 11. Surface preparation included sand-blasting to near-white metal. The purpose of the coating is to provide long-term protection against corrosion and to facilitate washdown.

Substantial modifications ,were made to the primary structural members in two separate phases due to load reevaluations that resulted in varying degrees of surface preparation. Welding and nondestructive examination procedures necessitated removing existing coatings at tie-ins and welded connections. Due to completed installation of equipment, generally very tight working quarters, and complex components placement, sandblasting and 'T recoating of steel members was not routinely completed. The .J coating of structural steel is not a saf ety-related activity.

Surfaces of Suppression Chamber The interior. surfaces of the suppression chamber, including the interior and exterior surf aces of the downcomers and vent header, the exterior surf aces of the vent pipes, vent header supports, ring girders, catwalks, monorail, stiffeners, supporting steel, piping, hangers, and penetration nozzles, are coated with the Wisconsin Protective Coating Plasite 7155 system. The Plasite coating is a water-resistant phenolic coating cross-linked with epoxy resin and polymerized with an alkaline curing agent. The function of this coating is to provide long-term protection from f corrosion and radiation, and to facilitate washdown. )

f I J

I Plasite 7155 resists temperatures up to 400*F intermittently, develops good hardness and abrasion resistance, can withstand cyclic thermal shock, and provides a broad range of long-term chemical resistance, i

The coating was applied in accordance with Regulatory Guide 1.54, j ANSI 101.4, meets pull-test requirements of ANSI 5.12, Sec-tion 6.2, has been DBA tested, and is considered a fully quali-fied coating capable of withstanding accident conditions. Its application is a safety-related, QA Level 1 activity. ) 4 6.2-48

, y g ,g I i t  :, _ s , 4 matmumyofr,h~N  ! N s

, y, y :r,e,ea . r...e_

rva cc,o 5 se co v: r>c. .T se ==c

- ce<e.g. n...noer.e se

&^ M d4~5

_' . ttPM . f n *;; .P.%.'

Figure 1 i ii ' '

l n - - m _

~ ,,g ----d

( i p C ,

, bcoW5T. JT. hI.(,(,f b*4

" b nmna. m mu.m x N

~

> 2 m ; b.T C.H% ,.7, (by of,4eas) .. ,

. \

( G ' C'% c 12EAcToe.

i

t. J' X 5" DtA. AT AtlW(ITH 3 I

.

  • Ds2AIN T'(A CU PNES f20*(124* W O"E"O

, ( }

-4_ e ) I -

0M D C

3 y C - Z.'.tk 52 t.d -

6TIF F. ( A M) s x '

, l .

?.LjG C,C'.i rI

._ 9 ' --

l . / -T Tf. ('tE.M8vE.

rf.t' eAb. \ IW F IE.LP) .

,f, 7. rva fy i

-- I }

~ 4'O HOLE AT '-' % g  %' e

,,2 d 2, ,6 5.) 2 REQ't? '

pypoz o- _

g e, E . u.w esar. tmarneso 3 -

g

. hec s

\

r -

mm._

M (-SNAr .

i 4

-*=i 18/* 5* R t a l'15,44M d PRYFN.K '

  • m * '

mi .

J. , -

' cm u m.av.tue.

DEAtu TTP(4)MAC4's

. (m sta m ) CS - --

7" _

t

[.# ..

? ON PfNS$r(. *EMEP ie NpE.m'." N N. '.' <

, T(g;;g*) Mk Largh muTs iz Giunedo)!.

Tc, at - -

,,3g

GE AB/WD IN PLACE) .

M SECTioW 11-11 a.M s

m. ,w - 6 0 %,i g g i ,

~

&N

. , ' APP *Ov4 Inf

- . . , - .; . :- ggpa f,r" w

.~

  • m

- ,e e . . . . . . . .

$gP g ,

, K , - -

WW Mr -

~ss persas muste* to ms mcuart ava um venne n mism an as s -

  • / a.auw m
  • d .>S 1 h /A.4 W*s1'.>4*, 'av.t r ygg3 g gegyggs 33 secuart WWEDE. gg "$',Wni g. ,"-

..p,g,% -

, S m.d.. % - i

. 2sm f.Y -

{-l lt W.f.'t.

%%s Q'IU"?"*@.~'fTA"t l > . .e .T %W, .- e . . . 4. _ . .

Q

, .f

!.* *, yyjgg/gg, -

, meneENT 6 s nDs

.e.

em

. mass. _, 'h. ..f.. ,._,...

. m . ,- 2,,

W3.sfh)e .*L, ' Y6. $ .

'6 -

. = ==== ,

seus t"

  • 't*M*l DOCUMENT CONTROL NO.TZ9 OO O 000 9A '#47 *
  • M Th~3C , .M'.M . ..

R!EIA!CT WUDG) IPIOdt.)

l iL.ll)!! 19E!CTi {g lcrTid9

- . . .m SE J . .

.# ' ' ' " ~ "  : mm Jpose:. vsn' . M macses.n

    • ' St,Ak 4e tS Wha.s 8mvd-<1-T3 e um*em, . ,.
h. - 1,1. ' -

m""**** " , ,Sr 2

. ' ~ ~ ** * ' " * * * * " "" '

AT AZNUTH 120 .W SECTION IMI . . -* '

3' ' ~'

PER' DCN M8:4

~

' ' ' ' ~ . , . ' ' s' -

%* ~ ,, .. _ .

- s-- - r'

= . * = -- - - ,.=*-== == .a s ..

....1...-- [

wObMAo mw o L u .w ny e At>be / i d, .

_. C*T . 4 i

masi, mm. eea.a e.

p, g _ m l-

== . a= ==.I

-l-man. ==;

.~

=

'.. y 4 ,'- comone,seasc*w= g -eavs. -

l TIGURE 2

,o i

MP PATE P

,,, s /-

k

<g 'k' l  ;

PTotacnvg ~ T[*e 4Hiuotwg ,'

v' l ,.

}

l

[,

/DRVW.1,1, k

. r '

l l -enu e u w, 4gxxx x x I x .xdaurAl. l g

i l,', @N

\'

\  :

Pl.Att l

.- l i

I l l  %

',0,3

<f DRAIN l wgig l '

l 3 MAM!A4. l [: ,

l p i i

i

'N %

, i

> f hity, f  ! DRYWtt L To

k. 4

. J ' d t'- ?4ts . , i l

7i'5 ~ f DR Alw CAVITY SE.AL g.

l Y

t -

OYS TER CR.EEK