ML20101Q770

Rev 1 to Safety Evaluation Re IE Bulletin 84-03, Refueling Cavity Water Seal

ML20101Q770
Person / Time
Site:	Salem
Issue date:	12/17/1984
From:	Public Service Enterprise Group
To:
Shared Package
ML20101Q757	List: ML20101Q755 ML20101Q770
References
IEB-84-03, IEB-84-3, NUDOCS 8501080280
Download: ML20101Q770 (19)

Text

%

S-C-N300-MSE-285 REV. 1 Pcg3 1 of 13 Date 12/17/84 Public Service Electric and Gas Cornpany P.O. Box 236 Hancocks Bndge, New Jersey 08038 Nuclear ()epart ks, '

7 TITLE: IE BULLETIN 84-03: I REFUELING CAVITY WATER SEAL 1.0 PURPOSE The purpose of this Safety Evaluation is to evaluate the }

potential for and consequences of a refueling cavity water [

seal failure as requested by IE Bulletin No. 84-03. 4

• i

2.0 SCOPE

,i

~ ~_ k This Safety Evaluation and its conclusions are applicable to both Units of the Salem Nuclear Generating Station during a re fueling outage. .

3.0 REFERENCES

IE Bulletin No. 84-03: " Refueling Water Cavity '.

3.1 -

• Seal", August 24, 1984.

3.2 Operating Plant Experiences 8-27 OElll7 " Connecticut Yankee Leakage Past the Reactor Cavity Pool ieal".

Telecon From C. R. Gerstberger to G. Dillion August f 3.3 j:

24, 1984 " Connecticut Yankee Sealing Ring Incident".

3.4 PSE&G Design Calculation, S-C-N300-MDC-079 "Ef fects  ;

of a Gross Seal Failure of Refueling Cavity Water 4 Seal".

3.5 PSE&G Safety Evaluation SGS/M-SE-037, " Inflatable Reactor Cavity Refueling Seal Restraints".

i Sandia Laboratories Roport: " Spent Fuel Heatup 3.6 Following Loss of Water During Storage", March 1979.

3.7 Maintenance Procedure, M8H, " Reactor Cavity Inflatable Seal Installation and Handling". ,

3.8 Maintenance Procedure, M8C, " Reactor Vessel Head and Internals Removal and Installation".

3.9 Operating Instructions II-8.3.8, " Emergency Filling of the Spent Fuel Pool from the RWST".

f 3.10 Operating Instructions II-8.3.1, " Filling the Spent i Fuel Pit".

l kDkIkh0[80841219 EDD-7 FORM 1 REV 0 10 SEPT 81 G 05000[ w a.:v> w

r .

vi

• - Pcg3 2. of 13 4 S-C-N300-MSE-285, REV 1 Dato: 12/17/84 1, U

3.11 212358 A 8874, " Refueling Canal Inspection Plugs and Structural Concrete Forms m ^

J

_ s. W W r ; '.) ;

3.124.2SS21Y Ae 8760, " Demineralized Water Make Up". j' 91s4WE -

3.13- 2'05229?A 8761, " Chemical and Volume Control Boric h Acid Recovery" .  ;

q 3.14 205230 A 8761, " Chemical and Volume Control Primary Water Recovery".

3.15 205234 A 876'0, " Safety Injection". ]

3.16 PSBP 112177, " Reactor Vessel Cavity Seal Assembly ,l and Details". (

M 3.17 PSBP 145161, " Fuel Assembly Outline and Reprocessing . . I' Drawing".

3.18 PSBP 148820, " Spent Fuel Module (9 x 10)".

3.19 Technical Specification 3.9.5, " Refueling Operations '

- Communications". r 3.20 Technical Specification 3.9.8, " Refueling Operations .

- Coolant Circulation".

3.21 PSE&G Alarm Book.

n Letter to Mr. Theodore Hollander, Jr. from R. T.

3.22 Stanley dated November 6,1984 entitled " Refueling Cavity Water Seal. " j

4.0 BACKGROUND

On August 21, 1984, the Connecticut Yankee Haddam Neck plant experienced a failure of the refueling cavity water seal with the refueling cavity flooded. The seal assembly consisted of an annular plate seal ring (approximately two feet across) with two Presray inflatable seals to fill two inch openings on either side of the seal ring (See Figure 1). The outer seal was subject to a gross seal failure which allowed 1/4 of the seal to fall through the. annulus. .

Contributing factors to the failure were'the inflation

. pressure, use of lubricants, and the size and configuration of the gap to seal dimensions. These conditions resulted in bowing of the top of the seal which allowed it to be pulled through the annulus.

EDD-7 FORM 1 REV 0 10 SEPT 81

if-

• Pag 7 3 of 13 S-C-N300-MfE-285, REV 1 Dato: 12/17/84 The seal failure caused the refueltag water cavity to drain its. entire 3 volume, approximately 200,000 gallons, in 22 minutee m No' fuel had been in transfer at the time of the fa'ilu  !}.IfDfuel had been in transfer, it could have been parti o completely uncovered with possible high tj'r radiattientlevels. If the fuel was exposed for a significant amount of time and allowed to increase in temperature, the possibility of fuel cladding failure and release of radioactivity may exist. Furthermore, if the y fuel. transfer tube had been open, the spent fuel pool could i have drained to a level which may lead to the uncovering of <

the top of the fuel. t

5.0 DISCUSSION

N

)*,

5.1 DIFFERENCES The refueling cavity water seal used by the Salen Nuclear General 1ng Station is only slightly similar in design to that used at Haddam Neck. However, thera are great dif ferences in the dimensions, material, and utilization of the seal.

~

The annulus surrounding the reactor at the Salem . i Station is much smaller than that at Haddam Neck, twor :

inches as opposed to two feet four inches, therefore no seal ring is necessary. Only one Presray inflatable refueling seal is used to form a secure closure between the reactor vessel seal ledge and the .

cavity wall. Prior to the inir.ial installation of i the seal at the Salem Station, the cavity wall ledge '

was beveled to a 20* angle, the same angle as the wedge portion of the seal. This produced a ,

+

dependable cavity wall seal surface by providing an area contact as opposed to the line contact seen at Haddam Neck. If the seal becomes dislodged and begins to slip, the beveled area also provides an increase in frictional contact. This increased frictional contact will aid in retaining the proper '

placement of the seal. Many additional precautions i were taken at the Salem Station prior to the initial use of-the Presray seal. Any irregular or interupted seal surfaces.were reconditioned and backfilled.- All local annulus surface conditions of weld' splatter, i grout, rough or sharp m'tal e edges were removed. The l cavity wall side was machined to smooth and contour i the surface. 'The reactor vessel seal ledge side surface was hand deburred and cleaned. All this was completed to provide a snooth surface finish  ;

necessary for inflatable - seal support, protection  :

and seal surface development. I I

EDD-7 FORM 1 REV 0 10 SEPT 81 I

an h,

• Pcgo 4 of 13 S'C-N300-MSE-285, REV 1

- D2to 12/17/84 j;i l The inflatable portion of the seal at the Salem

~

)

Stationvis-exposed to a greater amount of surface q l area from the annulus walls, 2 1/4 inches on

~ 'I '

_~~7 Widecna' d full length contact on the other side 'd c

. - "i ,. yFigu're 2). Connecticut Yankee has an equal

- amount of surface contact on each side, 1 5/8 d inches. Thus, the seal at the Salem Station will balloon out only on the reactor flange side while the .)'

seal ~at Connecticut Yankee will experience this on both sides. At the Salem Station less directional 2

force will be exerted on the seal that tends to pull j the seal downward. Therefore, the annulus design at 1 the Salem Station leads to an increase in the margin j a

of safety. .-1 In addition to the dimensional dif ferences in the 1) annulus at Haddam Neck and the Salem Station, the .. Ly b

seals themselves differ in size. The seals used at d f the Salem Station are 4 inches wide across the top wedge portion, as opposed to 3 1/2 inches at Haddam .

Neck. Both of these seals are used to secure a two inch area.- Therefore, the seal size will aid in ' -

prohibiting the seal at the Salem Station from pulling through the annulus. . ,

~ ~

The material dif ference between the seals also increases the margin of safety at the Salem Station.

The Salem seal is 60 durometer, while the seal used at Haddam Neck is 40 durometer. This increase in s_

hardness will assist in the prevention of the seal ~t U

failure. The hardness will impede the seal from "

bowing and bending and therefore hinder it from being pulled through.the two inch annulus opening.

Prior to each installation of the seal at Haddam Neck, a lubricant such as silicone grease is applied to the annulus. This is done in conjuction with the air tight test that is performed to test the seal for i proper seating. This lubricant will actually aid in the failure of the seal by reducing the frictional resistance the seal would experience from the annulus wall., At the Salem Station no lubricant is used, thus reducing the chances of seal failure.

• To further-increase the safety margin at Salem Stations, brackets are placed on top of the Presray seal ( Re ference 3.5) . No such brackets are used at Haddam Neck. Haddam Neck does utilize a seal support, but this is employed only during the initial It does not aid in retaining placement of the seal.

proper positioning or support the seal during use.

EDD-7 FORM 1 REV 0 10 SEPT 81

.I' Ni P go 5 of 13

• - {

S-C-N300-MSE-285, REV 1 Dato: 12/17/84 s The brackets at the Salem Station are a minimum of  ?

threeginches in diameter, therefore fully covering u t reactoc cavity annulus of two inches. The []

~

lonalrcoverage of the brackets will reinforce T sepitcapabilities. The brackets are used to h; ;'

assures.that the inflatable refueling seal will not  ;;

become dislodged from the reactor cavity seal ledge. G The use of brackets also aid in the prevention of @ ,

bowing of the top of the seal. A '

Possible failures of the Presray seal used at the ,

Salem Nuclear Generating Station have previously been reviewed in a Safety Evaluation. The results s ,

provided necessary assurance that the seal will -

function as required without the possibility of E}

dislodgement from the reactor cavity seal ledge Sg

. (Re ference 3.5) . -

s:

Maintenance procedure inspection hold points will furthur assure the inflatable seal is in proper position. The procedure for the reactor cavity seal '.

installation (Reference 3.7) contains Supervisor / -

Witness inspection hold points and twice confirms '"7 - ;

proper placement of the seal. The seal is first . t inflated to a pressure of 10 psig and inspected for positioning.

If the seating is acceptable, the . .

pressure in the seal will then be increased to 30The psig and again reviewed for effective seating.

reactor cavity water level is raised with a i Supervisor / Witness present and the validity of the 'i sealing is verified with the Control Room assuring w. 'o that there is no abnormal running of the Reactor Sump l Pump. These added precautions are taken to further 4 assure the reliability of the reactor cavity seal.

Because of the many differences in dimension, material and utilization, and the nwmerous additional levels of safety at the Salem Station, we forsee no in .

reason why the use of the Presray seal will result 49 a gross seal failure. r 5.2 TEST RESULTS The qualitative assertions made in o,ur The mostevaluation are significant'is

.very significant assertions. The Connecticut Yankee R the hardness of the rubber. I seal was made of a soft pliable 40 Durameter rubber, Salem uses a which "gives" when loads ~are applied.

EDD-7 FORM 1 REV 0 10 SEPT 81

)

PEgo 6 of 13 $

l

)

S-C-N300-MSE-285, REV 1 Dnts: 12/17/84 hard 60 Durameter rubber which is not pliable and does;not give. To provide quantitative data we have

. 1 performed-a load test on a section of a seal ring.

We e have:, determined that the load required to push the .~

- sealdthrough:the annulus gap that we have in our '

reactor cavity is substantially greater than the J.

weight of water on top of the seal during a normal refueling. The first test ,erformed consisted of a <

one foot long uninflated segment of the seal which '

l was placed in a jig to determine the pull-through loads as shown in Figure 4 attached. ,

i A downward load of 1,100 lbs. was applied to the test -

specimen to simulate a water head of approximately .t 120 feet. We found that during the test that there i was minimal bowing (less than or equal to 1/64th of an inch) on the top flange of the seal ring. The it R

U test was discontinued at 1,100 lbs. because of 1 [

concerns with the adequacy of the test rig for loads R greater than 1,100 lbs.

A second test was performed with a modified  ;

arrangement (Figure 5). This time a 1 inch bar was -

used to apply 2,250 lbs. downward force at the top of -

a 6 inch long segment of the ring. This downward -

force is equivalent to a static head of 480 feet of water over the 1.8 inch gap. Again, the test was.

discontinued as a result of concerns for the adequacy of the test rig. Some deformation did occur, but g

there was no pull-through nor was there any permanent :p deformation nor damage beyond some surface cuts and scuffing (see Figure 6).

The inflatable portion of our seal is 1 1/2" wide and

• the upper half of the inflatable seal is located in the 1.8" gap of the reactor cavity annulus area.

Consequently, when the seal is pressurized the deflection of the upper half of the seal is very limited. After installation and pressurization no '

concave bowing has been noted; on the contrary, through observations in past refuelings, a slight convex' bowing has been noted.

Actual measurements-were The taken of the Unit gap measured between'l.6332 re fueling cavity gap.This is below the value' assumed in and 1.800 inches.

the previous qualitative analysis, 2 inches.

EDD-7 FORM 1 REV 0 10 SEPT 81 .

~ .

M Pago 7 of 13 #

S-C-N300-MSE-285, REV 1 Dato: 12/17/84 5.3 GENERAL INTRODUCTION ex m 4 Although a gross seal f ailbre during a refueling. d. j a E.

. operation.is highly unlikely to occur, the  ; '

consequences of this event have been evaluated. The flowtate of the liquid through the annulus would vary I

according to the height of the liquid. In the case  ;

of the Salen Nuclear Generating Station, if the 4 entire seal were to fail the maximum flow rate would j be 104,000 GPM (Re ference 3.4) . <

The time to drain the volume of liquid to the level #

of the seal would depend on a number of items I including the percentage of the seal which fails, if the fuel transfer tube were open to the Transfer . .)

Pool, and if the canal gates were open to the Spent Q Fuel Storage Pool. Assuming the entire seal failed, ,,

it would take 4 minutes, 47 seconds to drain the Refueling Area alone (248,000 gallons). In order to drain both the Transfer Pool and the Refueling Area .

(332,000 gallons total), the fuel transfer tubeIf mustboth be open and 6 minutes, 23 seconds must pass.

the fuel tra.nsfer tube and the canal gates were open,, .

the time to drain the Spent Fuel Storage Pool, ,

Transfer Pool and the Refueling Area (525,000 gallons _-

total) is slightly over ten minutes (Re ference 3.4) . -

5.4 FUEL IN TRANSFER The worst case possible resulting from this failure y situation for fuel in transfer would come about if .j four fuel assemblies were between the Reactor and the Transfer Pools two in the Rod Cluster Control t

carriage compartment (included in analysis although R .f no longer used at Salem Station), the third in the 1 j upender, and the fourth fuel assembly in the If an assembly were in the manipulator crane. -

upender, it must be layed down to prevent exposure.

Any fuel assembly that may be in transfer at the time ,

of the seal failure must either be returned to the reactor or placed in the upender, if available, and set down. If the assembly were half-way through the transfer process, it would take less than five minutes to move'the assembly to either safe .

position. The top of the assembly in the Rod Cluster Control' carriage compartment would become exposed to the atmosphere.

EDD-7 FORM 1 REV 0 10 SEPT 81

.-l pig 3 8 of 13 ,

sa S'C-N300-MSE-285, REV 1 Dato: 12/17/84 .

With no operator action cladding damage may occur to the3 fuel assemblies in the manipulator crane and in j the; Rod -Cluster Control carriage compartment. An *

~ estremely., conservative estimate for time to cladding This damager would be two hours (Reference 3.6) .

estimate is based on an analysis done for a full core [

unloading in an emptied spent fuel pool. As a result 'N of the differences in number of fuel assemblies involved, a maximum of 3 in actuality as opposed to 193 in the analysis, and the distance between '

assemblies, the two hour estimate is a worst case situation. The actual time to possible cladding 'l' e

rupture would be increased. Cladding damage to the c other assembly in the upender would not occur until ,j 24 days after initial drainage to the seal because of d' the large volume of water surrounding it. ~

c2 I

5.5 FUEL IN REACTOR If the water in the Refueling Area has drained to the ,

level of the refueling seal, the water remaining in .

the reactor will begin to increase in temperature if . . ' . .'

there was no circulation. This will be relieved by ~

the Residual Heat Removal System (RHRS) which is. - S functioning during the refueling process according to - - ~

Technical Specifications (Re ference 3.20) . The' RHRS will remove the heat energy from the core and the Reactor Coolant System by recirculating a minimum of 3000 GPM through the system. Therefore there is no L1 possibility of cladding damage even if no operator action is taken because the RHR System is functioning ,

during any refueling procedure. f The make-up capabilities to the reactor are supplied from two sources. The first is the remaining water in the Refueling Water Storage Tank. This tank will contain over 100,000 gallons of water available for use. An alternative source of make-up comes from the Reactor Sump. Use of this sump would recirculate the '

drained water into the reactor, therefore achieving minimal water losses due to the seal failure.

5.6 FUEL IN SPENT FUEL POOL

' Once the liquid has drained to the level of the refueling cavity seal, another situation may arise.

The liquid in the Spent Fuel Pool will begin to increase in temperature and may begin to boil fuel.

' resulting in the possibility of exposing spent The worst case considered is when a full core load is removed from the reactor 400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> after shutdown.

EDD-7 FORM 1 REV 0 10 SEPT 81

' - Prg3 9 of 13

,i S-C-N300-MSE-285, REV 1 Dato: 12/17/84 u Although the Technical Specifications allow for fuel removal.after 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />, it is not expected that any ~j f .unameding will occur until at least 400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> have n isThis is a result of all other procedures

.o p wa @sakimust take place prior to the actual unloading -1 ofIfuel'during a refueling outage. It would take 4 three hours twenty-three minutes for the water in the Spent Fuel Pool to reach the boiling temperature of .]

212 *F. The water would then boil off at a rate or 'l 52 GPM resulting in the water level to drop at a rate d of 4 3/4 inches per hour. Since the active portion ~

of the fuel assembly is only three inches below the  % ,

level of the refueling seal, tho' fuel will be exposed 1 approximately four hours after the initial drainage 3 occurs (Re ference 3.4) . *J 1

If no operator action was taken, the fuel rods would -

become exposed to the atmosphere. If no credit for any cooling by water or steam is taken after the .

water lavel drops to the active portion of the fuel -

(an extremely conservative assumption) there is a possibility of cladding failure two hours after the active fuel is first ancovered (Reference 3.6) or six , - -

hours after drainage to the seal level. In '

actuality, it would take almost thirty hours to boil -

- ~

off the total volume of liquid. The majority of heat generated from the fuel rods is produced in the central region, which will remain covered with water for fifteen hours. >

h M

The boiling water in the Spent Fuel Pool can be replaced from the Demineralized Water System, Holdup Tanks, Primary Water Tanks and the Refueling Water Storage Tanks, as outlined in the Operating Instructions (Re ference 3.9 and 3.10) . The Demineralized Water System contains two 500,000 gallon tanks with a pumping capability of 650 GPM to the Spent Fuel Pool. There are three 63,500 gallon hold-up tanks connected to a pump that supplies 500 ,

GPM to the Spent Fuel Pool. A third source of make-up water comes from the 250,000 gallon Primary Water Tank and pumps that provide up to 200 GPM of water. Any of these three sources can be made available within 30 minutes. Water can also be.taken from the. 100,000 gallons remaining in the Re fueling Water Storage Tank. This can assure 100 GPM through the Refueling Water Purification Pump given a 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> preparation period to properly align piping. This total make-up water supply will more than replace any water lost from boil off in the Spent Fuel Pool.

EDD-7 FORM 1 REV 0 10 SEPT 81

- - peg 310 of 13 S-C-N300-MSE-285, REV 1 Dato: 12/17/84 0 5.7 CONSEQUENCES OF A DROPPED FUEL ASSEMBLY

+ .v cvm ~ , - h d M notedwin the test section above, we tested a 6 inch c_stgment to a load of 2,250 lbs. without pushing

. " thro 6ghnthe segment and without any permanent deformation. It is-our judgement that the seal can g withstand even greater loads than this. Since the A maximum height that the fuel assembly is allowed to 9 drop is approximately 2 feet (as a result of limits on N the manipulator crane) it is our judgement that the i load drop on a seal from this height will not result 4 in the seal being dislodged from the annulus. 4 i?

To address this concern on a long term basis, we intend on doing a test to demonstrate that the worst d,(

anticipated load drop will not dislodge the seal. p 5.8 FLOW LIMITING DEVICE =

As stated previously there are sufficient design -

differences between our seal and the Connecticut Yankee seal to assure us that the seal failure R -

incident at Salem is not credible. The testing that ' I <

we have performed confirms these statements.. For this . ,

reason it is our belief that flow limiting designs .  :

such as those installed in the Haddam Neck design are not required at Salem.

Although the seal failure is deemed incredible we are, y never the less, in the process of instructing (

operators with a integrated refueling procedure to ~

2 assure that they will take mitigating actions to address a postulated seal failure.

5.9 FAILURE MECHANISMS l The failure mechanisms of overpressurization or loss j of air pressure have been reviewed and we have determined that in our seal design the 3+

overpressurization incident is not credible. Our air ^<

supply line contains a manual regulator and a relief valve l set to 35 lbs. Furthermore, with 'our seal design we have determined that overpressurization will not result in the same type of failure as Haddam Neck.. At Salem the upper half 'of the inflatable' portion of ' the seal is within the refueling cavity and will not balloon out to any significant amount. As the seal is pre ssurized, this portion of the y

EDD-7 FORM 1 REV 0 10 SEPT 81

'S-C-N300-MSE-285, REV 1 Pcg311 of 13 r Dato: 12/17/84 seal will ledge andhave almostvertical will resist full surface movement. contact with the t the lower half is likewise restricted against One side of ,

ballooning out.  ;

+

In compariso~n, the Haddam Neck design results in

~

considerable ballooning of the seal tending to pull 4

the wedge down with little surface contact between the  ?]

M' inflated portion and the cavity to resist the downward vertical force. With respect to the incidence of air d'1' loss, our seal has been designed to provide the necessary sealing capabilities uninflated.  ;

4 5.10 REDUNDANT FEATURES

, [.,

4 As stated previously we have taken the necessary ki actions to mitigate any credible accidents as a result .

of seal failure. Our seal does have redundant sealing .

methods. One is the inflatable portion which inflates in the 1.8 inch wide cavity. The second is the wedge .

on the top of the seal which is held down by brackets. We do not feel there are any credible R

events which could lead to a significant seal failure 1

~

because of the high safety margins that the seal ..

testing has demonstrated.

5.11 RECOMMENDATIONS The following recommendations shall be implemented prior to refueling. -

3

'[

1. .

Inspect valves and2WL3 2WL2, replace. and 2WL221 if necessary the internals og_ I (if installed). @% j These valves are potential drainage paths out ofclosed) these va '

the refueling canal.

2. Keep the removable handwheel attached to the transfer tube valve whenever the valve is epen. ,

i Close the valve when fuel is not being transferred l

t (e.g. afr.or core unload, but prior to reload).

1

3. Manipuist.e only one fuel assembly in the refueling

( cavity so'only one fuel assembly that is inside l

the Containment Building, but outside the core

' could be in the vertical position at any given time. A Fuel Assembly can be in the process of being transferred to the Fuel Transfer Canal while a Fuel Assembly is EDD-7 FORM 1 REV 0 10 SEPT 81

_ _ _ _ _ _ _ _ _ _ _ _ - - - , - -__ _ -._s-_ _ . _ - _ - - , , , , _ , - , - - - -

f Paga 12 of 13 s

S-C-N300-MSE-285, REV 1 Date 12/17/84 in the Manipulator Crane provided that the Fuel j

g. Assembly in the Transfer System is in the ,.

~

gS JkrN[ehorizontal

thyv position. a'

' Y.b$#Rdd Charige Fixture located in the refueling 3 4

' cavity shall not be used for temporay storage of fuel assemblies.

)

5. Prior to flooding the Reactor Cavity, an R

1

" Integrated Procedure "shall be prepared with appropriate personnel properly trained. The Integrated Procedure shall incorporate conditions e j

that indicate a loss of Refueling Cavity water level and the subsequent emergency actions. The  :

S emergency actions shall include instructions to i i place fuel assemblies in .the safest location, -,

closing the Fuel Transfer Tube Isolation Gate 1 valve, establishing flow paths for make-up water to, the Reactor and Spend Fuel Pit. '

6. The air supply to the inflatable Reactor Cavity

' Water Seal shall be regulated to 20 psig , ,

(operating pressurp) and shall include a relief t ,

valve set at 35 psig. -  :

7. Measure the deflection of the top surface of the Refueling Cavity Water Seal as soon as the seal has been installed and inflated. Inform Systems Engineering of the results.

6.0 CONCLUSION

/

SUMMARY

1, 1 1 i

' There are a number of substantial dif ferences between the d l

refueling cavity water seal design used at Connecticut "

i Yankee's Haddam NeckAtand thethat Salem usedStation at the Salem the cavity Nuclearwall Generating Station.

l ledge is beveled to a 20* angle and has been machined and In addition, I

backfilled forming a smooth surface finish. '

l the reactor vessel seal edge has been hand deburred to produce a more effective seal surface. The inflatable seal  ;

used at Salem Station is wider across the wedge portion and is used to' seal the same size area. The seal material is harder than that used in-manufacturing the Haddam Neck. seal i

and will aid in the prevention of. bowing' and be'nding.

Haddam Neck also utilizes a lubricant in seating the seal,

~

/

which is not done at the Salem Station. To increase the l

safety margin at the Salem Station, brackets are placed on top of the Presray seal to further assure a secure closure.

EDD-7 FORM 1 REV 0 10 SEPT 81 i

l

h Pag 3 13 o f 13 S-C-N300-MSE-285, REV 1 Date: 12/17/84 ]

Maintenance procedures at the Salem Station further As a confirm result ,

proper: placement. and utilization of the seal. -

of theinumerous differences, the probability of seal 1 failucejat the Salem Station is considered significantly l'ower than' at Haddam Neck and a gross seal failure is

~

considered" highly unlikely to occur. These conclusions R a 1

have been confirmed through rigorous tests on the seal used ,

at the Salen Station. y Although precautions have been takan to assure the ];

reliability of the refueling cavity water seal at the Salem j Nuclear Generating Station, theThere consequences of ameans are adequate seal of j failure have been evaluated. 4 detecting a seal failure and subsequently preventing fuel

• y failure through existing signals, procedures and Technical Specifications. Implementation of the recommended - -

{'f:

" Integrated Procedure" that addresses a loss of Refueling 5 Cavity water level will further In increase addition, duringthe safety margin extended periods I at the Salem Station. -

of time where transfer, there the Fuel are no Tube Transfer core alterations or fuel isolation valve shall be closed.  :

• e b

.,j s

EDD-7 FORM 1 REV 0 10 SEPT 81

j .

i

, l l

• l 1

4, . ;

i Pneume)^ $S*;'.

i Pneumatic

~

Sea 1

.Q S. x ,.,. ,.

.c uu-a

• ?,

l ,

Q **~ ~~u

~

^

~

scu maa/--

g g e W ,,

I e . . ',

.tg

'~

g I U T,* "9""H if J uy T p$s.

i, -

11

, 88

!  :)

\ 'y L' :.

LI -

.'l l p

f.

1 i

j .

I 1

l Figure 1 - Haddam Neck Refueling Cavity Water Seal I

l l

.I l

a g g erwph  % ] Ja ,.1 , *, gd} I

• g ad e. b a.

S s.

9

\ , - .7. W- +c. c; , s

. m '. . ,

^

6 ..,

e&h

/Q i , .

_ ru 1.. ,

d bN.

i_ . a .2 1 ..

il '

1 ,

' f

, 1 - .n 7".,4  ;- w ma . *

[- -

.*d.. , . ' - D%.,., , 9g ' '

\

, '%%. J.

s. ;s" ' .,-

• • • ' M. ' s -

,,,.,J\ . , . . . .g.e. - N

5. <

p,Ln I I

- 'J L.'WJ g

.6  % p,i

. ~

-- [? -  ;;  ;

L =.. . . .

s

, e .

!:.9. :e . .

M 4=

• ( t& 4sT9 f Vf.A %4.A g gn 6 A\4,ew MO L.A4 4 / b M V 4.M k dh N

[g gg g 1-Re.fu.o.ng C al. ha brww hs g~

--m.-. - -. , , . _ . _ - , - . - , . . . - . _,,m ,- _w . , -.,,. -,c- ,_.-_w,-,...e,.-__,%__, ._,g- . , . . _ . , - _ , , , , , ,

y a - g I

*$ $ ,,[ '

{' - .l-*

> k.?j.

= ,- .

I

- f_

.M y; N. ' ..

• .tp;.,

t; .&7

• 1 _;: i. -

gr . p- L.; '.T~%$. $,:'. f~. . y - .-* g:> .a -

A;.

N. *a .. > ..; ,

s . . .

,n ..

. r ..

.r.- t .A, . . ,,.: -.  ;

.J ., ., e. .

~:-

2 .s .

+ %,, % . af t- q $. w$.a ;j f .

i j f.'.~ .

5.

w'~ .'

~_ ._ .

5+ .

., T i u d "5 - $h Mocw qw,,t

. 4

. r s.

.' r Q~

. 3 I. S D7 -

., .,j t

' b t

.}7 ,

l' - .

. . .4

, g<

. 3 .

. i, >:

. .,' s.. r . .5

'. g: * .-

h : + ~ , 3, y

.. .. . '- p. -

• 4 ., 4- .

.Pc

. ... ,, .,'. r.? .s

. _. ~ FAERIC REINFCAC.CCC, t

. c. 1 *

l. HOSE 3G,"LG .

s .

J.. .j.

- te"RE F = j *

-IS - O.. .

1

' ~

- ~ -

REF

. _ Fa,og q uesn A l . ,

i G,,'

/

1[ QEF -

%W 'k d,, ~

, ~

,Mb ,

,s-...- ~ ... _

g 9 .. . '

9 .9 '"' 4 l g h'].-*g~ ,

2 QEF 8~  ; s. .~g.k '

)'

W.'

.1

. l' 'P .

4 4

. , .i g ,.

P .

i I

of (s REF

'4

'Y I

c 2, -t /2 REF

,v-v ,----m ew,,,--,,,.,,,,,.._--n,,,,,,.e.,,_,,n _n,-- - , - . - , , , - , - , _ . ~ - , - _ _ - - _ - . , , , . - , , . - , _ - , , _ _ _ _ , _ _ _ _ _ - , - - - _ - - - - - - - --

4

.. 40 ,

\ .

. :7::" ~ ) '

~'

'igyg[ _ rzeums 4 l

musemast~cav1Tr warsa snar. Tast #1 s

4 e

?,

e'~6R en [i_

1 NOTE- ' 't a i.

TEST RiCr W As 6 M ~

,y' 7 ' .

INVGRTED(,RS snowg) v.a. wsr i%

. . -o" CcNVENis pac,E l

[

I C 1.852.o5- - *

s. _.

/

r

\/ / /. .

PRsSRRY PR.S 587 RG FUGLIA)G SGAL l

f

< 9.0" >

14T5

....4.

M ,

FIGURE f

'2 CAVITY MATER SEAL TEST 92 i;,y,.??

?.~

2 NOTE'.

W5T Rie W85 7 l

INVER.WL (AS 5%ow4) 1:oA TESTtM&

C.oNVEN)EN C.E

!. < g.so"*,oS - ,

/ .- .

/ ,

w .. n

/ -

/ / .\d/ /w V

e

4. 0 "  ;

h/

/ N PRE 5 RAT

/

p \". -a

?"

i

/

PRS 5 8 5 REF0EuM( SEAL l ~

/s 1 J L FoRLE t4TS

- - - . L 4a- a --4s,__ - ---->--,_-_.,L -

uw. .-awsa - _. ,,_ .., ,,_a _

f "*

e y ',- ~,$,A l

s...

' FIN 4 TNT 92 - MERSURE DNous g 1980 lb b ,

', = ,

3 g

w.,f r -

,..s*r?

• _'I y4 h, t._ j. . .

-' A , s,<,

i

~

• h .

9 4

/ -

=

t O

ar y 20* nEVGL y

/ /

h a

-. y' I

%. v l'Xt y -

N' N

- 5, If h-Form = M 80 43  ;

I l

OTS