ML20238D885

Rev 1 to Criteria for Prevention & Detection of Hydrogen Leaks

ML20238D885
Person / Time
Site:	Peach Bottom
Issue date:	01/09/1987
From:	STEARNS CATALYTIC CORP.
To:
Shared Package
ML20237L734	List: ML20237L732 ML20238D865 ML20238D885 ML20238D890 ML20266J724 ML20266J726
References
NUDOCS 8709110469
Download: ML20238D885 (25)

Text

_ _ _ _ _ _ _ _ _ _ _

e . .

287000045; m r% ,.

M ac'hM9M { h b2) O ')

ScKev Qdocais Gr COM l5M f s . ^_ . . t -

,_"j i

STEABNS CATALYTIC C0ffrRACT NO. 39,775 , ,

PHILADELPHIA ELECTRIC COMPANY PEACH BCTPIOM A'ICMIC POWER STATION HYDROGM WATER CHDUSTRY SYSTm CRITERIA FOR PREVENTION AND DETECTION OF HYDROGm LEAKS Prepared By:

stearns Catalytic Corporation 87091h469g70B240CK pDR O M 277 Philadelphia, Pennsylvania PDR O

January 9, 1987 - Rev. 1 l

2870000452 f-, ,

% STEARNS CATALYTIC CONTRACT NO. 39775 PHILADELPHIA ELECIRIC COMPANY PEACE BCTPICH A'ICMIC POWER STATION HYDROGEN WATER OEMISTRY 1

CRITERIA FUR PREVENTION AND-DE*rECTION T HYDROGEN LEAKS TABLE OF CCNTENTS

1.0 INTRODUCTION

1.1 Purpose of System 1.2 Hydrogen Considerations 2.0 SYSTEM PERFORMANCE 2.1 Present and Future Performance Criteria 2.2 Present and Future Performance Data 7,,,, 3.0 PIPING ARRANGEMENT .

3.1 Hydrogen Distribution System as Designed 3.2 Outside Piping Arrangement Alternatives 4.0 HYDROGEN RELEASES 4.1 Hydrogen System Volume 4.2 HVAC Performance 4.3 Hydrogen Release Characteristics 4.4 Hydrogen Release Ignition Effects 4.3 HVAC Performance I

5.0 LEAK DETECTICE AND PREVENTION f,1 Hydrogen Distributicm System Design Criteria 6.2 Shrouding / Hydrogen )bnitors/ Thermal Monitors 5.3 Excess Flow Check Valves 5.4 Packless Valving

5. 's Pipe Weld Liquid Penetrant Testing 5.6 Helitan Pressure ' Besting 5.7 Alternative Imak Detection and Prevention Methods 5.8 Vent / Purge System and Preventative Maintenance 6.0 10 CFR 50.59 CONSIDERATIONS REFERENCES ATTACHMENT 1 - ANALYSIS T HYDROGEN RELEASE D = .0435 In.

ATTACHMENF 2 - ANALYSIS OF HYDROGEN RELEASE D = .4073 In,

y .

m "c 287000045?

1.0. IlWRODUCTION'

.1.1. Purpose of System l' The Peach Bottom Atomic Power Station, consisting of two (2) Boiling L Water Reactors (BWR) and associated.equipnent, has experienced iIntergranular. Stress - Corrosion Cracking (IGSCC) within each reactor's 1

stainless steel recirculation piping. It has been determined that IGSCC is caused, in part, by radiolytically dissociated oxygen produced'within .i I

n ,

the reactor core.

IGSCC can be reduced or eliminated by suppression of free oxygen within the reactor. This is accomplished by introducing excess free hydrogen into the reactor acre. The Hydrogen Water Chemistry System has been designed to inject quantities of hydrogen into the feedwater systems of

., . each uhitj'determinep by General Electric through plant testing to be -

sufficient for recirculation oxygen suppression.

1.2 Hydrogen Considerations Hydrogen is a colorless, odorless, highly flamable gas. It is nontoxic but may produce suffocation by diluting the concentration of oxygen in air below levels necessary to support life. Concentrations of hydrogen between 4 percent and 75 percent by volume in air will burn when ignited and, under certain conditions, can explode. In addition, hydrogen burns with an almr=t invisible flame and personnel can be injured by the flame because it is difficult visually to detect. The potential for forming and igniting flamable mixtures containing hydrogen may be higher than for h flamable gases because hydrogen readily migrates through small openings and the min 4== ignition energy for flammable hydrogen mixtures is extr eely low. the amount of hydrogen gas necessary to produce oxygen 1

l

^

I (Continued) 20700004R?

1.0 , IfMRODUCTION deficient atmospheres is well within the flanmable range.

'Ihe hazards associated with the use of hydrogen can be controlled by appropriate design and operating procedures'that prevent the formation of combustible fuel-oxidant mixtures and eliminate the potential hazard of k

~

asphyxiation. The PBAPS Hydrogen Water Olemistry System has been designed to provide =W== system integrity, early detection of hydrogen.

leaks, excess flow protection and automatic system shutdown if a failure is detected.

e e

g g ,

g $

_4_

i b_=____.________.

..e E . '*

, .. .?o70000452 2.0 SYSTEM PERPOEDOWCE

, . 2.1Present and Future Performance Criteria noduction'of dissolved oxygen concentrations within the reactor is accomplished on two (2) levels. We lower level involves the

" suppression" of oxygen within the reactor recirculation piping only, dille the higher level produces " suppression" of oxygen in the reactor oore as well as in the recirculation piping.

' h e_ Hydrogen Water Chemistry System has been designed to initially.

grovide sufficient hydrogen to suppress oxygen levels within the recirculation piping only. Design consideration for subsequent " full suppression" flowrates of hydrogen has only been given to permanently

~'

installed equipnent, such as, piping., Transmitters and flow controllers are sized for recirculation piping suppression only.

- % e Hydrogen Water Ciamistry System has been designed with redundant flow control trains for each unit and single branch injection legs'to each of the three (3) reactor feedwater pumps per unit. Each branch injection j leg is capable of 100 percent full suppression flow. Wis capability has been designed into the system to ensure operating flexibility during maintenance or repair of pump branch flow control equipnent. Wis configuration is also required to meet geometric constraints for f i

effectively injecting hydrogen into the reactor discovered during the  !

General Electric mini-test.

I l'

l l.

L____________

Po7000045?

2.0 SYST!!N PERFORMANCE (Continued) 2.2 Present'and Future' Performance Data

% e initial design flowrate of hydrogen for reactor recirculation piping-suppression only is' sixty (60) standard cubic feet per minute (SCEE) per unit. The flowrate of hydrogen required for " full suppression" will be approximately 200 SCFM per unit. %e hydrogen pressure for each flowrate will be 1000 PSIG downstream of the gaseous storage tube dis.harge r 5xessure reduction station.

Additionally, the system will be capable of providing fifteen (15) SCPM for generator stator cooling. This feature will allow Philadelphia Electric Otznpany to discontinue use of the existing hydrogen gaseous storage tubes. located adjacent to the south wall of the turbine building:

at a convedent , future clate.

+ - ,

Hydrogen system flow control devices such as flow control valves, excess flow check valves and flow meters will be specified to operate under the These reduced capacity condition for recirculation piping suppression.

instruments and valves will require replacement'or modification at a later date to act-----Ste hydrogen flowrates associated with full suppression.

i l

h E

L1' f

2870000452 ' ia l .. .*- 1 1

l 3.0 PIPING ARRANGDENT .j j

3.1 Hydrogen System as Designed l Each unit'contains a main flow control station with redundant trains.

% e Unit 2 main flow control station is located on the north wall of the  ;

Jfeedwater pump 2C turbine-driver room.- The branch flow control stations )

i i

for each of the three (3) Unit 2 feedwater pumps are located overhead on -

I the east wall of each of the three (3) feedwater pump turbine-driver ]

I roczns.

The Unit 3 control system is similarly arranged. The branch flow control stations are located overhead along the east wall of each of the three feedwater punp turbine-driver rocras. We main flow control station'for Unit 3 total flow control is located on the west wall near the hydrogen

- - s'ystem.tu ^ine building penet'ation.

r '

This arrangement results in approximately 1,600 feet of 1-inch and 3/4-inch distribution piping within the turbine building, including the generator stator cooling back-up hydrogen supply line. Including the valving at the injection points for each feedwater pump, the system valves and instruments are grouped into seven major stations per unit. ,

l Except for check valves, which are supplied with welded bonnets, there are no interior valves or instruments located outside of these seven stations.

I

-i

2870000452-l- '

3.0~ PIPyt? EtRANGDG!NP (Continued) 3,2 - Outside Piping Arrangement Alternatives

' several alternatives were considered for routing significant portions of Such arrangements-the hydrogen piping outside of the turbine building.

as penetrating the injection lines through the west wall of the building d

and dropping the lines through the turbine building roof were considered. It was determined that although a-slight advantage may be gained by locating the valves and instrtsnents outside, the amount of

. piping running within the turbine building would not be significantly reduced. Furthermore, to achieve the same level of safety outdoors,'as has been established inside, the valve and instrument stations would require either a quarantined area or a remote location-that would render

. maintenance and. surveillance of the valves ard instruments difficult at ,

best.

_e_

2870000457

~

i _4.0' Hronoaan an.easss 4.1 Hydrogen System Volume To gain'a perspective of the potential leakage concern, it is necessary to consider the quantity of free hy& vge- in the turbine building at any given time. Based upon the detailed piping configuration, the total clear voltane of the system is approximately 4.0 cubic feet, excluding

.normally isolated vent piping. At the. normal operating pressure of 1000 PSIG, this translates to approximately 335 standard cubic feet of hydrogen, including a conservative allowance for valves and fittings, hththesystemfull. I 4.2 HVAC Performance Due to the difficulties of determining hyd,rogen concentrations within , ,

specific sections of an otherwise open building, an approach has been taken which considers the steady state hydrogen concentration in that ~

portion of the turbine building containing the major valve stations.

'Ihis approach is considered realistic when consideration is'given to the locations of the potential leak sources within the system, which are essentially limited to the valve stations.

'Ihe total clear voltane of the areas bounded by turbine building Coltunns 23, 36, M and J is calculated to be 350,000 cubic feet between M evations 165 and 195. The feedwater heater bays have been excluded fran this voltane due to the degree of separation from the hydrogen system.

_9

_ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ - _ n

P8'0000452..

4.0" HfDROGDI RELEASES (Continued)'

A review of the HVAC details for the area reveals 16,200 CFM of air is supplied to the area, with an equal quantity exhausted frcm the space.

Using the =v4== postulated leak rate of 90 Scim, a maximum steady state hydrogen concentration of 0.560 percent is calculated, which is significantly below the lower flamable limit of four percent and far below the concentrations required to produce oxygen deficient atmospheres..

%e hydrogen leak rate required to obtain a steady state cx>ncentration of

~

four percent is calculated to be in excess of 600 SCEN. Wis is nearly

.700 percent of the excess flow check valve setpoint for each unit, and 300 percent of the cannon hydrogen supply header excess flow check valve

. , 'setpoirit. For. a completie discussiod of excess flow protection, "see Section 5.3 of this report.

'4.3 'Hydrerlen Releases Characteristics h arisessment of p)tential hydrogen release characteristics was made using calculation techniques which model the piping system as a vessel, holes as orifices, and the pitane as a jet. These techniques are .I consistent with those used in various safety analyses used in other portions of the generic hydrogen supply system safety analyses done by l APCI (Reference 1). These models are described in detail in Reference 2.

1 i

. 2870000452 4.0 HYDROGEN RELINES amall Release Rates.- Releases from hole sizes of greater than 0.0435 inches in diameter will be isolated quickly by the excess flow check valves. For this reason, a plume jet characterization calculation was done for this size hole asstaning a continuous leak. %e output is Attachment 1. . h e hydrogen release rate of 90 scfm is very small l

omnpared to area air turnover rates. W erefore no area buildup of hydrogen is expected from such a release. Unless the jet plume strikes an ignition source, the hydrogen will be simply dispersed and exhausted without effeet. Ignition sources in the vicinity of the hydrogen lines are mininal.

Large Release Rates - Releases from pipe breaks sufficient to actuate excess flow protection v419es t may still result in the release of pipe hydrogen contents downstream of these valves. We total system inventory inside of the isolated system is 335 standard cubic feet. We total contents can be released very rapidly, depending upon hole size. We i

more rapidly the hydrogen is released, the greater the portion which is -1 within flannable or detonable limits.

he jet model of Reference 2 is for a continuous release. It has been modified to allow for the effects of decaying pressure in the piping )

I system. Attachment 1 traces the pressure if this limiting unisolated j I

break had been isolated.

Reference 2 indicates that, regardless of the hole size, the mass and i

voltane ratio of gas within detonable and flanmable concentration lirdts )

l remains constant. Reference 2 does not provide the ratio of gas within I l

the flannable concentration limits to total hydrogen.

l I

i

_ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ . _ . _ _ _ _ _ ._ . _ _ _ ._)

m. .,

, --- 2870000457.

p ..

4.0 HYDROGEN RELA'ASES -

To assess theacret' case dispersion, a hole size was chosen which results

~

c :in a predicted weight within flamable, limits equal to the total. .

available gas. ~ W is hole size is 0.4073 inches in' diameter. With 335 standard cubic feet (1.75 lbs) in the flamable range, this would lead to 10.6 standard cubic feet of hydrogen (0.055 lbs) in the detonable concentration range. Attachment 2 is the output for this case.

'For larger hole sizes, the plume formation will probably be aborted by

. depletion of the hydrogen supply. Nonetheless, the releases will be

~

similary turbulent, and the above ratios of detonable to flamable hydrogen is expected'to continue to be a reasonable approximation.

4.4 Hydrogen Release Ignition Effects

• 5 In order fok the plume td ignite, it must etncounter an ignition source, such as an open flame, a spark, or a surface'in excess of 900 F.

Ignition sources in the vicinity of the hydrogen lines are minimal. 1 Nonetheless such an ignition cannot be absolutely ruled out in a normal  !

1 i

power plant environment. Therefore, the potential impact of such an j ignition are considered.

In general,.because of the possibility of a short duration fire or small explosion, it would be unacceptable to route hydrogen supply piping in enclosed spaces containing safety related equipnent. %is criterion is met for the PBAPS hydrogen supply system, where all associated piping is in the turbine te41r14ng.

fi

- . ,1 .  ;

1

+ " 2870000452 l 4.0 ' HYDROGEN RELEASES (Continued) ]

I small Release Rates - In the event that this small release plume should ui s

I strike an ignition source, the flame would take the form of the flamable:

cloud described in Attachment 1, i.e., up to 6 feet in length and.about 5- l cubic feet in volume. It is expected that combustibles in the very near i

R vicinity could be' ignited, and fire suppression system actuation may result. .It'is not expected that this limited fire would have any impact .,

on safety related equipment.

%e ceametry of walls around the. hydrogen piping are such that no significant confinement of the release results.. No detonation of even the extremely small amount of hydrogen in the detonable concentration range would be expected.

Iarge Release Rates- As discussed above, the worst case release of hydrogen is assumed to be 1.75 lbs of hydrogen in the flamable concentration range, and 0.055 lbs of hydrogen in the detonable concentration range. The areas through which the hydrogen piping is routpd do not provide much confinement and such a release is expected to be r'apidly dispersed to below flamable limits.

1 Generally, to achieve detonation, the hydrogen should be confined in a l high L/D geometry, such as that provided by a pipe. The confinement geoletry in the turbine building can be described as minimal. Tbtal I

disnersion, even in local areas, generally would result in concentration halfar flan =nable limits. For this reason, only a deflagration would be 5

expicted in the event of pi ne ignition.

i

! i 4

t l ,

h '

k l l

s, ,

c ..

2870000452 4.0 HYDROGEN RELEASES (Continued)

All areas have at least one wall that does not extend to the ceiling thus L. ,

providing a'large open venting area for any pressure buidup. Because of-this, any deflagration would be expected to result in a short fire, possible actuation of. fire suppression systems, and no structural damage effects. Any damage would be confined to the turbine building and in the local vicinity of the fire and result principally from direct heat flux.

s O 0 $ g 4

4 g 9

i

2870000452 5.0 LEAK DETECTION AND PREVENTION 5.1 Hydrogen Distribution System Design Criteria

%e Peach Bottom Hydrogen Water Chemistry System hydrogen distribution l system has been designed and configured within the turbine building to.

minimize the potential for a system leak using a canbination of material and ev= = nt quality, system integrity testing, and normal maintenance and observation of the system. We system piping has been arranged in such a manner to yield an absolute miniatan of potential leak points, and includes various leak detection and minimization design features which will be discussed below.

5.2 Shrouding / Hydrogen Monitors / Thermal Monitors 1

In determining the **order of magnitude of potential leak rates (see '

• Section 4.2), it was concluded that hydrogen leaks in open areas would l not produce the levels necessary to activate a hydrogen area monitor.

Furthermore, it has been concluded that the plume direction would be too unpredictable to ensure contact with a closely-located hydrogen monitor, thus creating further argtsnent for lack of detection.

Since they provide the highest potential for developing leaks, all valves, instruments and flanged connections have been grouped into seven stations for each unit. Each station will be shrouded, with a hydrogen monitor installed at the top to ensure early detection of a valve or instrunent leak. Each monitor will be wired into a local panel which will provide indication as to which monitor (s) is in alarm. ne main control panel will be wired with a single alarm indicating only that a i hydrogen monitor has been activated. Upon leak detection, the system is automatically shut down.

g ,

" ' 2870000452 5.0 IaK DETELTION AND PREVDFTION_ (Continued)

Special precautions have been taken to eliminate sources of ignition I

within the shrouds. Valves and instruments are explosion proof and conduit runs will be sealed to prevent hydrogen migration through the

' conduit. The autoignition temperature of hydrogen is 932 F so the potential for autoignition is essentially non-existent. The shroud / hydrogen detector approach is designed to provide hydrogen leak detection and system isolation before the lower flammability limit is reached. However, as an added safety feature, a temperature monitoring I

system will also be included to provide detection of an ignited hydrogen leak which is not detected by the hydrogen monitors. A temperature switch will be located near the top of each shroud. This switch will l.- .

provideanalaxmsignalto'themaincontrolpanel'abdwillinitiate' automatic system shutdown when activated.

Except for the shroead stations, hydrogen nonitoring is not included at any other locations along the pipe route. This decision is based on a design philosophy which incorporates numerous features to provide a leak-tight, essentially all-welded piping system with appropriate quality assurance and testing as discussed in subsequent sectiers of this report.  ;

Additional protection is also provided by initiating system shutdown for low hydrogen injection gressure. 'Ihis would occur if the excess flow check valves failed to isolate the system in the case of a major pipe failure.

i

5.0 ' LEAK DEFECFIN AND PREVENTION - (Continued) 5.3 Excess Flow Protection

%e Hydrogen Distribution System is equipped with excess flow check valves located outdoors in the cannon supply header and indoors on each unit's distribution piping just after the Unit 2/3 tee. Each of these valves will be set for 150 percent of the normal flowrate passing through it. . Each unit's excess flow valve will initially be set for 90 SCFM.

Se e supply baaaar excess flow check valve will be set for 200 SCPM, or approximately 150 percent of the two unit hydrogen flow of 120 SCEM plus 15 SCEM for standby generator station cooling.

Functionally, the excess flow check valves serve to isolate the hydrogen distribution system if a hydrogen leak occurs. At full reactor power, a

~

hpdrogen leak' of 30 SCFM will*be adequate td shut the valve hth '60 $iCFM normal full power hydrogen flow. As power level is decreased, the hydrogen leak rate required to isolate increases. For example, at 20 percent reactor powe.r, the recirculation piping suppression hydrogen flowrate is approximately four (4) SCEM. A hydrogen leak rate of 86 SCFM would therefore be required to isolate the system.

Note that the calculated leak rate for a 0.045" diameter hole is 90 SCPM (see 4.2). It is therefore reasonable to expect that the excess flow check valves will provide system isolation for essentially all piping }

failures.

l l l

1 l

I i

4 .

28700004RP 5.0 IDX D=TirrION AND PRWElfrION -(Continued) 5.4 'Packless Valving All hydrogen service valves have been specified as zero-leakage, packless, socket-veld valves. h valves have either a diaphragm or bellows-type seal for primary sealing. Tn ensure gross leakage does not occur due to failure of the primary element, a back up packing arrangement is included.

5.5 Hyd % n Distribution System Pipe Weld Liquid Penetrant Testing Ib minimize the potential for uncontrolled leakage through any portion of the stainless steel hydrogen distributico system, all rdping welds will j

be liquid penetrant tested. This quality esserance measure, coupled with the inherently high degradation resistance qualities of stainless steel, provides a high degree of certainty that leaks will not occur within the distribution system piping.

5.6 Helitsn Pressure Testing All piping and piping ccanponents will be subjected to belitan pressure testing in accordance with the requirements of ANSI B31.1 for gas service piping. With a systm mari== pressure of 1200 PSIG, ANSI B31.1 requires pressure testing to at least 1.2 times 1200 PSIG, with a mavi== of 1.5 l

i times 1200 PSIG. 1 I

i i

1 I

_ - - - ---- _-------- i

2870000452

• J. LEAK DETIrTION AND PREVDirION (Continued)

Helium has been selected for the pressure test medium due to its inherent I

l safety characteristics as an inert gas, and due to its : lose molecular similarity to hydrogen.

5.7 Alternative Isak Detection and Prevention Methods Various alternatives have been considered for the hydrogen distribution 1

system and, for reasons outlined below, discounted. Of major significance is the routing of the distribution system within the turbine building in lieu of outside. As briefly discussed in Section 3.2, an

- outside arrangement would require quantantined areas to ensure no ignition source could be imposed in the vicinity of potential leak sources such as valves and instruments.

. . Additionally, it was considered that leak ' revention p through aggressive *

• mai:;tenance and nonitoring would be considerably nore difficult with the piping located outside. And finally, an evaluation of arranging the hydrogen distribution sy;cem from an entering location at the turbine building roof indicated that not only would there still be significant quantities of piping and instruments located within the turbine building, but physical leak nonitoring throughout the entire system would be imp:>ssible. A review of the piping iscxnetrics for the present system layout within the turbine building reveals that leak surveillance with prtable detection equipnent is possible for a 100 percent of the hydrogen distribution system.

U

, 287000045.2 i

• - s.

..L ,

I-l.

5.0 LEAK DETECTION AND PREVDirION , - (Continued) )\ a T

q

]

i .

Another piping alternative not implemented within the Peetib Bottom j s

Hydrogen Water Chemistry System hydrogen distribution system.is the

. installation of guard piping. .After studying the use of guard or sleeve piping for the system, its was discarded for the following reasons:

y 1

1) Virtually all interior hydrogen distribution piping is run overhdadi 3

'T or shrouded. Therefore the use of guard pipe for protection is not justified.

} .

2) % e use of guard pipe for containment of hydrogen leaks would require

~i a large number of hydrogen detectors in order to 1&mtify leak j l

locations in the primary piping.

s l

3) h design and installation of a ampletely vented guard pipe system j would be expensive and would not' sign'ificantly improve systerit reliability or safety.  !

4) The potential impact of hydrogen ignition has been quantif ed (Section 4.4) and found to be acceptable within the context of 10 CFR  !

50.59 (Section 6.0).

l h turbine building hydrogen concentration calculations, discussed in l

Section 4.2, reveal that overall potential hydrogen concentrations resulting from a leak within the turbine building are too low for hydrogen monitors to provide any effectiveness when lodatstat ceiling height below the elevation 195 slab. Wey have, therefore, not been I

included in the design schee for Peach Bottom.

e

'\s

m, *

$m, jfr,

,, ,o i .I' 2870000452-5.0 LEAK DETECTIG4 AND PREVENTION (Continued) 5.8 Vent / Purge System and Preventative Maintenance A significant safety' feature designed into the Hydrogen Distribution g

.s Syntam is a venting and purging system which allows nitrogen purging of a

f rll or part of the system located within the turbine building.

%e vent / purge system coraists of six purge connections and five vent w u w tions per unit, which allow full unit hydrogen distribution system purgebr indinidual ~ station purge for maintenance or repair. We vent pi g is specifind of equivalent quality and will receive the sans ge! ope-ational testing as the hydrogen distribution piping. The vent-piping is routed to a common riser terminating at the turbine buihling i,

n ,

roof with a freeze protected flame arrester. Eachhiithasaseparate ,

. . . 3 vent / purge system. l A preventive maintenarice and - itoring program is recomended to ensure a

continued safe operation of the hydrogen system. A system walkdown with portable hydrogen detection equipreent should be performed monthly. At this time, each permanent hydrogen monitor should be inspected in acccedance with the manufacturer's directions. Since all hydrogen piping within the turbine building has been designed to be readily excessible, this inspection should not become overly time-consuming.

Valves should be repaired only in the event of a leak. Preventative maintenance to a non-leaking valve is not rir- - =- W. When tearing a valve dow'4, however, manufacturer's proceduras should be followed.

L t

.21 I

l. ,i L . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . _ _ _ 'l

l- >l ,

2870000452 6.0 1,0 CPR 50.59 (DNSIDERATIONS Any accidental release of hydrogen associated with isolated supply piping

.will be rapidly dispersed.. Because of some minor damage potential associated with such a release, no piping will be routed in safety related struevtres or areas with safety related equipnent. Any damage

[

l caused by such a release would be local and will not impact integrity of any PBAPS structures.

Because the postulated hydrogen releases are very unlikely and cannot inpact eafety related equipnent function, the probability or consequences of accidents analyzed in the FSAR are not increased. Since the impa.ct of the postulated hydrogen releases has no radiological impact, no new accident is created. ,' mis event has no impact on any technical a -

specification, or bases. Therefore no unreviewed safety questions exist, per 10 CPR 50.59.

+

i

. .. sy

^

L 3 . ,: 3,$ >

2870000452

s. .* ',

,_s s .

., @y / Tlf ,l t i '  ;#

~

REFERDICEg ^t : t

1. EPRI-4P-4500-SR-LD, " Guidelines for Permanent BWR Hydrogen Water Chemistry Installations", March 1986, by BWR Owners Group for IGSCC l

Research, Hydrogen Installation.Si*v = m4ttee. ,

l

,y >

o

2. Camilli, L.L.; Linney, R. E.; & Doelp, L. C., " Liquid Hy h ap n Storage System -- Hazardaus consequence Analysis', Air ProduNs and Chemicals, 4

Inc., October 1, 1985.

1 . i

/

f

• e

• 4 8

• e l

-l 1

1 i

I l

l l

1 1

J i

..l)

i MTACRET 1 2070000452 i ANALYSIS OF RELEASE OF HYDROGEN FROM 1000 PSIG SOURCE INPUTTED HOLE DIAMETER (inches) = 4.350E-002 INITIAL HYDROGEN FLOW RATE (1bs/sec) =,7.831E-003 PIPE DETONABLE FLAMMABLE DETONABLE FLAMMABLE FARTHEST REACH TIME PRESSURE CONTENT CONTENT VOLUME VOLUME FLAMMABLE MIXT (cec) (osia) (pounds) (pounds) (cu. ft.) (cu. ft.) (feet) 0.00 1006 6.720E-005 2.133E-003 4.221E-002 5.151E+000 5.94E+000 20.00 919 5.874E-005 1.864E-003 3.690E-002 4.503E+000 5.68E+000 40.00 840 5.134E-005 1.630E-003 3.225E-002 3.936E+000 5.43E+000 60.00 768 4.488E-005 1.424E-003 2.819E-002 3.440E+000 5.19E+000 80.00 702 3.923E-005 1.245E-003 2.464E-002 3.007E+000 4.96E+000 103.00 642 3.429E-005 1.088E-003 2.154E-002 2.628E+000 4.74E+000 120.00 586 2.997E-005 9.511E-004 1.882E-002 2.297E+000 4.54E+000 140.00 536 2,619E-005 8.313E-004 1.645E-002 2.008E+000 4.34E+000 160.00 490 2.289E-005 7.265E-004 1.438E-002 1.755E+000 4.15E+000 180.00 448 2.001E-005 6.350E-004 1.257E-002 1.534E+000 3.97E*000 200.00 409 1.749E-005 5.550E-004 1.098E-002 1.340E+000 3.79E+000 220.00 374 1.52BE"00L 4.850E-004 9.600E-003 1.171E+000 3.62E+000 240.00 342 1.336E-005 4.239E-004 8.390E-003 1.024E+000 3.47E+000 260.,00 ,

312 1.167E-0.05 3.70.4E-004 7 331E-003 8.946E-001

. 3.31Et000 2,80.00 286 1.020E-005 3.237E-004 6. 406E-O'03 7.' 817 E-001 3.17E+0Q0 300.00 261 8.91!E-006 2.828E-004 5.598E-003 6.831E-001 3.03E+000 320.00 238 7.786E-006 2.471E-004 4.891E-003 5.968E-001 2.89E+000 ,

340.00 218 6.802E-006 2.159E-004 4.273E-003 5.214E-001 2.77E+000 360.00 199 5.942E-006 1.886E-004 3.733E-003 4.555E-001 2.65E+000 '

380.00 182 5.190E-006 1.647E-004 3.260E-003 3.978E-001 2.53E+000 400.00 166 4.533E-006 1.439E-004 2.847E-003 3.475E-001 2.42E+000 420.00 152 3.958E-006 1.256E-004 2.486E-003 3.034E-001 2.31E+000 440.00 139 3.456E-006 1.097E-004 2.171E-003 2.649E-001 2.21E+000 460.00 127 3.016E-006 9.572E-005- 1.895E-003 2.312E-001 2.11E+000 480.00 116 2.632E-006 8.353E-005 1.653E-003 '2.017E-001 2.02E+000 500.00 106 2.296E-006 7.287E-005 1.442E-003 1.760E-001 1.93E+000 520.00 97 2.002E-006 6.354E-005 1.258E-003 1.535E-001 1.84E+000 340.00 89 1.745E-006 5.539E-005 1.096E-003 1.338E-001 1.76E+000 560.00 81 1.521E-006 4.826E-005 9.552E-004 1.166E-001 1.68E+000 580.00 74 1.324E-006 4.202E-005 8.317E-004 1.015E-001 1.60E+000 600.00 68 1.152E-006 3.657E-005 7.238E-004 8.832E-002 1.53E+000 620.00 62 1.002E-006 3.180E-005 6.295E-004 7.681E-002 1.46E+000 640.00 57 8.708E-007 2.764E-005 5.470E-004 6.675E-002 1.39E+000 660.00 52 7.560E-007 2.399E-005 4.749E-004 5.795E-002 1.33E+000 680.00 48 6.55BE-007 2.081E-005 4.119E-004 5.027E-002 1.27E+000 700.00 44 5.682E-007 1.803E-005 3.569E-004 4.356E-002 1.21E+000 720.00 40 4.919E-007 1.561E-005 3.090E-004 3.770E-002 1.15E+000 740.00 37 4.253E-007 1.350E-005 2.672E-004 3.260E-002 1.10E+000 760.00 34 3.673E-007 1.166E-005 2.308E-004 2.816E-002 1.05E+000 l

4

• ,. 9; ,

287000045?-

T .

^ ATTACHMENT 2

" ANALYSIS OF' RELEASE OF HYDROGEN FROM 1000 PS1G SOURCE

,1NPUTTED HOLE DIAMETER ' (inches). = 4.073E-001

INITIAL HYDROGEN' FLOW' RATE (1bs/sec) = 6.865E-001 PIPE- DETONABLE- FLAMMABLE DETONABLE FLAMMABLE FARTHEST REACH O TIME ~ PRESSURE ' CONTENT. CONTENT: . VOLUME VOLUME FLAMMABLE MIXTUR (occ) (psia) (pounds) (pounds) (cu. ft.) (cu. ft.) -(feet)

.O.90- 1985 - 5. 516E--OS2 1.751E+000 3.465E+001 4.228E+003 5.56E+001 S.25. 911 4.760E-002 ~.511E+000 1 2.990E+001 3.64BE+003 5.29E+001 C. 50' '825 4,187E-OS2 1.303E+000 2.580E+001 3.148E+003 0.75 748 5.04E+001 3.543E-002 1.125E+000 2.226E+001 2.716E+003. 4.80E+001 1.90- 677 3.057E-OS2 9.703E-001 1.920E+001 2.343E+003 4.57E+001

'1,25 61A 2.638E-002 8.371E-001 1.657E+001 2.022E+003 4.35E+001 1.50 556 2.276E-002- 7.223E-001 1.430E+001 1.744E+003 1.75 504 ,1.963E-002 4.14E+001 6.231E-OO1- 1.233E+001 1.505E+003 3.94E+001 2.00' 457 1.694E-OBE. 5.376E-001 1.064E+001 1.29BE+003 3.75E+001 E. 25 - '414 1.461E-002 4.638E-001 9.*180E+000 1.120E+003 3.57E+001

-2.50 375 1.261E-OS2 4.001E-001 7.919E+000 9.663E+002 3.40E+001 2.75 340 1.087E-002- 3.451E-OO1 6.831E+0E0 8.336E+002 3.24E+001 L 3. 00 308- 9,381E-003 2,977E-001,5.893E+040 7.191E+002

..= ,3,25 279. 3.0BE+001 8 091E--803

• 2{56BE-001 ' 5. 083E+000 '6.202E+002 3,50 2.93E+001 253 6,979E-003 2.215E-001 4,384E+000 5.349E+002 2.79E+001 3.75 229 6,018E-003 j 1,910E-001 3.781E+000 4.613E+002 2.66E+001 4.00~ 207 5.190E-003 1,647E-001 3.260E+000 3,978E+002 2.53E+001 {-

4.25 188 4.475E-003- 1.420E-001 2.811E+000 3.430E+002 2.41E+001 4.50 170 3.857E-003 1.224E-001 2.423E+000 2.957E+002 2.29E+001

4.75 154 3.325E-003 1.055E-001 2.OBSE+000 2.548E+002 2.18E+001

5. CO 140 2.865E-003 9.092E-002 1.800E+000 2.196E+002 2.07E+001 5.25 127 2.46BE-003 7.833E-002 1.550E+000 1.892E+002 1.97E+001 5.50: 115 2.125E-003 6.746E-OS2 1.335E+000 1.629E+002 1.88E+001 5.75 104 1.830E-003 5.807E-002 1.149E+000 1.403E+002 1.79E+001

6. $6 94 1.575E-003 4.997E-002 9.891E-001 1.207E+002 1.70E+001 6.25 86 1.354E-003 4.298E-002 8.507E-001 1.03BE+002 1.62E+001 6.50 78 1.164E-003 3.694E-002 7.312E-001 8.922E+001 1.54E+001

'6.75 70 9.998E-004 3.173E-002 6.281E-001

-7.00 64 7.664E+001 1.46E+001-8.581E-004 2.723E-OS2 5.390E-001 6.57BE+001 1.39E+001

'7.25 58~ 7.358E-004 2.335E-002 4.622E-001 5.640E+001 1.32E+001-

.7.50 53_ 6.303E-904 2.000E-OS2 3.959E-001 4.831E+001 7.75 48 1.25E+001 5.393E-004 1.71EE-002 3.388E-001 4.134E+001 1.19E+001 C. 60 44 4.609E-004 1.463E-002 2.895E-001 3.533E+001' 1.13E+001

' - '8.25 40 3.934E-004 1.248E-002 2.471E-001 3.015E+001 1.07E+001

'O.50 36 3.353E-004 1.064E-OS2 2.196E-001 2.570E+001 1.01E+001 8.75 33 2.855E-004 9.060E-003 1.793E-001 2.188E+001 9.62E+000 e

- , . - _ - . - _ - _ - - - - - - - -- - - J