ML20249A312

Proposed Tech Specs Re SLCRS Bypass Leakage (Plar 3-98-5)

ML20249A312
Person / Time
Site:	Millstone
Issue date:	06/06/1998
From:	NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20249A309	List: B17276, Application for Amend to License NPF-49,by Incorporating Attached Proposed Rev Into Chapters 6,9 & 15 of Millstone Unit 3 FSAR ML20249A312
References
NUDOCS 9806160296
Download: ML20249A312 (45)

Text

[

Docket No. 50-423 817276 i

Millstone Nuclear Power Station, Unit No. 3 Proposed License Amendment Request SLCRS Bypass Leakage (PLAR 3-98-5)

Marked Up Pages i

I June 1998 l

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U.S. Nuclxr R:gulatory Commission B17276\\ Attachment 2\\Page 1 MARKUP OF PROPOSED REVISION Refer to the attached markup of the proposed revision to the Final Safety Analysis Report (FSAR). The attached markup reflects the currently issued version of the FSAR.

The following FSAR changes are included in the attached markup.

FSAR Section 6.4 - revised to include a description of the manual actions required to trip the NNS fans and time requirements for control room ventilation realignment FSAR Section 9.4.1 - revised to include a description of the manual actions required to trip the NNS fans and time requirements for control room ventilation realignment FSAR Section 15 - revised to include the inputs assumptions and results of the new LOCA/ Control Rod Ejection accidents i

-)00 MNPS-3 FSAR geg f

. Outdoor air is supplied to the control room envelope at afrate of 1,450 cfm end S ' 'd

(

eenetont during normal plant operation. Mechanical exhaust is provided from the control.

room toilet and kitchenette exhaust fan at a rate of 595 cfm. Thus, a positive pressure is maintained during normal operation.

When the control room must be isolated in an emergency (LOCA or high radiation alarm l

55) 3 from intake monitors) or by manual actuation, the outdoor air and the exhaust air isolation butterfly valves close. The air-conditioning units serving the control room envelope continue operating -without cutdoor air to maintain required humidity and temperature.

Following a Control Building isolation (CBI), the control room pressure envelope is pressurized from one of two banks of air storage tanks to 1/8 inch water gage pressure differential. Although the differential pressure may fluctuate, the control room pressure (g.4 envelope maintains a positive Dressure relative to surrounding area /After one hour, the

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(~ isolation valves can be opened to divert outside air through the control room emergency -

(ventilation filterdln the event that inlet isolation valves fail to operi, operators are able to lowe.T b manually open those valves using the rnanual jack screw operator. Since the location of these valves is within the control room habitability zone and the valves are designed for M NI manual manipulation, control room personnel are able to open these valves within c.ie hourg nM

' following control room isolation.

The pressurization system for the control building envelope has two banks of air tanks with its associated piping, instrumentation, and controls. Each bank is of 100-percent capacity and in case of failure of one bank, the other redundant bank starts automatica!!y.

The calculated ventilation filter flow rate is 1,225 cfm (clean) and 1,000 cfm (dirty). The i

actual flow rate is in accordance with performance testing requirements which ensures that s5 U

filter flow rates are maintained within an acceptable tolerance of design flow. The recirculation air rate from the control room to either filter return can be varied between O to 915cfm.

Redundant Seismic Category I radiation monitors are located at the outdoor air intake. If high radiation is detected in the intake air stream, the CBlVs are automatically closed. A smoke detector is also provided at the air intake and,if smoke is detected, the alarm is annunciated in the control room for operator action. De radiation monitor high alarm hfl setting is discussed in the Technical Specifications.

A 1-hour air supply is provided from the control room area pressurizing air storage tanks.

oih 6.4.4 Design Evaluation The control room air conditioning system maintains a suitable environment for personnel and equipment during normal and emergency conditions. Components of the-air-conditioning and chilled water systems are designed to Category I criteria and are enclosed in a Category I control building with the exception of the air conditioning unit electric heaters which are Seismic Category 11. Electric heat is not required during design basis events.

Allintake and exhaust openings are tornado missile protected. Outside air is not used for t D iour af ter an accident. Outdoor air is filtered by one of the emergency ventilation i

filter assemblies.

l

% m.me M nne.

es w a G.4-7 December 1997 l

18-mp 5-g oo j

INSERT A After one hour, realignment of the control room ventilation system from the pressurization mode to the filtration / recirculation mode of operation can be gI initiated in the event of a LOCA, p b t; spenb;; the b';t L;;;;er, set.ee, operator action is credited to secure selected Main Steam Valve House, Auxiliary l

Building and Emergency Safeguards Features Building exhaust fans, specifically fans 3HW-FN1A&1B,3HVR-FNS&7 and 3HVQ-FN2 are secured. This action is completed witt.in 20 minutes during which time the control room will depressurize i

to ambient pressure. The isolation valves are h opened, to divert outside air through the control room emergency ventilation filter.

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l MNPS-3 FSAR h - /-t /g.j o g i

Ir..s3) 7.

Each battery room has an independent exhaust fan and associated ductwork. Air 4/W to these areas is drawn in from adjacent switchgear areas through louvers, filters, and grills. To make up for the battery room exhaust and to provide ventilation air j

in the switchgear areas, independent supply ducts with an axial fan rated at 1500 cim, electric heating coils, and prefilters are provided.

The control room emergency ventilation filtration and pressurization system consists of redundant pressurization air stcrage tanks and two redundant emergency air filtration units.

6 The air pressurization system operates durina the first hour of an accidentjAfter 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, 9

door air can be introduced into tne system through the emergenc/ ventilation filtration l

unit.

Each of the air-conditioning units is supplied with chilled water by the control building chilled water system. The control building chilled water system is redundant and consists of two 100 percent capacity water chillers, two 100 percent capacity chilled water pumps, end two expansion tanks. Each chiller is rated at 250 tons of refrigeration. Each chilled water pump is rated at 450 gpm. The chilled water piping is arranged in two redundant flowpaths to serve the control building air-conditioning unit cooling coils.

Each air-conditioning unit cooling coil has a flow controi valve controlled by a thermostat in the respective area. The differential pressure control valve automatically maintains constant return flow to the chilled water pump by modulating bypass flow in proportion to varying air-conditioning system flow.

All Category I electrically-powered motors and controls associated with the control building air-conditioning and ventilation systems and the chilled water systems are redundant to

(

cnsure operability of the control building air-conditioning and ventilation as a result of a single failure of any ' omponent. In the event of a loss of power under either normal c

operating or accident conditions, emergency power is supplied from either the preferred offsite source or the emergency diesel generators.

I All outside air supply and exhaust ducts for the control room pressure envelope air-conditioning system, kitchen-toilet exhaust system, and purge system are fitted with air-l operated butterfly valves located as close as possible to the control building wall.

l The control building is heated electrically. Area thermostats activate heating elements in the control room air-conditioning units to maintain a minimum design temperature. A control switch activates heating elements in the instrument rack and computer room air-conditioning units in the event heating is required. The mechanical equipment space is heated with electric unit heaters that are controlled separately from thermostats located in the room. The chiller equipment space is heated with electric duct heaters and electric unit l

heaters that are controlled separately from thermostats. Electric heaters are not required to function following loss of offsite power.

The control building purge ventilation system removes smoke or carbon dioxide from the inst'ument rack and computer room, the cable spreading area, switchgear r.ooms, and the mechanical equipment room (zoned with the control room) through administrative controls.

l The system is designed to permit the operator to purge each space containing smoke or carbon dioxide by opening the supply and exhaust purge isolation dampers from outside that space.

f

(.

! CS4.MPs 9.4-4 January 1998

98.mP3-noo INSERT B After one hour, realignment of the control room ventilation system from the

. initiated. In the event of a LOCA, p:! : te Oper5;; the h!ct !:r!

pressurization mode to the filtration / recirculation mode of operation can be operator action is credited to secure selected Main Steam Valve House, Auxiliary Building and Emergency Safeguards Features Building exhaust fans, specifically fans 3HW-FN1 A&18,3HVR-FNS&7 and 3HVQ-FN2 are secured. This action is to ambient pressure. The isolation valves are #wd$ pen % room will depre completed within 20 minutes during which time the cog ed, to divert outside air through the control room emergency ventilation filter. In the event that the inlet isolation valves fail to open, operators are able to open these valves one hour l

and 40 minutes following a CBl.

galW l

MNPS-3 FSAR

" ?"f D -l C O

~. 4.1'. 3 Safety Evaluation 9

The control building air-conditioning. emergency ventilation filtration, and chilled water systems are Seismic Category I and QA Category I. Ventilation, except for the kitchen-toilet exhaust and the purge system, are Seismic Category I and QA Category 1. All of the systems are enclosed in a Category I missile-and tornado-protected building.

The control building habitability envelope air bottle pressurization system is designed to ASME B and PV Code Section Vill, Division 1 and ANSI B31.1 standards.. The air pressurization system is designed to Seismic Category I requirements.

A radiation monitor connected with the makeup air duct of the control room area air-conditioning units detects and respond to the presence of radioactivity. At the discretion of the operator, the emergency ventilation system can be started manually and the return cir of the control room or the outdoor air supply diverted through the emergency ventilation filtration assembly.

High radiation detected by the monitors located in the air intakes result in control building 49%

i:olation (Section 6.4).

13 5/

l During control building isolation, the air bottle pressurization subsystem supplies breathable gir and maintains a positive pressure within the control room envelope. The air is discharged to the 64'6" elevation, from where the balanceo control room air conditioning _ (9g]

units maintain eaual pressure between the two elevations of the envelope.lThe air intake T Tolation valves can be opened and emergency ventilation started following 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of air

\\

p bottle pressurization. These valves and emergency ventilation filter fans are manually

'p#

operated from the main ventilation panel in the control room. The valves are located within the habitability zone and can be opened,in the event either valve fails to open by manual cctivation, with a rack screw operation. This design enables these valves to be opened j

( within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> following control room isolation.

The storage bottles are normally refilled via breathing air quality compressors. These are located in the turbine building. Additionally, a fill connection is located on the outside wall of the turbine building. Refilling is usually accomplished using breathing air quality air

%5o3 9

compressors. Alternately an air tank truck can be on site within 3 days for refilling D

purposes.

Fusible link fire dampers are provided on openings in fire barriers separating fire areas. The f

l dampers automatically isiolate the area affected by fire. Fire damper assemblies installed in ventilation ductwork common to redundant portions of this system consist'of at least two fire dampers in parallel in order to preclude a single failure of one fire damper from impairing the safety function of the system. Administrative controls to shut down control room air-conditioning units in the event of a fire detection alarm within thesontrol' room envelope are used to ensure' fire da~mper closure if a fire exists. Airtight doors;; sealed

~

penetrations and fire walls prevent smoke, heat, and carbon dioxide from enteririg the.

control room. A purge system is provided to remove smoke and carbon dio'xide'from all creas except the chiller room which has 100 percent outside air circulation. The purge

[q1-3g

. system shares a common air intake duct, but is operated completely independent 'of all

( Sju /

- control building air-conditioning and ventilation systems. The largest area served by the purge gystem can be ventilated at a rate of approximately one air change per hour.

January 1998 [

, nGP3 '

9.4-5 f

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38.mp5-st>o I

i l

INSERT C l

After one hour, realignment of the control room ventilation system from the pressurization mode to the filtration / recirculation mode of operation un be tf j n the event of a LOCA, pr!ct ic Oper:ng the in!ct !ce!ctier vc!ved 460

_ initiated i

t@! cec!cn; "At" the e =ergency '"ter fcne cre -cnuc!!y cpercted ' rem the main t,enme+r n ngne! in the enn+,9! ree,", operator action is credited to secure e

selected Main Steam Valve House, Auxiliary Building and Emergency I

Safeguards Features Building exhaust fans, specifically fans 3HW-FN1 A&18, 3HVR-FNS&7 and 3HVQ-FN2 are secured. This action is completed within 20

]

minutes during which time the control room will depressurize to ambient pressure. The isolation valves are then-opened, to divert outside air through the control room emergency ventilation filter,""t"'n ene hcur and t;;cnty.T.inutc:; gdgt9Y fc"cr;'n;; c C9!

j 1

Cln the event the inlet isolarn valves fail to open, operators are able to manually

)

~

open these valves using the manualjack screw operator. Since the location of these valves is within the control room habitability zone and the valves are designed for manual manipulation, control room personnel are able to open these valves within one hour and forty minutes following control room isolation.

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MNPS-3 FSAR TV - nf3 - j oa p

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in normal operation, the chilled water pumps are not affected by a CBI signal. The CBI signal prevents the running purnp from being manually stopped from the control room.

The chillers are provided with ON-STOP chiller safety circuit push buttons and START-I STOP pushbuttons for local manual control. The chiller safety circuit is normally ON for

- both chillers. The chillers are started automatically when the associated chilled water.

pump is started.

l Control room air-conditioning unit heaters are controlled by automatic temperature controllers. Instrument rack and computer room air-conditioning units are controlled by temperature switches in the event heating is required.

i The control room pressure envelope area is automatically isciated frorn the outside atmosphere upon receipt of a CBI signal, and 60 seconds after a CBI signal is initiated, the p

j control room is automatically pressurized with air from the control room pressurizing air

- f /-

9 i

storage tanksJese air te As have a 1-hour supply of air. After this timefan emergency ventilation filtration train can be manually started to maintain pressurization of the control room.

e.

A CBI signal is initiated when any of the following conditions exist:

j air-intake radiation high; containment pressure high 2 out of 3 signal; l

manualinitiation from main control board;

(

manualinitiation from main heating and ventilation; or manual safety injection signal.

a The control building ventilation makeup dampers and the control building isolation valves have control switches and indicator lights on the main heating and ventilation panel.

Engineered safety features status lights on the main control board indicate when the valves and dampers are closed. The opened and closed positions are monitored by the plant computer. The control building air makeup dampers and isolation valves are automatically closed on receipt of a CBI signal.

Control switches and valve position indicator lights are provided for the air storage tanks' outlet valves on the main heating and ventilation panel. Engineered safety features status lights on the main control board indicate when the valves are open, and the open and closed positions are monitored by the plant computer. The air storage tanks' outlet valves are opened automatically after a time delay on receipt of a CBI-! nal.

D The chiller equipment space supply fans have control switches and indicator lights on the main heating and ventilation panel. The exhaust fans are interlocked to start and stop with the associated supply fan. One train is normally running with the other train on standby.

The purge supply fan is interlocked with the purge supply damper. The supply fan is started when the supply damper is opened and stopped when the damper is closed. The

' January 1998 !

I es4.wa.

9.4-8

97 'ttt'3-t 00 INSERT D realignment of the control room ventilation system from the pressurization mode

. to the filtration / recirculation mode of operation can be initiated as described in section 9.4.1.3.

1 i

l

7tf Tf6

/0o MNPS-3 FSAR ga p activities to the reactor coolant. The gap activity is assumed to be released irvlanta-(

neously into the containment atmosphere via the break in the reactor vessel head. In I

cddtion,it is further postulated that 0.25 percent of the core fuel experiences melting l

resulting in 100 percent of the noble gases and 25 percent of iodines in the fraction of l

melted fuel to be available for release from the containment. The releases to the environ-l N

ment are assumed to take place from the secondary system until such time that the I

secondary system pressure decreases below relief valve actuation. The containment building releases are assumed to last for 30 days after initiation of the accident. Activity released from the secondary ~ system is derived from the technical specification primary to

~

secondary leakage of reactor coolant containing activity associated with tect alcal specifi-cation fuel defects, releases from fuel with clad damage, and 100 percent of the noble gases and 50 percent of the iodine contained in this fraction of fuel assumed to have melted. Releases from the secondary side are evaluated assuming coincident loss of offsite power. Pertinent parameters used to describe the :--- " " releases are presented in Tables 15.4-4end 15.4-6 pod 65.G.') ( r.t-d,

y e.as s-W.e m.AA%m.aa u -* *

, hagg Assumptions regardeng the time for the secondary containment to achieve negative c Mem.ne,tt, sfgg' l pressure are the same as that which was used for the LOCA analysis. The bypass leakage 1 (2.g is released unfiltered to the environment at ground level. The leakage which is not bypass leakage is assumed to be processed by the secondary containment filtration system. Nwe. 4t.hAd l

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av.c,a.4p u c4 ce< h nrownh k vAsg, n %,4.o 6.b.5 4

~

or purposes of conservatism, all collected leakage is assumec to exhaust via a reIease 4

point located above the turbine building. This assumption is made as a result of the 4'M D simultaneous operation of the charging pump ventilation supply and exhaust system which 1

may entrap and filter some fraction of containment leakage as described in Section 9.4.3.

(-

M This effluent is analyzed as a ground level release.

N The releases, together with the atmospheric dispersion factors listed in Table 15.0-11, are 32 %l used to compute the doses to the EAB (0-2 hr) and LPZ (0-30 days).

The radiological consequences of a postulated rod ejection accident are analyzed (for both N-loop and N-1 loop operation) with the information contained in Regulatory Guide 1.77 and the Standard Review Plan 15.4.8. For the N-1 loop analysis, it is assumed that the plant had been in N-loop operation at full power sufficiently long to achieve equilibrium core activities and coolant concentrations. The plant then began N-1 loop operation, shortly after which the rod ejection accident occurred. The calculated dose results (for both the N-loop and the N-1 loop analyses) described in Table 15.0-8 for the rod ejection accident are presented separately for the releases from the containment building and the releases via the secondary system.

j,g The radiological consequences of the postulated rod ejection accident are within the guide-lines of 10CFR100:1.e.,75 Rem to the thyroid and 6 Rem to the whole body.

15.4.9 References for Section 15.4 Bishop, A.' A.; Sandburg, R. O.: and Tong, L. S.,1965. Forced Convection Heat Transfer at High Pressure After'the Critical Heat Flux. ASME 65-HT-31.

Liimataninen, R. C. and Testa, F. J.1966. Studies in TREAT of Zircaloy 2-Clad, UO Core k

2 Simulated Fuel Elements. ' ANL-7225, January - June 1966, p.177.

March 1998 !

iss4.w a 15.4-36

Y ' W3 - /D O e

MNPS-3 FSAR 9

filtered air into the control room. @rinn this 40 minut eriod. 230 cfm unfiltere 97 inleakage is assumed] During^the period of pressurization,115 cfm of unfiltered inteakage 3MS is assumed.

t.hs 40 fnMh., pe. nod a.d Release Pathways The release pathways to the environment subsequent to a lo wof-coolant DBA are leakages from the containment building and ESF systems, which are collected and processed, and leakage from the containment building which is assumed to bypass SLCRS.

Containment Leakaae Pathway The containment is assumed to leak at the design leak rate for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the accident.

[

After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, since the pressure has been decreased significantly, Regulatory Guide 1.4 allows the containment leakage to be reduced to one-half the design leak rate. For the i

dose calculations to the Control Room and Technical Support Center, a reduced contain-ment leak rate was assumed at T = 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. This was justified and approved as part of the Amendment that eliminated the post-LOCA negative pressure containment requirement. It

(.n,.4 is based on the fact that the Millstone Unit 3 containment pressure is rapidly reduced w/

compared to typical PV/Rs because of its original design as a negative pressure contain-ment.

The collection, processing, and release of containment leakage varies depending on the location of the leak. Ventilation characteristics and release paths are different for each h n) building comprising the secondary containment.

~.wo emerency ver.tilation systems collect most of the containment leakage and process it through HEPA an6 charcoal filters. The SLCRS exhausts from the containment enclosure, auxiliary, ESF, and the main steam valve buildings, and the compartment of the hydrogen recombiner building abutting the containment. SLCRS flow'is filtered and released through the Unit 1 stack. The charging pump, component cooling water pump, and heat exchanger area portion of the auxiliary building ventilation system (ABVS), described in Section 9.4.3, supplies and exhausts a relatively high flow on the 24 foot-6 inch elevation floor of the MW auxiliary building. The exhaust flow is filtered and released through the ventilation vent on

)

he roof of the turbine building.

g 7

T

[The specific areas of the sdcondary containtnent into which the primary containment will leak cannot be predicted. Some areas would be released primarily through the filters to the MP3 ventilation vent. Other areas may have some bypass leakage paths, but the majority of the activity would go through filters to the elevated MP1 stack. An analysis was q 7.g JC*

performed to determine the worst case location for assumed containment leakage. It was f,

determined that the assumption that all containment leakage is into the 24' level of the h

auxiliary building and is released instantaneously (no mixing) through filters to the lower ventilation vent release point bounds any more mechanistic analysis which would include'

[ mixing, some bypass and elevated releases.

Credit is taken for iodine removal due to containment sprays during the duration of the hM accident. Assumptions pertaining to the spray system are listed in Table 15.6-9.

15.6-24 March 1998 issamm

38. ro P 3 - f oo

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INSERT E All containment leakage is collected and filtered by these 2 the following:

or

1. The fraction ofcontainment leakage which is assumed to bypas secondary containment. This is assumed to be an unfiltered ground release to the environment.

2. The initial containment leakage during the 2 minute time pe SLCRS to establish negative pressure conditions. This is assum unfiltered ground level release to the environment.

3. The leakage past closed dampers which isolate non-ESF ve MYg the auxiliary, ESF and main steam valve building. This leakage he an unfiltered ground level release to the environment For Cont e o p0 habitability the main steam valve, auxiliary and ESF building normal exh om QD portions ar secured prior to placing the control room ongunergenc9 venttiatien. For TSC habitability, the~ main stearn valve and 46

. normal exhaust portions trip upon receipt of a SIS signal. The E F normal exhaust is secured locally prior to I hour 20 minutes post LOC.

4. The ductwork leakage from the auxiliary building into the S RS and emergency portion of the ABVS between the filter and leakage is released unfittered, along with the rest of t exhaust fan. This flow for these systems, through the Unit I stack for the SLCRS ow and through the ventilation vent for the ABVS flow.

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i MNPS 3 FSAR TABLE 15.0-8 9i POTENTIAL OFFSITE DOSES DUE TO ACCIDENTS Dose (rem)

Dose (rem) 2 hr Exclusion Low Population Area Boundarv (524 m)

Zone.(3862 m)

Postulated FSAR Accident Se, ction 1hvroid Gamma Thyroid Gamma Steam Generator Tube Rupture 15.6.3 a.' Preaccident iodine spike 2.1 E+ 00 1.9E-02 2.4E-01 1.2E-03 b.. Concurrent

. iodine spike 3.4E-01 1.8E-02 7.6E-02 1.1 E.

LOCA 15.6.5 1.4E + 02 '

9.4E + 0088 3.OE+ 0183 1.7 E + 0058 5

ii:

Waste Gas System Failure 15.7.1 0.OE + 00 2.2E-01 (2)

(2)

)

Radioactive Liquid Waste System Leak or p

Failure (Atmospheric Release) 15.7.2 4.3E-01 4.7E-04 (2)

(2)

Fuel Handling Accident.

15.7.4 7.6E + 00 5.1 E-01 (2)

(2)

Spent Fuel Cask Drop 15.7.5 (3)

(3)

(3)

(3)

)

c NOTES:

p3 O(92.

e" gpg h,0

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l.

(1) 1.6E-01 = 1.6 x 10

O (2) 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of release o less; a 30-day dose is not applicable.

T (3) Not applicable-so Sections 15.7.5.2 an 15.7.5.3.

g,og4.o g

4) The current rod ejectio analysis result i an EAB thyroid dose of 0.0- ; 00, an,EAB gamma l'OE-on

. dose of'.00-01, an thyroid dose of 4.0 100 and an tee gamma do

-ef._

E-02. The current 'results are bounded by the licensed numbers listed in the table. O,0C:::

M' (5).The current LOCA analysis result in an EAB thyroid dose of *.0" :02, n amma dose of

53g,

^ 2. 00, a' tPlHhyroid dose of 9.95 ' On and an L-Pe gamma dose of 1.3E+00. The current g

results are ounded by the license numberslisted in the table.

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'2 of 2 March 1998

-___=_-_=_______2_____

78 1/f'3 -- /00 MNPS-3 FSAR TABLE 15.0-11 ATMOSPHERIC DISPERSION DATA USED FOR DESIGN BASIS ACCIDENT ANALYSIS EAB X/Os (see m )

4 2

Ground level release-containment 0-2 hr.

5.4 x 10" 4

Ground level release-ventilation vent 0-2

- 4.0 x 10' \\.0 X \\0 4 hr.

Elevated release-Unit 1 Stack 0-2 hr.

7.0 x 104 LPZ X1Qs (see m )

4 g

Ground level release-containment 0-8 hr.

2.9 x 10-5 x

Ground level release-ventilation vent 0-8 hr.

2.9h 10-5 8-24 hr.

%a% 4:fr x 10 5 1-4 days 8 nedj 104 4-30 days 2.tQc 104 E~b E evated release-Unit 1 stack z.(A x to"6

[9-8 hr.

0.00 x 10*

t.o7 m.1M 8-24 hr.

2.00 m 10*

6.~17. X 10- 6 1-4 days 1.0; 10' 2..% x to-6 4-30 days

,)

0.00 m 10' s.g3 x go~7

_ Millstone 1 Millstone 2 Millstone 3 Control room X/Os (see m )

4

a. Ground level release-containment 0-8 hr.

3 1.9 x 104 8-24 hr.

1.4 x 10-81.57 xic 0.00 x 10" 1.3 x 104 1-4 days 9.7 x lod 653xic 5.43 4 iG4

%A 4.2 x 104 3.4 x 1042.5%to"1.05 10d D

4-30 days 3.8 x 104 8

2.7 x 10'S 32.txid 2.70 m 10'5 O-24 hr"'

NA.

24-36 hr""*

8.7 x 10'5 NA NA 5.2 x 10~5 NA

b. Elevated release-Unit 1 Stack 23 O-4 hr.

1.6 x 104 1.6 x 104

-t#t I?A Ato4 4-8 hr.

4.4 x 104 4.4 x 104

,, g 8-24 hr.

NA 3.?f,3 to 2.4 x 104

'2.4 x 104

-NA-137 510 1-4 days

-t#e ).56 x ic'_

6.3 x 10" 6.3 x 103 4-30 days 9.3 x 104 9.3 x 10*

NAl.M Xid' O 24 hr."'

NA 2.0 x 10*

NA 24-3G hr.""5 NA 1.2 x 10-8 NA

c. Ground level release-ventilation vent 0-8 hr.

NA 3

~

8-24 hr.

NA 3.75gio -2.24 m 10

NA 1-4 days NA g,g f 3 '. 40 a 10' (g.Q NA 4-30 days NA 7 43x ic'4 5 CC ^ 10" NA MSEt T NA g,gg-S 0.00 x 10'5 5"

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'~

9[-MID-l00 JNSERT F

d. Unit 3 MSVB 0-8 hr

'N/A N/A 5.78E-3 8-24 hr N/A N/A 3.20E-3 1-4 days N/A N/A 9.52E-4 4-30 days N/A N/A 9.16E-5

- c. Unit 3 ESFB 0-8 hr N/A N/A 4.86E-3 8-24 hr N/A N/A 2.69E-3 1-4 days N/A N/A 8.00E-4 4-30 days N/A N/A 6.77E-5

f. Unit 3 RWST 0-8hr N/A N/A N/A 8-24 hr N/A N/A 8.53E-4 1-4 days N/A N/A 4.32E-4 4-30 days N/A N/A 8.03E-5 i

s

.m

[ '- M P 3 A O O J

MNPS-3 FSAR 1

TABLE 15.O-11 l

ATMOSPHERIC DISPERSION DATA USED FOR DESIGN BASIS ACCIDENT ANALYSIS TSC X/Qs (sec./m*)

Millstone 1 *'

Millstone 2

Millstone 3 8

a. Ground level release-containment 3

4 4

4 0-8 hr.

1.9 x 10 1.4 x 10

0. ',10 1.5 7. xt o, 4 4

d 8-24 hr.

1.3 x 10 9.7 x 10 2.7 m "O'4.T1xto 4.2 x 10 3.4 x 10

.0x10"2.59wIo'4 4

d 1-4 days d

4-30 days 3.8 x 10 5 2.7 x 10-5 2.0 x 10-5 3,qi x go 4

0-24 hr"'

NA 8.7 x 10 NA 24-3 6 hr.""*'

NA 5.2 x 10-5 NA

b. Elevated release-Unit 1 Stack

-NA-t.39 m o~ +

d d

0-4 hr.

1.6 x 10 1.6 x 10 4

4

-5 h 8 hr.

4.4 x 10 4.4 x 10 HA 3,23 xgo 4

4 6J 8-24 hr.

2.4 x 10 2.4 x 10

-N A 1, w.g o -fe 4

4 1-4 days G.3 x 10 6.3 x 10 MA ),qqxio-6 4-30 days 9.3 x 10*

9.3 x 104

-NA g,gg gg 7 4

O-24 hr."'

NA 2.0 x 10 NA 24-36 hr."" '

NA 1.2 x 104 NA

c. Ground level release-ventilation vent

_g 0-8 hr.

NA NA 2.0 C 3.*iS X c 8-24 hr.

NA NA C.7E ' ).14 h 10~3 1-4 days NA NA

'CC' q.qxgo-4 4-30 days NA NA 7.5E-5 q,d g go-S

.Ltl%9,T NOTES:

1.

High wind speed condition only (no fumigation).

2.

Fumi ation conditions assumed for 0-4 hour period.

0 3.

X/O values for Unit 2 high wind speed condition after 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> are the same as for low wind speed condition.

4.

Control room X/O values are applicable to the TSC due to the proximity of the air intakes of the two buildings.

2 of 2 March 1998 t

___.AE___

f 9[~ MP3 -lOO INSERT K

d. Unit 3 MSVB.

0-8 hr N/A N/A 5.78E-3 8-24 hr '

N/A N/A 1.60E-3 1-4 days N/A N/A 9.52E-4 4-30 days N/A N/A-9.16E-5

c. Unit 3 ESFB 0-8 hr N/A N/A 4.86E-3 i

8-24 hr N/A N/A 1.35E-3 1-4 days N/A N/A 8.00E-4 4-30 days N/A-N/A 6.77E-5

f. Unit 3 RWST 0-8hr N/A N/A N/A 8-24 hr N/A N/A 4.27E-4 1-4 days N/A N/A 4.32E-4 4-30 days N/A N/A 8.03E-5 7

1

$ Y' N Y3 -/00 i

MNPS-3 FSAR TABLE 15.4-4 PARAMETERS USED IN ROD EJECTION ACCIDENT ANALYSIS Analysis Inout Parameters N-Looo N-1 Looo 1.

Core thermal power (MWt) 3,636"3-3,636"8 2.

Containment free v31ume (ft*)

2.32x10' 2.32x108 3.

Primary coolant Table Table concentrations 15.0-10 15.0-10 4.

Primary to secondary leak rate (gpm)'

1.0 1.0 5.

Secondary coolant Table Table concentration 15.010 15.0-10 S. ' '.' :9; :d

'Y1 % v.

G, i. Failed fuel'as a result D

of the accident (%)

10.0 10.~0 7 4. -Core and gap activity Table Table 15.0-7 15.0-7 6 K.

Quantit9 of fuelin the core which melts as a result of the accident

(%)

0.25 0.25

'9 4&. Quantity of radio-nuclides from the melted fuel available for release from the containment (%)

a. lodine 25.0-25.0

b. Noble gases 100 100 15s4 4.'ues -

1of3' March 1998 c_ _ -_ ____ -_

E-

~ N 2~/00 MNPS-3 FSAR TABLE 15.4-4 l

PARAMETERS USED IN ROD EJECTION ACCIDENT ANALYSIS Analysis Inout Parameters N-Looo N-1 Looo 10

-W.. Quantity of radio-nuclides from the melted fuel avail-able for release frorn the secondary side via primary-to-secondary leakage (%)

a. lodines 50.0 50.0

b. Noble gases 100 100 11

+2'. lodine partition factor l

4.py g in steam generator prior 3/97 to and during accident 0.01 0.01 s'2.

M. Offsite power Lost Lost i3 W. Steam dump from relief valves (Ib) 40,604 40,604 14

+85. Duration of dump from relief valves (sec) 125.0 125.0 1F 4&. Containment leak rate

(% per day)

a. O-24 hrs 0.30 0.30

b.24-720 hrs 0.15 0.15 W. Bypass leakage (fraction of containment leakage) 0.042 0.042 17

46. Time between accident and equalization of primary and secondary pressures (sec) 140.0 140.0 l&~Lu,L Tnn.nE SIS (min l

W/A

19. Time estimated for SLCRS to become effective

(

(min) 2 2

iss4 4.wa 2 of 3 March 1998 l

T& MP3-too o,

MNPS-3 FSAR TABLE 15.4-4 PARAMETERS USED IN ROD EJECTION ACCIDENT ANALYJ_IS Analysis Inout Parameters N-Looo N-1 Loon cl7- %

Stir

20. Duration of leakage from containment (hr) 720.0 720.0 l( "*[

j

21. lodine removal filter efficiency (%)

95.0 95.0

22. Steam generator contents (Ib/SG)

a. Steam 8,000 7,600

b. Liquid 103,000 104,000

23. Primary coolant mass (Ib) 520,000 350,000*

2A, CRCbiT Se 6Pr*%S Wo WlA NOTES:

1.

Fuel gap activities are based on reactor power of 3,636 MWt.

~

2.

In the N-1 loop operation analysis, the pressurizer volume has been conservatively excluded from the primary coolant.

(

25. Iow fT,ka\\ h n

'IC RP 30 N/A D h:, bnuerkon FAc.,s g 1534-4 MP3 3 of 3 March 1998

/

$5'W3 kco gM

,f MNPS-3 FSAR TABLE 15.6-9 ASSUMPTIONS USED FOR THE RADIOLOGICAL CONSEQUENCES lyj r OF A LOCA ANALYSIS i. Power level (MWt) 3,636 p,g

t.. Coro inventory Table 15.0-7 --

3 todine composition l

l Elemental (%)

05.5 98 Particulate (%)

2:5-E l

Organic (%)

2:0-4

4. Fraction of core inventory released into reactor coolant lodine 0.5 Noble gas 1.0 hf[y }

q

- 2.

5. Fraction of reactor coolant inventory available for release from containment lodine 1.0 Noble gas 1.0

6. Core inventory, available for release from contain-ment lodine (%) 2.5 Noble gas (%)

100

7. Containment free volume l

(ft')

2.

10'

8. Containment leak rate (percent per day) 0-24 hr 0.30 Qt.#[

24-720 hr 0.15

9. Bypass leakage (fraction of containment leakage) 0.042 97-ur.

Elemental I

p ?!

r 5, /[/IZ.

s o. Secondary %nclosure time-toTeach negative pressure (100% bypass assumed) 2 min.

f %' r^ 'd l

e pY l\\p.4,{

S1 5550 * *'2 1 of 2

-Mereh1998

Tlf' M 3 400 g 'i 118 MNPS-3 FSAR g

TABLE 15.G-9 ggg ASSUMPTIONS USED FOR THE RADIOLOGICAL CONSEQUENCES yg i OF A LOCA ANALYSIS

_l

~

ht Is. ha #}h24YWNS Y

~

Volume of sprayed region = 1.17 x 10' x ft*

n.

Volume of unspra'yed region = 1.15 x 10' ft*

//t2d Maximum iodine DF during spray operation =

qtt Quench spray operatior) initiation time =

$-[/ StO

)

Mixing rate between sprayed and unsprayed regions = z turnovers /hr

[

lodine removal rates in sprayed region:

{~,* (

Actem = 20.0/hr Apart =

7ll1 W

d-Duration of release fror b

,gg, containment (br) 720 Post-LOCA Eauiomont Leakane Leak initiation and cessation timos 220 sec to 720 hr 11-i 4tLl Maximum operational leak rate (cc/hr) 5,000*

ECCS LEAccGi bMW6M GWkii.SF6 e o.6%3 2A o El' "C

l Fraction of core iodino inventory in sump water 0.50 Sump water temperature ( F) 256- < 212 lodine release to building atmosphere from recirculation

'q'td leakago (%)

10m Filter efficiency Elemental iodine (%)

95 Methyl iodine (%)

95 HEPA (%)

95 NOTES:

{

qi.

"l' 1.

Includes instrument error of 2 percent.

2.

Despite temperature variation, at no time is there greater than 10 percent of the water in the sump flashing to steam.

ii.]

3.

In accordance with SRP 15.6.5 Appendix B, Revision 1, the calculation assumed the maximum post-LOCA equipment leakage was a factor of two times the max operational leaka00 to give a totalleakage of 10,000 cc/hr.

• / h

[\\ r. :\\ March 1998 4,k.

' 65* 8 *'3 2 of 2

W ' rW3 -to o INSERT G

11. Length of Time QSS is in Operation:

7480 sec

12. Spray Coverage 50.27 %

13. Maximum Iodine DF After Instantaneous Plateout 200

14. Quench Spray Effective Time 70.2 sec

15. Mixing Rate for Unsprayed to Sprayed Regions 70.2 - 780 sec:

2 780 - 830 sec:

9.99 830 - 2700 sec:

13.32 2700 - 4330 sec:

8.41 4330 - 7480 sec:

6.95

16. Sprayed Region Elemental Iodine Removal Coefficients (hr-1) spray 20 plateout 5.1

17. Sprayed Region Particulate Iodine Removal Coefficients (hr-1)

<DF 50 12.7

>DF 50 1.27

18. Unsprayed Region Elemental Iodine Removal Coefficients (hr-1) spray 0

plateout (0 - 1800 sec) 1.2

19. Unsprayed Region Particulate Iodine Removal Coefficients (hr-1)

<DF50 0

>DF 50 0

20. No credit taken for iodine removal after QSS stop time

21. Percentage of Total Containment Leakage into the Se.condary Containment ESF building 10.59 MSV building 23.64 H2 Recombiner building 0.51 Containment Enclosure 7.77 Aux. bldg, El. 4'-6" 12.43 Aux. bldg, El. 24'-6" 21.08 Aux. bldg, El. 43'-6" 20.82 l

Aux. bldg, El. 66'-6" 3.17 l

22. Secondary Containment Free Volume (f13)

ESF building 168,373 MSV building 70,000 112 Recombiner building 15,000 Containment Enclosure 816,000 Aux. bldg, all elevations 913,500

23. 50% mixing in buildings that together form the secondary containment

24. Unfiltered leakage via closed dampers occur in Aux, MSV and ESF buildings

Qlr - ri t*3 -l 00 b m r b OonT'o)

25. Unfiltered releases occur from ventilation vent, Unit I stack, ESF bldg roof vent and MSV bldg roof vent

26. Site boundary case: leakage values based on single damper closure, leakage occurs for 30 days

27. Ventilation and Leakage Parameters T=0 hrs to T=30 days Post-LOCA Ground Level Release efm 3HVQ-FN2 (ESF bldg normal exhaust) 77 3HVV-FN1 A&B (MSV13 exhaust) 134 311VQ*ACUSl A&B (ESF bldg AC) 4 3HVQ' ACUS 2A&B (ESF bldg AC) 2 Unit 1 Stack l

3GWS-FNI A&B (Process Vent Fan) 70 (Aux 66'-6")

3HVR*FN12A&B (SLCRS exhaust - duct leakage) 63 (Aux 66'-6")

Ventilation Vent 311VR-FN5 (Aux bldg normal exhaust) 553 (Aux 43'-6" & 66'-6")

3HVR-FN7 (Aux bldg normal exhaust) 218 (Aux bldg - all ele) 3HVR-FN8A&B (Waste Disposal bldg normal exhaust) 43 (Aux bldg 66'-6")

3HVR-FN11 ( Electrical Tunnel purge air) 28 311VR-FN9 (Fuel bldg exhaust - duct leakage) 75 (Aux bldg 66'-6")

311VR*FN6A&B (Aux bldg filter exhaust) 17 (Aux bldg 66'-6")

3HVR*AOD44A&B (Normal exhaust isol) 113 (Aux bldg 24'-6")

l 3HVR* AOD32A&B (Containment purge exhaust) 118 (Aux bldg 24'-6")

l 4

[{"M/'3 -/OD MNPS-3 FSAR -

TABLE 15.612 ASSUMPTIONS USED FOR THE CONTROL ROOM HABITABILITY ANALYSIS Control room (CR) parameters:

Control room volume (ft*)

238,226 Control building concrete wall i

thickness (ft) 2 l

l l

Filtered ventilatier. intake rate.

97-m N

post CR isolation (cfm) 230 Filtered recirculation rate post CR isolation (cfm) 666j97Mah inleakage rate (cfm)-

10 (115 cfm for Time to place ventilation on recirculation assuming loss of 17 g instrument air 40 minutes Inleakage after depressurization ggg-until recirculation 19&cfm Intske ventilation filter efficiencies (percent):

HEPA 95 Charcoal (methyl and elemental) 95 eration of isolation (r..-)

61 suration of unfiltered intake prior 3,%

to control room i.c:ation (sec) 5.7(2' (-

R: lease points (distance to Unit 3 control room intake in meters):

Unit 1 turbine building 320 Unit 1 stack 351 Unit 2 containment surface 223 Unit 3 containment surface 72 Unit 3 reactor plant ventilation vent 38 Y

Control room air intake height 12.3 (

%.,..T5fi WO

1. See Table.1.9-2, SRP 6.5.1, Section B.5.

/ 2. For analyA's of assumed LOCA at either Millstone Unit 1 or 2. The duration of unfiltered inleakage is 5.7 seconds to accourit for 3 seconds for radiation n.onitor response,3 seconds for isolation tv w.

. damper closure, with 0.3 seconds of activity trapped between radiation monitor and isolation

. damper. Other Unit 1 and Unit 2 LOCA assuroptions are given in the following references:

+,_

l isse s2.ws..

1 of 2 March 1998

)

g-N W3 J/ oo

-INSERT H Leakage values based on single damper closure e-3HVV-FNI A/B,3 HVQ-FN2,3HVR-FN5 and 3HVR-FN7 are locally secured prior e

. to I hour 20 minutes post-LOCA.

Ventilation and Leakage Parameters T=0 hrs to T=30 days Post-LOCA.

Ground Level Release cfm 3HVQ-FN2 (ESF bldg normal exhaust) Note 1 77 3HVV-FN1 A&B (MSVB exhaust) Note 1 134 3HVQ'ACUSl A&B (ESF bldg AC) 4

[.

_3HVQ' ACUS 2A&B (ESF bldg AC) 2 Unit 1 Stack 3GWS-FNIA&B (Process Vent Fan) 70 (Aux 66'-6")

3HVR*FN12A&B (SLCRS exhaust - duct leakage) 63 (Aux 66'-6")

Ventilation Vent 3HVR-FN5 (Aux bldg ncrmal exhaust) Note 1 553 (Aux 43'-6" & 66'-6")

3HVR-FN7 (Aux bldg nirmal exhaust) Note 1 218 (Aux bldg - all ele) 3HVR-FN8A&B (Waste Disposal bldg normal exhaust) 43 (Aux bldg 66'-6")

3HVR-FN11 ( Electrical Tunnel purge air) 28 3HVR-FN9 (Fuel bldg exhaust - duct leakage) 75 (Aux bldg 66'-6")

3HVR*FN6A&B (Aux bldg filter exhaust) 17 (Aux bldg 66'-6")

3HVR* AOD44A&B (Normal exhaust isol) 113 (Aux bldg 24'-6")

3HVR*AOD32A&B (Containment purge exhaust) 118 (Aux bldg 24'-6")

Note 1: These fans are secured at I hour 20 minutes post-LOCA and the bypass flow is terminated.

h_.' F_.i

$ [ _W"100 0\\

d}.g,9' MNPS-3 FSAR ~

TABLE 15.6-13 DOSE TO MILLSTONE 3 CONTROL ROOM ASSUMING LOCA REI FASE FROM MILLSTONE 1,2 AND 3 RESPECTIVELY Thyroid Whole Body

~

" ~ Bete Dose Gamma Dose Skin Dose

Release From Itaml 1r.grR1 iteml Millstone 1 6.OE v00 1.7E-01 1.3E + 00 Millstone 2 (Iow wind speed condition) 2.8E + 01 9.OE-01 1.2E + 00 (high wind speed condition) 1.6E'+ 01 1.1 E 3.8E-01 Millstone 3 2.60E + 01'28 3.1 E + 00*

2.5E + 01m 2}tY (4s a2 Htt NQIE:

l' (93 a;

1. 6.OE + 00 = 6.0 x 100

2. The current Control Room LOCA analysis result in a thyroid dose

+01, a whole body qI,92

+01. The current results c:e bounded gamma dose oly+00 and a beta skin dose ofp(

by the licensed numbers listed in the table.

..,L~

I.

bgf.A6

~

(S f

g T.

~1.'

March 109%

1 a_

1 Cf f -M l'] - PD D MNPS-3 FSAR j

TABLE 15.6 DATA USED IN THE TECHNICAL SUPPORT CENTER HABITABILITY ANALYSIS TSC Buildina Parameters

~

s Free air volume (ft )

33,200 Concrete wall thickness (ft) 2.0 Concrete roof thickness (ft) 1.0 infiltration rate during isolation (cfm) 50 Ventilation Parametms 11 91f.

ShV Duration of isolation (min) 30 Intake rate prior to isolation (cfm) 100 Intake rate postisolation-filtered (cfm) 100 Recirculation rate during isolation (cfm) 2,000 Rec!rculation rate postisolation (cfm) 1,900 Charcoal filter efficiency (methyl and elemental %)

95 HEPA filter efficiency (%)

95 O

Factors

-)

ccuoancy (92 2.2.T 6112. >

Time Period Factor 0-8 hr 1,0 h 44 8-24 hr 0.5 24-96 hr O.6 96 720 h-0.4 yt 9

97-4 T.

l t

L

. isse-21.ues 1 of 1 March 199E

(. -

Le

TD r1Q4CO 1

I INSERT I Leakage values based on double damper closure e

3HVV-FNI A/B,3HVR-FN5 and 3HVR-FN7 trip upon receipt of an SIS signal.

e 3HVQ-FN2 is secured locally at I hour 20 minu'.es post-LOCA.

Ventilation and Leakage Parameters Ventilation and Leakatse Parameters T=0 hrs to T=30 days Post-LOCA Ground Level Release cfm 3HVQ-FN2 (ESF bldg normal exhaust) Note 1 55 N u f/3/0 3HVQ*ACUSl A&B (ESF bldg AC) 4 3HVQ* ACUS 2A&B (ESF bldg AC) 2 Unit 1 Stack 3GWS-FN1 A&B (Process Vent Fan) 50 (Aux 66'-6")

3HVR*FN12A&B (SLCRS exhaust - duct leakage) 63 (Aux 66'-ti")

Ventilation Vent 3HVR-FN8A&B (Waste Disposal blog normal exhaust) 43 (Aux bldg 66'-6")

3HVR-FN9 (Fuel bldg exhaust - duct leakage) 75 (Aux bldg 66'-6")

3HVR*FN6A&B (Aux bldg filter exhaust) 17 (Aux bldg 66'-6")

3HVR* AOD44 A&B (Normal exhaust isol) 80 (Aux bldg 24'-6")

3HVR*AOD32A&B (Containment purge exk!!st) 118 (Aux bldg 24'-6")

Note 1: This fan is secured locally st I hr 20 minutes post-LOCA

l l

m k h - F8J-/OD MNPS-3 FSAR TABLE 15.6-22 TECHNICAL GUPPORT CENTER 30-DAY INTEGRATED DOSE 1

Thyroid Wh' ole Body Beta Dose Gamma Dose "

~ "~ Skin Dose ~'

Event kaml (rem)

(rem) fip Ur.it 3 LOCA F.*c t vv;-

J. '. J7 N

3 3M+M tBE+oo 2.B E + o l

. (H.-21' 6iM.,

Main:

3.8 38

1. M. E + 00 = h4 X 10 c-ho

2. The curr T3C LOCA analysis result in a thyroid dose of,5ffE+00, a whole body gamma dose

+00 and a beta skin dose of 1.4E+01. The current results are bounded by th 9,g license umbers listed in the table.

i

/a/f

,,c 6

• m' e, dro3wres 199 1

u.r.c, n u,.!,

1 of 1

WS P3 -100 MNPS-3 FSAR APPENDIX 15A DOSE METHODOLOGY o.n o y

The radiological consequences of design-basis accidents are quantified in terms of thyroid doses and whole-body gamma doses at the exclusion area boundary (EAB)f5TYhe low

',t 7"484 37 population zone (LPZ). The doses at the EAB are based upon releases of radionuclides over a period of two hours following the occurrence of an assumed accident: those at the LPZ are based upon releases over a thirty-day period following tF3 occurrence of this accident.

Thyroid doses for the nontevised accidents are calculated based upon Equation 15A-1:

17 44.

Dmy =

(A) (X/d (B.R.) (Cy (15A-1) where:

thyrcid dose (rem)

D

=

activity of iodine isotope i released (curies)

A,

=

X/a atmospheric dispersion factor (sec/ meter )

8

=

breathing rate (meter'/sec)

B.R.

=

and C%

thyroid dose conversions factor (rem /ci)

=

(Reg. Guide 1.109,1977)

The X/Q values presented in Table 15.0-11 were calculated using the methodology de-scried in FIAR Section 2.3.4.

I lodine nuclide contribution to tne external whole body gamma dose for the nontevised UN accidents is calculated using Equation 15A-2 (derived from equations in Regulatory Guide 1.4,1974):

Dr = 0.26 A,Ki(X/Q 17'* 4 (15A-2) where:

D, gamma dose t from a semi-infinite cloud (rem)

=

l AM*

E,.

average gemma energy per disintegration of isotope (MeV/ dis) t-Mas, 1

=

[

/G A

activity of isotope o,ver the given time interval (curies)

=

i l -g t rdeGed and X/O = atmospheric dispersion factor (sec/ar) g.u A ma APM sA.wa 15A-1 March 1998 i

2

._--____,____-0

y h$ f ] */C O MNPS-3 FSAR Foe. &c. v.> awl ucJ%b, 4 g g g.,

, _ g g g, g e g g,1c.,e,g,er a Cdc.

' Sm.hr u -

g p h q g e f a e, % e a m q d g Q m T,A-p 3 % g g Dose facters bN, egu atory Guide 1.109 Revision 1 are used to calculate potential annual noble gas gamma whole body. le&c dere 'rrte'r '^' t'e "c9 red ac;M;c.a are frac. :C' 30. The equation from Regulatory Guide 1.109 is as follows:

D, = 3.17 X 10' (O) (X/0) (DF/)

(15A-3) where:

annual noble gas gamma whole body dose (mrem)

D[

=

release rate of radionuclides i (Ci/ year)

Q

=

8 X/0 atmospheric dispersion factor (sec/ meter )

=

gamma whole body dose factor for a uniform semi-infinite cloud of DF(

=

radionuclides i mrem-m*

q,. g pCi-year The constant 3.17 x 10'is in units of oCi vear Ci-sec 4.ch.ed Dose contributions from the iodine and noble gas are added to obtain the net gamma whole O m l body dose.

The following is a list of computer programs which are used to calculate design-basis u.w source terms and radiological consequences of the nonrevised design basis accidents in FSAR Chapter 15:

1.

ACTIVITY 2 Program ACTIVITY 2 calculates the concentration of fission products in the fuel, coolant, waste gas decay tanks, ion exchangers, miscellaneous tanks, and release lines to the atmosphere for a PWR system. The program uses a l

library of properties of more than 100 significant fission products and may be modified to include as many as 200 isotopes. The output of ACTIVITY 2

{

presents the isotopic activity and energy spectrum at the selected part of the j

system for a given operating time.

2.

RADIOISOTOPE Program RADIOISOTOPE calculates the activity of isotopes in a closed system by solving the appropriate decay equations. Based on the activity of any isotope in the system at an initial time, the program calculates the activity of that isotope and its offspring at any later time, provided that the decay scheme is contained in the program library. Furthermore, because gamma activity is important for dose rate and shielding calculations, RADIOISOTOPE also calculates the energy releases in seven gamma energy groups from the decay of an inventory or radionuclides.

Am 6A.MP3 15A-2 March 1998

9 P ' S/*3 -/00 MNPS-3 FSAR

}

.7.

TACT 111 l

The TACT lli computer code simulates the movement of radioactivity released from a reactor core as it migrates through user-defined regions (nodes) of the containment,is immobilized by filters and sprays, and leaks to the outside environment. A run of the code carries out the integration of equations over a succession of contiguous time intervals following reactor shutdown, with the interval boundaries corresponding to transitions of system parameter values. Outputs include the level of radioactivity in each D6 node of containment and in the environment, broken down as iodines, noble NW

_ gases and solids and the radiation dose at the exclusion radius and the boundary of the low population zone.

The basic formula of dose conversion used in TACT lli is the following:

E D,, = (DCF),, Bf X,, (t)dt

~

where:

D,,

= the dose (rem) to the thyroid, the beta dose (rem) to the whole body or the gamma dose (rem) to the whole body from nuclide n DCF

= the respective dose conversion factors

%c6 r B-

= the breathing rate for the referenced individual (thyroid only)

/2 y

X,, (t) = the air concentration of nuclide n over any appropriate period of time Reference' for Appendix 15A s

Regulatory Guide 1.109," Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10CFR Part 50, Appendix 1," Rev.1, Oct.1977.

Regulatory Guide 1.4, " Assumption Used for Evaluating the Potential Radiological Conse-quences of a Loss of Coolant Accident for Pressurized Water Reactor," Rev. 2, June 1974.

J l

AreisA.ws 15A-4 March 1998

_l-___l

)

.3-Qff - p f3 -/bD Insert J 8.

PERC 2 -

~ Program PERC 2 is identical to DRAGON 4 in terms of the environmental-transport and dose conversion, but it includes the following:

Provision of time-dependent releases from the reat.

.._.nt system to the containment atmosphere Provision for airborne radionuclides other than noble gas and iodine, including daughter in-growth Provision for calculating organ doses other than thyroid e

Provisions for tracking time-dependent inventories of all radionuclides in all control regions of the plant model Provision for calculating energies as well as activities for the e

inventoried radionuclides to permit direct equipment qualification and vital access assessment i

i l

l I

l I

l I

I c.;

1 J

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l Docket No. 50-423 I

i B17276' i

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Millstone Nuclear Power Station, Unit No. 3 Proposed License Amendment Request SLCRS Bypass Leakage (PLAR 3-98-5) i Description of the Change, Background and Safety Summary i

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.. I U.S.- Nuclear Rrgul: tory Commission B17276\\ Attachment 3\\Page 1 Backaround SLCRS is used to maintain the secondary containment under a negative pressure relative to atmospheric by collecting air from the enclosure building and the connecting ' areas, filtering it to remove lodines, and discharging to the atmosphere.

NNECO has identified potential release pathways from secondary containment to the environment which could bypass the SLCRS filter after a LOCA. Although the SLCRS boundary is isolated by redundant safety-related dampers after the safety injection signal (SIS), certain non-nuclear safety grade fans (NNS) within the SLCRS boundary may not trip and remain running if offsite power is j

available. Bypass to the environm9nt can occur through the closed boundary dampers if the supply fan HVQ-FN1 located in the Engineered Safeguards Features building trips but the exhaust fan 3HVQ-FN2 continues running. This scenario could create negative pressure in the fan suction duct work and force containment atmospheric effluent, leaked to the enclosure building, through the closed dampers to the vital areas.

The ESF supply fan receives trip signals from both trains of Safety injection logic and will trip because of the redundancy. The exhaust fan, however, receives only a single isolation SI signal to the NNS starter.

Subsequent review of the plant ventilation systems identified additional NNS fans whose operation after an accident may affect the analyzed doses to the' vital areas. These fans are identified below (the list includes fan 3HVQ-FN2 for completeness):

3HW-FN1 A and 1B (Main Steam Valve Building exhaust fans) 3HVR-FN5 and 7 (Auxiliary Euilding exhaust fans) l 3HVQ-FN2*

(ESF Building exhaust fan)

[* the fan does not receive a redundant trip signal frera SIS. The remaining four fans receive redundant trip signals upon SIS).

' These fans are not powered by vital power, so the scenarios evaluated assume

- that offsite power is available.

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. U.S. Nucl:ar Regul tory Commission o

. B17276\\ Attachment 3\\Page 2 The proposed FSAR revision addresses the changes needed to ensure that all five fans are secured within one hour and 20 minutes after an accident, prior to shifting the

- control room ventilation from pressurization to filtration mode.

Current Desian Control Room - two redundant systems provide ventilation to the control room envelope. The emergency ventilating filtration assembly consists of a moisture separator, electric heater, prefilter, upstream high-efficiency particulate air (HEPA) filter, charcoal adsorber, downstream HEPA filter, and associated duct work and fans. When the control room is isolated after a LOCA or high radiation alarm from intake monitors, or by manual action, the outdoor air and the exhaust air isolation butterfly valves close. The air-conditioning units serving the control room continue operating without outdoor air to maintain required humidity and temperature. Following a Control Building Isolation (CBI) signal, the control room is pressurized from one of two banks of air storage tanks to slightly above atmospheric.

After one hour, the operators change the alignment to filtration / recirculation mode of operation which requires opening air-operated outside air inlet dampers 3HVC*AOV25 and 26 to introduce 230 cfm of air and re-pressurize the control room envelope. The inlet dampers are fitted with hand-wheel operators to ensure their opening should the non-safety grade instrument air system not be available.

The positive pressure in the control room provides a continuous purge of the atmosphere and protects against infiltration of smoke or airborne radiation from the surrounding areas.

Technical Support Center (TSC) - the ventilation system consists of a split-system air conditioning unit, duct-mounted electric heating coil, motor-operated dampers,.and associated duct work and fans. The majority of air is recirculated and mixes with outside make-up air during normal operation.

Upon receipt of the CBI signal, motor-operated dampers modulate to their respective positions to allow for building isolation. The TSC charcoal filtration assembly' starts.to operate in a filtered recirculation mode (2,000 cfm of recirculated' air for 30 minutes). Upon isolation, the TSC remains isolated for 30 minutes with no ventilation intake and 2,000 cfm filtered recirculation.

l Ifhirty minutes after the building isolt thn signal, the solenoid-operated dampers modulate to provide 100 cfm outside air and 1,900 cfm recirculation air into the

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. U.S. Nuclear Regulttory Commission B17276%ttachment 3\\Page 3 charcoal filtration assembly which'is discharged to the intake of the air-conditioning unit. The system remains in this configuration for the remainder of the accident.

The original offsite dose calculations considered the impact of the potential BLCRS byptss leakage paths associated with the continued operation of the l

NNS fans. The containment leakage in these calculations was terminated one i

hour after the accident when the containment pressure was reduced to below

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atmospheric by the action of the Quench and Recirculation Spray systems. The offsite areas included the Exclusion Area Boundary and the Low Population Zone (EAB/LPZ). However, the original control room habitability analysis was developed without evaluating the impact of the additional bypass leakage from-the SLCRS. It was believed that thesc paths were not limiting with respect to the control room dose analysis because:

the NNS fans were assumed to isolate within 30 minutes following the LOCA, i

e thus terminating the bypass leakage the control room pressurization system would be in service for at least i hour i

e before filtered outside air would be introduced by re-alignment of the control room ventilation system in.1992, a major design change was implemented which changed the MP3 primary containment from sub-atmospheric to near-atmospheric design.

A calculation was performed to support the license amendment to eliminate the

- negative pressure design and revise the radiological doses in the EAB and LPZ.

To compensate for the fact that the post-LOCA containment leakage would exist for 30 days with the near-atmospheric containment, instead of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the following assumptions and input changes were made in the dose analysis:

the design containment leakage rate was changed from 0.9% per day to e

0.65% per day, credit was taken for iodine removal in the containment atmosphere by the e

. Quench and Recirculation Spray systems.

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As a result of this design change, significant revisions to the FSAR were also made. Part of the change included a revision to the Chapter 15 dose analysis description and results, inexplicably, the revision deleted the description and assumptions associated with the NNS fan discharge bypass pathways which were not evaluated in the new analysis. No specific reason or justification was a,

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. U.S. Nuclear Regulatory Commission B17276\\ Attachment 3\\Page 4 provided in the FSAR for the exclusion of the bypass paths discharging through the closed SLCRS boundary dampers from the dose source terms.

Description of the Chanae Recently, a new radiological dose analysis has been completed which included the source term from the bypass leakage. The analysis recalculated the doses to the EAB and LPZ populations, as well as to the Control Room and TSC vital areas. Three separate leakage scenerios were developed and analyzed, as described below-Bvoass Leakaoe for the EAB/LPZ Dose Analysis For this case, NNS fans discharging from the secondary containment are assumed to continue operating, with leakage through associated boundary dampers, for the entire 30 day dose analysis period. A limiting single failure of a complete train of ESF equipment to operate is postulated, which results in.only one of two redundant boundary dampers closing.

j Offsite power is assumed available throughout the accident.

Bvoass Leakaae for the Unit 3 Control Room Dose Analysis j

As in the LPZ/EAB case, a limiting single failure of a complete train of ESF equipment to operate is postulated.

Only one of the two redundant boundary dampers close. NNS fans continue to run for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and 20 minutes after the accident. At that time the five fan breakers are assumed tripped. At i hour and 40 minutes, the control room ventilation system is re-aligned to the filtered recirculation mode and the control room is repressurized.

Offsite power is assumed available throughout the

accident, i

Bvoass Leakaae for the TSC Dose Analvsis 1

4 For the TSC dose analysis, offsite power is assumed available and credit

.is taken for the'NNS fan trip circuits to operate as designed. This means that fans 3HW-FN1 A and B, 3HVR-FN5 and 7 will trip, but fan 3HVQ-FN2 will continue.to run until secured by an operator 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and 20 minutes after the accident. The basis for this assumption is that it is consistent with

.the design basis for the,TSC ventilation system, which is not a safety-

. grade system.- A reliability analysis of the NNS fan trip circuit components r

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I Y,. U.S. Nuclxr Regulatory Commission B17276%ttachment 3\\Page 5

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demonstrated that the reliability of the NNS fan trip circuits is equal to, or better than, the NNS TSC ventilation system components which are relied upon to provide a level of protection for accident mitigation and support j

personnel.

The FSAR will be revised to include a description of the additional bypass leakage. pcths and incorporate the consequent effects.

As part of these analyses, access to the fan motor and load control centers after an accident was j

l evaluated and documented.

Appropriate changes are being processed in i

accordance with plant procedures.

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SAFET(

SUMMARY

The addition of the dose from the potential SLCRS bypass leakage to the Design l

Basis LOCA and rod ejection analyses, and to the FSAR description, is l

determined to be an Unreviewed Safety Question. Previously, no leakage was assumed in the dose analysis for the Unit 3 control room and the Technical Support Center vital areas.

The change -is deemed safe because the radiological consequences remain bounded by the 10CFR100 and GDC 19 limits. The only increase in the calculated dose is to the TSC. The doses to the EAB, LPZ and the control room areas remain below the current licensing basis.

Operator action needs to be credited to ensure that all NNS fan breakers are tripped no later than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and 20 minutes after the accident.

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Docket No. 50-423 317276 1

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Millstone Nuclear Power Station, Unit No. 3 Proposed License Amendment Request SLCRS Bypass Leakage (PLAR 3-98-5)

Significant Hazards Consideration and Environmental Considerations l

l June 1998 s

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L d K O.S. Nucl:ar Regulatory Commission B17276%ttachment 4\\Page 1 l

Significant Hazards Consideration I

NNECO has reviewed the proposed revision in accordance with 10CFR50.92 and has concluded that the revision does not involve a significant hazards consideration (SHC).

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.The basis for this conclusien is that the three criteria of 10CFR50.92(c) are not j

l satisfied. The proposed revision does not involve a SHC because the revision would i

not:

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Involve a significant increase in the probability or consequences of an accident previously evaluated.

The potential condition of radioactive effluent bypassing the isolated boundary in the Supplemental Leak Collection and Release System after an accident cannot contribute to the probability of an accident previously evaluated. The leakage is caused by a postulated failure of the non-nuclear safety grade exhaust fans within the SLCRS boundary to trip after a safety injection signal. Operator action is needed to verify that the fans in question are tripped within a predetermined time delay after the accident in order that credit can be taken in the radiological dose analysis for the isolation of this source.

l The proposed operator action will verify that the power to the fan motors is terminated, which cannot create any conditions leading to a new accident. The verification will augment the procedure to minimize the consequences of the accident itself. The trip circuits of the fan motors do not interface with safety systems.

The consequences of the limiting design basis accidents have been evaluated with the additional bypass leakage. The doses for the Exclusion Area Soundary, j

Low Population Zone and Unit 3 Control room remain below the previously 1

calculated and approved licensing values.

The calculated doses for the Technical Support Center are higher than previously approved, but below the radiological acceptance criteria of GDC 19.

Therefore, the proposed license amendment does not involve a significant increase in the probability or consequence of an accident previously evaluated.

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. Create the possibility of a new or different kind of accident from any accident previously' evaluated.

-There are no conceivable conditions, created by the proposed operator action, that may lead to the possibility of a new accident. Interruption of power to the exhaust fans is, in.itself, a part of accident mitigating activity. The proposed J

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[. " -, U.S. Nuclear Regulatory Commiss' ion B17276\\ Attachment 4\\Page 2 activity cannot create an adverse environment where a possibility of'a new accident has to be considered.

The breakers used to de-energize the fans, control only the fan motors and no other equipment.

Clear labeling - ensures that no safety equipment is inadvertently de-activated. The revised ventilation system operating procedure will clearly specify the order of steps and confirmatory indicators necessary for safe shutdown of the exhaust fans. The equipment operator will be briefed before proceeding to open the breakers to the affected fan motors. To minimize the possibility of an error, this step will be done early in the sequence of procedural steps performed to re-align the control room ventilation system to the filtration / recirculation mode of operation after an accident.

Therefore, the proposed license amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.

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Involve a significant reduction in a margin of safety.

In considering the impact of the proposed revision on the margin of safety, as defined in the Technical Specifications, the impact on the design basis analysis of the fission product barriers must be evaluated, i

The proposed operator action to trip the fans is done as part of personnel protective actions after a major accident, which is to stop the distribution of 1

radioactive iodine into the vital areas through the ventilation system within a l

predetermined time. The maintenance of the fission product barriers is no.

. affected by this action. This potential source of radioactivity associated with the ventilation fans discharging through the closed SLCRS boundary dampers has not been considered previously in the dose analysis, including this source results in a small increase in the gamma and beta doses to the Technical Support Center. The GDC 19 limits for protection of personnel in the vital areas however, are not violated. The calculated doses to EAB/LPZ zones and to the control room vital area remain below the current licensing base values.

1 Therefore, the proposed license amendment request does not involve - a significant reduction in the margin of safety, in conclusion, based on the information provided, it is determined that the proposed

- revision does not involve an SHC.

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a 4 U.S. Nucl:ar Regul tory Commission B17276%ttachment 4\\Page 3 Environmental Considerations NNECO has reviewed the proposed license amendment against the criteria of 10CFR51.22 for environmental considerations. The proposed revision does not involve i

an SHC, does not significantly increase the type and amounts of effluents that may be released offsite, nor significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, NNECO concludes that the proposed revision meets the criteria delineated in 10CFR51.22(c)(S) for categorical exclusion from the requirements for environmental review.

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