ML20079B003

Proposed Tech Spec 4.6.4.2.b.4 Re Hydrogen Recombiners

ML20079B003
Person / Time
Site:	Millstone
Issue date:	06/06/1991
From:	NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20079B000	List: B13834, Application for Amend 47 to License NPF-49,modifying Tech Spec 4.6.4.2.b.4, Electric Hydrogen Recombiners, to Provide Variable Acceptance Criteria for Flow Testing Containment Pressures ML20079B003
References
NUDOCS 9106120198
Download: ML20079B003 (9)

Text

. - . . . - -- - - - - - - - _ - . - - - . - - - - - - . - . - - - - - . - - -

4 L

Qqqket No. 50-42]

B13834 Attachment 1 Millstone Nuclear Power Station, Unit No. 3 Proposed Technical Specification Change Hydrogen Recombiners June 1991 9106120193 910606 PDR ADOCK 05000423 P POR

INDEX LlHITING CONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS SLCT10N EiG1 Air Temperature................................... 3/4 6 9 Containment Structural Integrity.................. 3/4 6-10 Containment Ventilation System.................... 3/4 6 11 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS Containment Quench Spray System........ ........... 3/4 6-12 Recirculation Spray System......................... 3/4 6-13 Spray Additive System.............................. 3/4 6-14 l

l 3/4.6.3 CONTAINMENT ISOLATION VALVES....................... 3/4 6-15 3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Monitors.................................. 3/4 6-35 Electric Hydrogen Recombiners...................... 3/4 6-36 3/4.6.5 SUBATHOSPHERIC PRESSURE CONTROL SYSTEM Steam Jet Air Ejector.............................. 3/4 6-37 3/4.6.6 SECONDARY CONTAINMENT Supplementary Leak Collection and Release System... 3/4 6-38 Enclosure Building Integrity. . . . . . . . . . . . . . . . . . . . . . . 3/4 6-40 Enclosure Building Structural Integrity. . . . . . . . . . . . 3/4 6-41 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE S a f e ty V a l v e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3/4 7-1 TABLE 3./-l MAXIMUM ALLOWABLE POWER RANGE NEUTRON FLUX HIGH SETPOINT WITH INCPERABLE STEAM LINE SAFETY VALVES DURING FOUR LOOP 0PERATION......................... 3/4 7-2 TABLE 3.7-2 MAXIMUM ALLOWABLE POWER RANGE NEUTRON FLUX HIGH SETPOINT WITH INOPERABLE STEAM LINE SAFETY VALVES THREE LOOP OPERAT10N............................ .

3/4 7-2 MILLSTONE - l' NIT 3 ix Amendment No. E9 0043

i

\

[QNTAINMENT SYSTEMS ELECTRIC HYDR 0 GEN RECOMBINERS LIMITING CONDITION FOR OPERATION 3.6.4.2 Two independent Hydrogen Recombiner Systems shall be OPERABLE.

APPLICABILITY: MODES 1 and 2.

ACTION:

With one Hydrogen Recombiner System inoperable, restore the inoperable system to OPERABLE status within 30 days or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SVRVEllLANCE RE0VIREMENTS 4.6.4.2 Each Hydrogen Recombiner System shall be demonstrated OPERABLE:

c. At least once per 6 months by verifying during a Hydrogen Recombiner System functional test that the minimum reaction chamber gas temperature increases to grcater than or equal to 700*F within 90 minutes and is maintained for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and that the purge blower operates for 15 minutes,

b. At least once per 18 months by:

1) Performing a CHANNEL CALIBP.ATION of all recombiner instrumentation and control circuits,

2) Verifying through a visual examination that there is no evidence of abnormal conditions within the recombiner enclosure (i.e., loose wiring or structural connections, deposits of foreign materials, etc.),

3) Verifying the integrity of all heater electrical circuits by performing a resistance to ground test following the above required functional test. The resistance to ground for any heater phase shall be greater than 10,000 ohms, and

4) Verifying during a recombiner system functional test using containment atmospheric air at an acceptable flow rate as determined in Section 4.6.4.2.b.5 that the gas temperature increases to greater than or equal to 1100*F within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and is maintained for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

l

5) Verifying during a recombiner system functional test using containment atmospheric air that the blower would be capable of delivering at least 41.52 scfm at containment conditions of 12.47 psia and 130*F.

l MILLSTONE - UNIT 3 3/4 6-36 Amendment No. f7 l 0045 l

This page intentionally left bli.nk MILLSTONE - llNIT 3 3/4 6-36a Amendment No. f/, %J 0045

CONTAINMENT SYSTEMS BASES 3/4.6.3 CONTAINMENT ISOLATION VALVES The OPERABILITY of the containment isolation valves ensures that the containment atmosphere will be isolated from the outside environment in the event of a release of radioactive material to the containment atmosphere or pressurization of the containment and is consistent with the requirements of General Design Criteria 54 through 57 of Appendix A to 10 CFR Part 50.

Containment isolation within the time limits specified for these isolation valves designed to close automatically ensures that the release of radioactive material to the environment will be consistent with the assumptions used in the analyses for a LOCA. FSAR Table 6.2-65 lists all containment isolation valves. The addition of deletion of any containment isolation valve shall be made in accordance with Section 50.59 of 10CFR50 and approved by the Plant Operation Review Committee.

3/4.6.4 COMBUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be available to maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions. Either recombiner unit or the Mechanical Vacuum Pumps are capable of controlling the expected hydrogen generation associated with: (1) zirconium-water rehetions, (2) radiolytic decomposition of water, and (3) corrosion of metals within containment. These Hydrogen Control Systems are consistent with the recommendations of Regulatory Guide 1.7, " Control of Combur.tible Gas Concentrations in Containment Following a LOCA," March 1971.

The Post-LOCA performance of the hydrogen recombiner blowers is based on a series of equations supplied by the blower manufactuer. These equations are also the basis of the acceptance criteria used in the surveillance procedure.

The performance was based on starting containment conditions before the LOCA of 10.59 psia (total pressure),120'F and 100% relative humidiy.

The acceptance flow rate is the rcquired flow rate at the worst case containment conditions 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the LOCA. The analysis assumes the recombiners are started no later than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the accident. The 18-month surveillance shall verify the gas temperature and blower flow rate concurrently.

3/4.6.5 SUBATMOSPHERIC PRESSURE CONTROL SYSTEM 3/4.6.5.1 STEAM JET AIR EJECTOR The closure of the isolation valves in the suction of the steam jet air ejector ensures that: (1) the containment internal pressure may be maintained within its operation limits by the mechanical vacuum pumps, and (2) the containment atmosphere is isolated from the outside environment in the event of a LOCA. These valves are required to be closed for containment isolation.

MILLSTONE - UNIT 3 83/46-3 Amendment No. /E 0046

. _ . = . . - . - _ - = - . - - - . . _ - _ _ _ _ . _ - - - _ - . .

Qocket No. 50-423 813834 Attachment 2 Millstone Nuclear Power Station, Unit No. 3 Hydrogen Recombiner Blower Equations l

l l

l l June 1991 l

l l . .. _

1 l

Millstone Nuclear Power Station, Unit Nn. 3 Hydroaen Recombiner Blower Ecuations Iest hethod

1. Measure and record the following information:

Pcontainment--Average of 3LMS*P934, 935, 936, and 937 Pout--From 3HCS-PIIA or B Tc- Containment temperature Pin--Measure with a new inlet gauge or calculate from Equation 2a below scfm measured--See Procedure / Form 3613A.3-1 APf --From Table 2 (attached)

A--Slip Constant

2. Equations to calculate as found slip constant (A)

a. Pin - Pcontainment - AP 7

b. Effective Pressure Rise EPR EPR -

• 14.7 - 14.7

c. Gas Slip Correction Factor (GSCF)

GSCF - I4*7

• Tc + 46Q 'b

, Pin 528

d. Slip RPM

- A * (EPR)k

• GSCF

e. Actual Inlet CFM ACFM = .028 (3550 RPM - Slip RPM)

f. Standard CFM scfm-ACFMk7 Tc 60

g. Adjusted Flow Rate scfm adjusted - (scfm

• 0.95) should equal (scfm-measured accuracy range)

4

h. A is calculated by substituting the above equations into g

- scfm measuridAccuracy -

3550 - Tc + 460 '

, lid.

0.028

• 0.95 .

Pin 528 ,,

A=

l Equi , 14.7 ' - 14.7'% , ' Ji l , Tc + 460 '%

Pin . .

, Pin 528 ,

3. Equations to calculate postaccident flow rate using A calculated in Step 2.

a. Effective Pressure Rise EPR EPR - 4.937

b. Gas Slip Correction Factor (GSCF)

GSCF = 1.218 I

c. Slip RPM  ;

= A * (EPR)5

• GSCF

d. Actual Inlet CFM ACFM .028 (3550 RPM - Slip RPM)

e. Standard CFM scfm - ACFM 0.725

f. Postaccident scfm Minimum - scfm

• 0.95

g. Acceptance Flow Rate Postaccident scfm minimum 2 41.52 scfm.

i

Table 1 Accuracy Range (Ref. 2) scfm (measured) Accuracy Ranae 40 to 50 5.8 sct'm 50 to 80 4.7 scfm Table 2 Inlet Piping loss scfm Heasured AP7 (psi)

(Unad.iusted) 30 .21 40 .31 50 .52 60 .73 70 .98 80 1.28

References:

1. Calculation 90-RPS-722GM " Flow Acceptance Criteria for 3HCS*RBNR 1 A/B Blowers 3H:S*CI A/B."

2. Calculation PA 90-L0E-6132GE, " Hydrogen Recombiner Flow Error Analysis."

I l

l I

l

_ _ _ _ _ _ _ _ _ _ _ _