ML20042F754

Proposed Tech Specs Re Surveillance Requirements for Control Room Emergency Filtration Sys

ML20042F754
Person / Time
Site:	Grand Gulf
Issue date:	05/07/1990
From:	SYSTEM ENERGY RESOURCES, INC.
To:
Shared Package
ML20042F752	List: ML20042F751 ML20042F754
References
NUDOCS 9005090351
Download: ML20042F754 (5)

Text

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SURVEILLANCE REQUIREMENTS (Continued) .

L l 2. Verifying that the subsystem satisfies the in place testing I L

acceptance criteria and uses the test procedures of Regulatory Positions C.S.a, C.5.c and C.S.d of Regulatory Guide 1.52 Revision 2, March 1978, and the system flow rate is 4000 cfm.

• 10%.

3. Verifying within 31 days after removal that a laboratory analysis of a representative carbon sample obtained in accordance with.

Regulatory Position C.6.b of Regulatory Guide _1.52 Revision 2, March 1978, meets the laboratory testing criteria of' Regulatory Position C.6.a of Regulatory Guide 1.52 Revision 2, March 1978.

4. Verifying'a subsystem flow rate of 4000 cfm t 10%'during subsystem operation when tested in accordance with ANSI N510-1975.

c. After every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation by verifying within 31 days after removal that a laboratory analysis of a repre-sentative carbon sample obtained in accordance with Regulatory Positon C.6.b of Regulatory Guide 1.52 . Revision 2, March 1978, meets the laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 2, March 1978,

d. At least once per 18 months by:

1. Verifying that the pressure drop across the combined HEPA filters and charcoal adsorber banks is less than 7.2 inches Water Gauge while operating the subsystem at a flow rate of 4000 cfm i 10%.

2. Verifying that the subsystem receives an appropriate isolation actuation signal by each of the following test conditions.. For at least one of the test conditions, verify that the subsystem

automatically switches to the isolation mode of operation and 3 .theisolationvalvesYclosewithin4 seconds

l O (a) High high radiation in the outside air intake duct.

(b). High drywell pressure, (c) Low low reactor vster level, and (d) Manual initiation from the Control Room.

3. Verifying that the heaters dissipate 20.7 1 2.1 kW when tested in accordance with ANSI N510-1975 (except for the phase balance criteria stated in Section 14.2.3),

e. After each complete or partial replacement of a HEPA filter bank by verifying that the HEPA filter banks remove greater than or equal to 99.95% of the 00P when they are tested in place in accordance with ANSI N510-1975 while operating the system at a flow rate of 4000 cfm i 10%..

f.' After each complete or partial replacement of a charcoal adscrber bank by verifying that the charcoal adsorbers remove 99.95% of a halogenated hydrocarbon refrigerant test gas when they are tested in place in accordance with ANSI N510-1975 while operating the system at a flow rate of 4000 cfm.1 10%.

GRAND GULF-UNIT 1 3/4 7-6 Amendment No. 25j ho 2351 900507 P OCK 05000416 PDC

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'NL-90/04 INSERT TO TS 4.7.2.d.2~

(Z51-F001, Z51-F002, Z51-F003, Z51-F004, 251-F010 and 251-F011) g-

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-l A9004181/SNLICFLR - 15 o

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y ' Attachment 3 to AECM-90/0074 j RESPONSE TO NRC CONCERNS On April 13,1990 a telephone conference was held between representatives of-System Energy Resources, Inc.= (SERI), the NRC Resident . Inspector and the NRC, '

Project Manager to discuss issues related-to the proposed Technical Specification (TS) changes. During the discussions, several concerns were expressed by.the NRC for which SERI agreed to provide response and additional

-information. Those concerns and the SERI responses are as follows: j Concern 1:.The Z51-F007 and 251-F016 control room boundary valves should have l their maximum closure times' listed in,the TS.  ;

Response: Valves Z51-F007 and Z51-F016 are the control room standby fresh air intake valves. Unlike the normally open intake and exhaust valves, .

the Z51-F007 and Z51-F016 valves are normally closed. They are-designed to be opened 10 minutes following an accident provided 7 outside air conditions allow.

The Z51-F007 and Z51-F016 valves have no analytical closing times

• and their closing times are not used in any dose. calculations. i Maximum closing times for these valves are determined by using previous valve closing test data obtained by using ASME Section XI -

criteria and are subject to change throughout the life of the plant in accordance with ASME Section XI program-requirements.

Therefore, based on the above, valves 251-F007 and Z51-F016 should not have their maximum closure times listed in the TS.

Concern 2: GGNS should periodically test the control room unfiltered inleakage .;

limit contained in Operating License Condition 2.C(38).

Response: Standard Review Plan (SRP) 6.4.1, " Control Room Habitability System", specifies in Section .III.3.d.(2) that the use of a control '

room infiltration rate that is based-on calculation is acceptable.

except in the case where an applicant has assumed exceptionally ' low rates of infiltration. In addition, the SRP states that if an. ,

applicant were to submit an analysis that showed a gross leakage rate of less than 0.06 volume changes per hour, the NRC would require that the gross leakage be verified by periodic tests as described in Regulatory Position C.5 of Regulatory Guide 1.95,

Protection of Nuclear Power Plant Control Room Operators Against-an Accidental Chlorine Release."

GGNS Operating License Condition 2.C(38) specifies that the allowable control room leak rate is not to exceed 590 cfm. GGNS UFSAR Table 15.6-13 lists the control room parameters used in the 1 post-LOCA control room personnel dose analysis. The actual amount of unfiltered control room inleakage assumed in the dose analysis is 760 cfm and, therefore, bounds the inleakage permitted by Operating License Condition 2.C(38).

A9004181/SNLICFLR - 11

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. ,. Attachment 3<to AECM-90/0074L i i

u The control room volume assumed'in the-dose' analysis is 165,000 '

cubic feet. The combination of the control room volume and  ;

unfiltered inleakage utilized in the post-LOCA ' dose- analysis 1 results in an air change per hour rate of 0.28. This represents a rate of infiltration of greater than 4 times that. threshold ,

specified by the SRP where periodic testing of envelope-integrity a is called for. The control room personnel dose for a design basis .;

analysis.LOCA as shown in UFSAR Table 15.6-14 satisfy-the '

. requirements of General Design Criterion 19 of 10CFR50 Appendix A.

And, as noted above, consistent with Condition 2.C(38), the _;

allowable. leak rate is controlled below the value used-for dose calculations, thus providing further margin from GDC 19 limits. 'i As discussed in GGNS VFSAR Section 6.4.5, a leakage test was performed prior to initial plant operations to verify the leakage

of the' control room envelope. In addition, work controls exist to -

adequately control the work performed on the control' room envelope. [

In summary, periodic testing of the control room inleakage limit is

not considered necessary-for the following reasons- <

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a. The actual infiltration rate used.in the dose calculations is considerably greater than the threshold established in the SRP 2 where periodic testing would be expected.  ;

b. Allowable unfiltered inleakage is limited'below the value assumed in the dose calculations. I

c. Administrative controls are in place to manage. work activities ,

performed on the control room envelope. i Concern 3: What is the dose consequence of opening the isolation mo'e d fresh air supply valves post LOCA?

Response: The System Operating Instruction for the control room HVAC system ,

provides details on when the system may be operated following a

-LOCA in the post-isolation fresh air' makeup mode (i.e., when oxygen or carbon dioxide levels are out of specification or as deemed necessary by the Shif t Superintendent). Procedural provisions ,

include the requirement for continuous radiological monitoring at the fresh air intake when the system is in the post-isolation fresh air makeup mode.- The control room is to be notified if any increase'in radiological levels occur so the system can be returned -i to the isolation mode of operation. Therefore, the dose consequences of using the post-isolation fresh air makeup mode is minimized by procedural controls and the fact that it is a filtered pathway.

Concern 4: Why does GGNS not use the pressurized isolation mode of control room HVAC instead of the isolation mode with limited makeup filtered air?

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' , , Attachment.3 to AECM-90/0074

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Response:, The GGNS control room HVAC system is designed to provide a suitable-

_ environment for both equipment and personnel during normal plant

, operation and post-accident. During normal operation outside air,

for venti _lation purposes, is introduced _into the control room.

Post-accident operation in the post-isolation fresh air makeup mode results in the control room being pressurized. This mode of operatien introduces air quantities into the control room HVAC system fn excess of the amount introduced during normal plant operation in~ order to rapidly replenish the control room environment. The control room HVAC unit is not designed to operate

'(/.." --continuously in the post-isolation fresh air makeup mode and maintain control room-design temperatures under worst case meteorological conditions.

Therefore, because the control room HVAC. system was designed for the isolation mode with limited makeup, that is the mode used.

A9004181/SNLICFLR - 13 p,

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