ML19354E116

Provides Revised Info Documenting Util long-term Resolution Hydrogen Monitoring Capabilities & Requesting Relief from NUREG-0737,Item II.F.1 Requirements

ML19354E116
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/09/1990
From:	James Fisicaro ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19354E113	List: ML19354E112 ML19354E116
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.1, TASK-TM 0CAN019008, CAN19008, NUDOCS 9001250422
Download: ML19354E116 (5)

Text

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• ARKANSAS POWER & LIGHT COMPANY l

i i

l January 9,1990 OCAN019008 '

t U.-S. Nuclear Regulatory Commission  !

Document Control Desk '

Mail Station P1-137  !

Washington, DC 20555 l

Subject:

Arkansas Nuclear One - Units 1 & 2 Docket Nos. 50-313 and 50-368 i License Nos. DPR-51 and NPF-6 '

Long Term Hydrogen Monitoring Capabilities.

and Relief Request t

i Gentlemen:

The purpose of this letter is to document Arkansas Power and Light's (AP&L) long-term resolution to the Hydrogen Monitoring Capabilities on Arkansas  :

Nuclear One, Unit 2, and to request relief from a specific requirement of NUREG 0737 for Unit I and Unit 2. This request has been discussed with Mr. Chester Posiusny, ANO-2 NRR Project Manager on several occasions. In our letter of August 25, 1989 (2CAN088914), on Hydrogen Monitoring Capabilities - Request for Waiver of Compliance, AP&L provided a short-term resolution to Hydrogen Monitoring System design and procedural. deficiencies i and requested a waiver from the 30 minute time requirement of NUREG-0737,  !

Item II.F.1, Attachment 6. In your letter of-August:30, 1989 )

(2CNA088907), on Hydrogen Monitoring Capabilities Waiver of Compliance, '

you stated your concurrence with AP&L's short-term resolution. To address -i l

the long-term issue of Hydrogen Monitoring on ANO-2, AP&L has completed the '

below described design changes (per the attached' drawing) and procedure revisions. '

The design deficiency described in 2CAN088914 and 2CAN098902 pertained to '

our failure to meet the single failure criteria for the ANO-2 Hydrogen l Analyzers. Specifically, AP&L determined that a specific set of. assumed events could lead to a loss of immediate monitoring capability. The loss

• could occur as a result of failure of the " red" power source following y successful containment. isolation but prior to initiation of monitoring.

Since the " green" channel hydrogen analyzer return-line isolation valve-

{

(inside containment motor operated valve) was powered-from the red channel, and failed as is, the failure of the red power supply could preclude hydrogen monitoring. To resolve the design deficiency, AP&L has completed design changes to provide a fail open solenoid operated valve (S0V)-in place 7

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l U. S. NRC Page 2  ;

January 9,1990  ;

t oftheMOVinthereturnlineofthe" green"channelhydrogenanalyzer. As i a result, loss of " red" power will'not preclude operation of this green" train analyzer.- Containment isolation in this event would be accomplished i via the redundant " green" SOV. A drawing of the arrangement prior to.and l

following the modification is attached.  ;

Since correcting the design deficiency AP&L has concentrated its efforts on l reducing the time required to place the hydrogen analyzer in service post LOCA. These efforts have been focused on improvement to the hydrogen monitoring equipment and emergency operating procedures. During. testing  :

associated with the installation of the above described design change, a low ,

flow condition was identified on the green channel hydrogen sample pump. To -

minimize sample transport tiine between the dome of the containment and the analyzers (located in the Auxiliary Building), AP&L has purchased a replacement sample pump. The new pump has been received on site and installation was begun on January 8,1990, and is expected to be completed by January 12, 1990. This new pump should decrease the transport time of the sample from approximately 55 minutes to 15 minutes. Post modification testing will be performed to verify this improved sample time. Transport time for the red channel pump was measured at approximately 20 minutes.  ;

AP&L has completed permanent procedure changes to address hydrogen monitoring. A step has been added to the ANO-2 Emergency Operating Procedure in the sequence of actions after a Safety Injection- Actuation Signal to initiate hydrogen monitoring within one hour following a loss of coolant accident. It is projected that this step would normally be completed within 30 minutes of a Safety Injection Actuation Signal, however, ,

other failures (such as loss of off-site power, failure of an Engineered Safeguards actuated component, or other unforeseen event) could complicate the sequence of actions such that the sample might not be obtained for up to one hour and 30 minutes. Considering one hour from the onset of the LOCA to the initiation of hydrogen sampling and 30 minutes for system alignment and time to obtain a representative sample of the containment dome (with .:'

replacement of degraded pump) hydrogen analysis will be available within one hour and 30 minutes following a LOCA. After initial alignment, no' further local action is required to secure or restart-sampling. Although this is greater than the 30 minute requirement of NUREG-0737, Item II.F.1, Attachment 6, Containment Hydrogen Monitor, AP&L considers this to be'an acceptable time for the following reasons:

1. Based on Figure No. 6.2-25 of the ANO-2 Safety Analysis Report, it will take approximately 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> before hydrogen concentration in containment will reach 3% by volume. This assumes conservative hydrogen generation rates based on 10CFR50.44. Therefore, one and one-half hours provides ample time to start hydrogen monitoring.

2. This time is less than that recommended in NUREG-0737, Item II.B.3, Post-Accident Sampling Capability, which requires one hour to obtain a hydrogen s'imple (within the capabilities of our system) and a combined time of three hours or less for sampling and analysis.

j U. S. NRC Page 3 'i January 9,1990

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t To ensure prompt operator actions once dispatched to initiate hydrogen monitor AP&L plans to include in the upcoming training cycle instructions on ,

the hydrogen monitor system and its operation. Additionally, simulator scenarios will be conducted to verify the required actions can be completed  !

in the time frames discussed above. If from these exercises, we determine the above timeframes are not representative, additional action will be taken  !

to assure the analyzers are operable with one hour and 30 minutes. We will i inform the NRC of any such additional actions. .

We have also assessed the capability of the ANO-1 hydrogen analyzer.

Similar problems in regard to Hydrogen Sampling also exist for AND Unit 1.

The ANO-1 system does not meet the single failure criteria as described for .

ANO-2. A single failure of the '.' red" power source following successful  ;

containment isolation prior to initiation of monitoring would preclude obtaining hydrogen sample until the red power source can be restored, as -

stated in 2CAN098902. Although not'outside the design basis for ANO Unit 1, a design change has been scheduled during the next refueling outage to improve the overall reliability of the hydrogen analyzer system and correct this deficiency.

With respect to sample time, design changes were completed in 1987 to decrease the sample transport time such that a sample could be obtained within approximately 15 minutes from initiation of sampling with the intent 1 of ensuring Unit 1 met the 30 minute time requirement.. Testing of system  ;

performance will be performed during the next refueling outage to ensure the '

sample times are still as designed.

No local manual actions are required on ANO-1 to place'the system in service, however required actions performed on the control room back panels could be delayed by other failures similar to those described for ANO-2.

The appropriate step to initiate sampling is in such a sequence in the Emergency Operating procedure to require initiation of sampling within 30 minutes following a Safety Injection Actuation under : scenario with no other failures; however other failures could extend this time. Therefore, '

the 30 minute criteria of NUREG 0737, Item II.F.1 cannot be met for ANO-1.

Thus, a relief is also requested for ANO-1 to change the requirement for Hydrogen Sampling to within one hour and 30 minutes. Simulator scenarios to ,

verify actions can be performed in the required amount of time under varying +

accident conditions and operator training.as required will also be conducted for ANO-1. These actions will be completed within the next 90 days. Should we be unable to reasonably establish hydrogen monitoring within one hour and 30 minutes, we will inform the NRC of the resolution of any issues involved.

}

t

d

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.' l U. S. NRC Page 4 January 9, 1990- 1 It is requested _that documentation of your review of this request be '

provided to AP&L. Should you or your staff have ary questions concerning -

this resolution, do not hesitate to call.

.Very truly yours,  ;

e fbA >

James-J. Fisicaro a Manager, Licensing '

JJF/ CWT /1g Attachment i '

cc: Mr. Robert Martin U. S. -Nuclear Regulatory Commission '

Region IV

• 611 Ryan Plaza Drive, Suite 1000 .

Arlington,- TX 76011 NRC Senior Resident Inspector Arkansas Nuclear One -i ANO-1 & 2

-Number 1, Nuclear Plant Road -

Russellville, AR.72801~

Mr.-C. Craig Harback NRR Project Manager, Region ~IV/AN0-1 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-D-18 One White Flint North ,

11555 Rockville Pike . .

Rockville, Maryland 20852 Mr. Chester Poslusny NRR Project Manager, Region IV/ANO-2 U. S. Nuclear Regulatory Commission .

NRR Mail Stop-13-D-18~

One White Flint North .

11555 Rockville Pike '

Rockville, Maryland 20852 ANO-DCC File-1

3 i

i i AT,TACHMENT TO ANO-2 i ACAN019014 HYDROGEN MONITOR ARRANGEMENT ,

l r

1 BEFORE MODIFICATION 2SV4261-2 2CV4259-1 G G s

__ X @R '

X_g S_

XeC XF4i +

1 H2 MONITOR CAMS G '!

2SV4263-2 2SV-8265-1 -

_G _G _R S S S -

S -- --

X X X -

+- .

.FC FO- -

AFTER MODIFICATION-a l MODIFIED

. 2SV4261-2 MV-8259-1 f G _ G __ R VALVE t

S S S  :!

5k _ XFC 4 5A +

~

S FO H2 MONITOR CAMS '

G 2SV4263-2 2SV-82651-- ,

G G R S S S -

S -

X XFC XFO ~+

j-4 '

G GREEN POWER FO FAIL OPEN FAI FAIL AS IS -

j-. R RED POWER FC Fall CLOSED pr-* e =w m-,e- e-A. , m .-<-n* *es .--_____-_.s. am._ ___-__m s --a-,u m--_____m