ML19318C716
| ML19318C716 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 06/10/1980 |
| From: | Trimble D ARKANSAS POWER & LIGHT CO. |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-80-05, IEB-80-5, NUDOCS 8007020201 | |
| Download: ML19318C716 (5) | |
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X NSIC ARKANSAS POWER & LIGHT COMPANY STATE POST OFFCE BOX 551 UTTLE ROCK. ARKANSAS 72203 (501) 371-4000 June 10, 1980 1-060-05 2-060-06 Mr. K. V. Seyfrit, Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011
Subject:
Arkansas Nuclear One - Units 1 and 2 Docket Nos. 50-313 and 50-368 License Nos. DPR-51 and NPF-6 IE Bulletin 80-05 (File:
1510.1,2.1510.1)
Gentlemen:
The following information is provided in response to IE Bulletin 80-05.
After receiving the subject Bulletin a complete review of all tanks which could be valved to contain primary system water and whose failure could j
result in a release of radioactivity, was conducted.
These tanks were ex-1 amined to ensure that: a) adequate vacuum protection is provided, or that cover gas could be admitted rapidly enough to compensate for maximum draw down;b) tanks located outside would have ade their associated vacuum protection devices; c)quate freeze protection for all vacuum protection de-vices are covered by a surveillance program; d) no explosive gas mix-tures are allowed to form. The results of the review are presented be-low.
A total of twelve tanks for Unit 1 were identified as being capable of being valved to contain primary system water (Attachment A).
(Tanks located inside of the Reactor Building were excluded.) Of these twelve tanks, nine are vented to the Gas Collection Header with no isolation valves. These nine tanks are considered to be protected from develop-ment of a vact.um condition. Two of the twelve tanks have vacuum breakers installed on them. The remaining tank is operated with hydrogen used as a cover gas. Calculations have shown for this tank that either of the two pressure control valves installed on the tank are capable of providing hydrogen at a flow rate greater than the maximum draw down for this tank.
8007020 Y ueveen y,oote scur-ur, aries eysreo
Mr. K. V. Seyfrit Juna 10, 1980 Two of the twelve tanks associated with Unit 1 are located outdoors.
Both of these tanks are protected by vacuum breakers and are heated per techni-cal specification requirements. The heating of these tanks is considered to be a protection against freezing for the tank as well as the vacuum breakers. However, to provide additional protection to the vacuum breakers additional heat tracing will be installed around the breakers themselves.
These vacuum breakers will also be scheduled for inspection.during each re-fueling outage.
The only tank associated with Unit 1 which could contain significant amounts of hydrogen is T-4, the Reactor Coolant Make-Up Tank. This tank is protec-ted against a vacuum condition through the automatic admission of hydrogen rather than a vacuum breaker which could admit air.
The hydrogen purity is monitored to preclude the formation of an explosive gas mixture.
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A total of fourteen tanks for Unit 2 were identified as being subject to re-view per the subject Bulletin (Attachment B). Of these, six are vented to the Gas Collection Header with no isolation valves and one is vented to the atmosphere without isolation valves. These tanks are considered to be pro-tected from the development of a vacuum condition. Two of the fourteen tanks are designed to withstand even a perfect vacuum. Another of the tanks is protected by a vacuum breaker. The remaining four tanks have been identi-fied as requiring some form of vacuum protection. The modifications to in-sure the protection of these four particular tanks are presently being engi-neered and should be installed by no later than the next refueling outage.
In the interim the operators have been informed that there is a potential for damage to the Boron Management Hold Up tanks resulting from misoperation of the system.
The Refueling Water Tank 2T-3 and the Sodium Hydroxide Addition Tank 2T-10 for Unit 2 are located outdoors. The Refueling Water Tank is protected by a vacuum breaker and the Sodium Hydroxide Addition Tank is protected by two 2" unisolable vents. Both of these tanks are heated per technical speci-fications. As was the case for Unit 1, to provide additional freeze protec-tion for the vacuum protection devices, additional heat tracing w)ill be pro-vided around these devices. The vacuum breaker on the RWT (2T-3, along with any other vacuum breakers which might be installed as a vacuum protec-tion device, will be scheduled for surveillance during each refueling out-age.
In addition, a platform is being provided to allow inspection of the vacuum breaker on the RWT during icing conditions.
The only tank associated with Unit 2 which could contain appreciable amounts of hydrogen is 2T-4, the Volume Control Tank.
Since hydrogen purity in the tank is monitored and the tank is protected from a vacuum by the admission of more hydrogen rather than the admission of air, the tank is ;6uidered to be protected against the danger of forming an explosive gas mixture.
Very truly yours, hdve/(
David C. Trimble
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Mr.!K. V. Seyfrit June 10, 1980 DCT/DEJ/ms Attachments cc: Mr. Victor Stello, Jr., Director Office of Inspection and Enforceeent U. S. Nuclear Regulatory Comission Washington, D. C. 20555
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ATTACHMENT A i
Equip.
No.
Description Oty.
Comments Borated Water T-3 Storace Tank 1
Tank has 8" vacuum breaker Sodium Hydroxide T-10 Storage Tank 1
Tank has 2" vacuum breaker Clean Waste T-12 Receiver Tank 4
Unisolable vent to Gas Collection Header Dirty Waste T-20 Drain Tank 1
Unisolable Vent to GCH Reactor Coolant Hydrogen cover gas capable of matching T-4 Make-Up Tank 1
max draw down Treated Waste T-16 Monitor Tank 2
Unisolable vent to GCH i
Filtered Waste T-21 Monitor Tank 1
Unisolable vent to GCM
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Aux. Bldg. Ecuip.
T-11 Drain Tank 1
Unisolable vent to GCH
ATTACHMENT B Equip.
No.
Description Qty.
Comments 2T-3 Refuelina Water Tank 1
Tank has 18" vent 2T-10 Sodium Hydroxide Tank 1
Tank has 2x2" vents Boron Management 2T-12 Hold Up Tanks a
DCP will install vacuum breaker 2T-20 Waste Tanks 2
Unisolable vents to GCH Tank is designed to 2T-4 Volume Control Tank I
withstand 15 psi external 2T-21 Waste Condensate Tanks 2
Unisolable vents to GCH Degasifier vacuum Tank is designed to 2T-99 Pump Sep. Tank 1
withstand 75 psi external Boric Acid 2T-69 Condensate Tanks 2
Unisolable vents to GCH f-i
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