ML19312C696
| ML19312C696 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/14/1977 |
| From: | Parker W DUKE POWER CO. |
| To: | Case E, Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7912190899 | |
| Download: ML19312C696 (3) | |
Text
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- ESCMtPTION ENCLCSU RE Re NRC ltr dtd 8-15-77..... furnishing info in support of their request for exemption from requirements of Appendix J which were submitted on 11-30-76 & 2-15-77............
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DUKE POWER COMPANY Powra Bett.o No 422 Socra Cucaca SrazzT. CnAnt.ortz. N. C. 2824a wi wee o. ** a a t a. s a.
September 14, 1977 SCE PAES, CENT YEk f 8**CN E* A# C A 7C4
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Mr. Edson G. Case, Acting Director
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-i l;;W2*"r.r,$377 Office of Nuclear Reactor Regulation 5
U. S. Nuclear Regulatory Commission Washington, D. C.
20555
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D Attention:
Mr. A. Schwencer, Chief a
N/
Operating Reactor Branch #1, g'
Reference:
Oconee Nuclear Station Docket Nos. 50-269, -270, ~287
Dear Sir:
Your letter of August 15, 1977 responded to our requests for exemption from the provisions of 10CFR50, Appendix J which were submitted on
. November 30, 1976 and February 15, 1977. The requested exemptions con-cern the testing of certain containment isolation valves and the per-sonnel and emergency airlocks, respectively.
You requested additional information with regard to the valve testing and stated that you considered that acceptable measures could be taken to meet NRC delineated guidelines for airlock testing.
The following information is provided in response to your request.
2 Your letter stated that testing of five penetrations in a direction opposite to their safety functions did not require an exemption since Appendix J allows for this testing. This is considered acceptable and our. request for exemption is rescinded for the following penetrations:
a.
Penetration No. 5 RB Normal Sump Drain Line b.
Penetration No. 7 RB Pump Seal Outlet Line I
c.
. Penetration No. 18' Quench Tank Vent Line d.
Penetration.No. 29 Quench Tank Drain Line e.
Penetration No. 54 Component Cooling Water Outlet Line p
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Mr. Edsin G. CSc2,' T ing Dir:cter
'T Pzga Two S:ptemb:r 14, 1977 In Item 1 of the attachment to your letter, justification was requested for not leak testing seven penetrations.
The valves in the systems at these penetrations are not capable of being tested in accordance with Appendix J since appropriate isolation valves and test connectionssere not designed into these systems. Additionally, the following justifica-tions are presented for each penetration:
Penetration Description Basis for Classification 43 A OTSG Drain Normal working pressure of this 4
B OTSG Drain system is well in excess of design maximum accident pressure. Also, the system is siismic category I designed.
47 RCP Seal Vents This system is open to the RB (unit #1 only) atmosphere during the integrated leak rate test (conducted approxi-mately every 3 years) and its leakage is considered as part of the overall leak rate.
53 N2 to Core Flood Normal working pressure of this Tanks system is well in excess of design maximum accident pressure. Also, the system is designed seismic category I.
59 Core Flood Tank Normal working pressure of this Sample and Drain system is well in excess of design maximum accident pressure. Also, l
the system is designed seismic category I.
55 Demineralized This system is open to the RB Water Supply atmosphere during the conduct of
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the Integrated Leak Rate Test conducted approximately every 3 f
years.
51 Leak Rate Test The penetration is tested during Valve the Integrated Leak Rate Test is considered part of the overall leak rate. At the conclusion of the test, it is shut and not opened again until J
the next leak rate test.
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, ing Dircctor Mr. Edsoa G. Coco, Pcga Thrca S:ptembsr 14, 1977 The Oconee design was completed and approved by the Connission prior to the issaance of 10CFR50, Appendix J and modifications to the station in order to fully meet'the regulations would require extensive backfitting.
It is considered that such modifications would not provide substantial, additional protection for the public health and safety or the common defense and security and are therefore not justifiable. We reiterate our requeet for exemption to Appendix J in this regard.
In Item 2 of the attachment to your letter, it was stated that Table 5-4 of the Oconee Nuclear Station FSAR listed twenty-three penetrations which were not listed in our submittal as requiring leak testing.
The follow-ing listing presents the penetration description and basis for not leak testing.
It is considered that leak testing of these penetrations is not necessary nor required by 10CFR50, Appendix J.
Penetration Description Basis for Classification Loop A, A2 Nozzle This penetration does not serve as 8
1 Warming Lines a post-LOCA Containment isolation function. The HP injection system upstream of penetration is considera-bly higher pressure than Containment, is filled with water, and meets seismic Category : 6:;tirements.
9 Normal Makeup to This penetratico does not serve as RC Systen a post-LOCA Cot tainment isolation function. Thit is the charging line for the HPI system and is opened after a LOCA.
10 RCP Seal Injec-Same as penetration 8.
tion Lines 13 RB Spray Inlet This penetrat:.on does not serve as Line a post-LOCA Containment isolation function.
Flc,w through penetration is required f311owing a LOCA to pro-vide RBS.
Piping upstream of pene-tration is filled with water, and pressurized Above Containment pressure and is seism;.c Category I.
14 R3 Spray Inlet Same as penetration 13.
15 LPI Decay Heat This penetration doas not serve as Removal Line a post-LOCA Containment isolation function. The LP system upstream of penetration is filled with water, in operation ar a pressure greater than-containment pressure and meets seismic Category I requirements.
.g Mr. Edson G. COCO,
,ing Dirccter Prga Fcur S:ptemb:r 14, 1977 Penetration Description Basis for Classification 16 LPI Decay Heat Same as penetration 15.
Removal Line 17 Emergency Feed-This penetration does not serve as water Inlet Line post-LOCA Containment isolation function because the secondary side of each OTSG and connected systems are considered to be an extension of Containment. This line is pressurized above post-LOCA RCS pressure and meets seismic Category I requirements.
23 RCP Seal Injec-Same as penetration 10.
tion Lines 25 & 27 Feedwater Lines Same as penetration 17.
26 & 28 Steam Lines Same as penetration 17.
Additionally, main steam stop valves are leak tested annually per Technical Specification 4.8.2.
30 RB Emergency These penetrations do not serve as 31 Cooler Inlet a containment isolation function;
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32 Lines flow through these penetrations is required fcilowing a LOCA to provide RB cooling.
Piping upstream of pene-tration is filled with water, and pressurized above containment pressure and is seismic Category I.
33 RB Emergency Same as penetration 30.
34 Cooler Inlet 35 Line 36 RB Sump Recire These penetrations do not serve a 37 Line Containment isolation function; flow through these penetrations is required for long term cooling. Additionally, these penetrations are leak tested annually per Technical Specification 4.5.4.2.
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50 Emergency Feed-Same as penetration 17.
water Inlet Line 52 Emergency Reactor Same as penetration 9.
Injection Line
Mr. Edson G. Caco,
).ingDircctor
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-Pcg2 Fiva Snptemb:r 14, 1977 Penetration Description Basis for Classification 57 Decay Heat or This penetration does not serve a 4
Fuel Transfer Containment isolation function.
Canal Outlet Upstream of penetration piping is Line seismic Category I and cone?" ' to emergency sump suction line.
With regard to the testing of containment airlocks (personnel and emergency hatches), our letter of February 15, 1977 provided information which de-monstrated that the present design of the airlocks prevented meeting either the literal regulations or the staff interpretation prosided by Mr. A.
Schwencer's letter of November 23, 1976._
l The personnel and emergency airlocks provide a mechanism for personnel l
and material passage into or out of reactor containment while maintaining containment integrity. Most airlock designs are similar in hat an innar and outer door are provided, both arranged to seat with Reactor Building pressure.
In order to perform the Type B leak rate test required by l
Appendix J, the volume between the inner and outer doors must be pressurized to design pressure.
This tends to seat the outer airlock door while un-j seating the inner door.
Therefore, restraints are placed on the airlock side of the inner door to physically restrain the door from lifting off 1
its seat while the volume between the doors is pressurized. After a leak rate has been established and the test completed, the airlock outer door must be opened to remove the restraints on the inner door in order to per-mit rapid emergency access to containment should it be necessary. The opening of the outer door negates the preceding test since Appendix J re-quires an airlock-test each time the airlock has been opened.
Airlock tests performed on a six-month basis are adequate to verify the integrity of the airlock.
An airlock Type B test requires several hours to perform since the entire airlock ;ust be pressurized to the design pressure and a leak rate be es-tablished. Appendix J does not specify under which unit conditions the air lock should be tested. Thus, although entry to the Reactor Building is normally somewhat restricted during operation, entry for maintenance while the unit is in a hot or cold shutdown-condition is frequent.
It would be impossible to accomplish plant operation or maintenance if a test of the airlock is required after each entry. This is due to the-large-number of entries to the Reactor-Building and the period of time necessary for the test.
It has been explained that the reason this requirement exists in the regulations is because of the relatively large probability of inadvertantly damaging the door seals during personnel passage.
It has been our experi-ence during ever four years of operation that the seals have not become damaged due to this mechanism.
Indeed, the majority of failures have
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m Mr. Edson G. Coco,r 3._, ting Dircettr
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P ga Six
.. S:ptemb:r 14, 1977 occurred as a result of testing the inner door seal in a direction opposite to that of accident pressure. NRC staff guidelines and in-terpretations which relax the testing requirements to "within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of the first of a series of openings" and relax the requirements to permit testing between the dual seals of a door at reduced pressure do not appear to be consistent with the regulations.
It is considered that testing of airlocks on a six-month basis will be adequate to verify operability.
The test after each opening is not possible based upon equipment design and is not practical based upon operating experience.
Modifications to the airlocks in order to meet the regulations or the staff interpretation of the regulations would require extensive back-fitting.
It is our opinion that these modifications will not provide substantial, additional protection for the public health and safety or the common defense and are therefore not justifiable.
We continue to request an exemption to Appendix J in this regard.
If an exemption is not granted, we reserve the right to Lunediately petition for a rule change pursuant to 10CFR2.
Very truly yours,'
, Q u ~ i.).*ct~
V-William O. Parker, J',)
s RLG:ge
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