ML18093B477

Requests Discretionary Enforcement Re Action Statement for Limiting Condition for Operation 3.6.2.1, Containment Spray Sys, to Provide Addl 4-day Period Beyond Expiration of Current Action Statement to Restore Sys to Operability

ML18093B477
Person / Time
Site:	Salem
Issue date:	03/03/1989
From:	Labruna S Public Service Enterprise Group
To:	Russell W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 8903140310
Download: ML18093B477 (10)

Text

Public Service Electric and Gas Company Stanley LaBruna Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-4800 Vice President - Nuclear Operations V;irch 3, 19f.9 W. T. Russell, Ad~inistrator.

NRC Region I 475 Allendale Rd.

King of Prussia, PA 19406 Gentlemen:

REQUEST FOR DISCRETIONARY ENFORCEMENT TECHNICAL SPECIFICATION 3.6.2.1 SALEM GENERATING STATION FACILITY OPERATING LICENSE NO. DPR-75 UNIT NO. 2 DOCKET NO. 50-311 Public Service Electric and Gas Company (PSE&G) hereby requests discretionary enforcement with regard to the Action Statement for the Limiting Condition for Operation (LCO) 3.6.2.1, Containment Spray System, of the Salem Generating Station Unit No. 2 Technical Specifications. As discussed in Attachment 1, plant operation subsequent to the granting of this relief request would not create a significant hazard to public health and safety and is justified on technical and economic bases. The requested relief would provide an additional "4-day period beyond the expiration of the current action statement allowance in which to restore the affected Containment Spray System train to an operable condition.

This request has.become necessary due to the existence of through-wall pinhole leaks on a section of piping on the discharge side of the 21 Containment Spray Pump, rendering the associated containment spray train inoperable.

Within 14 days of our compliance with the requirements of the subject specification, PSE&G will submit a special report identifying all corrective*actions taken.

8903140310 OQO~O~

PDR ADOCK 5§656~11 p PDC

2 Your timely assistance is requested, via a verbal approval of this request by 6:00 a.m., Monday, March 6, 1989, in order to avert an unnecessary plant shutdown as detailed herein. If you have questions, we will be pleased to discuss them with you.

Sincerely Stanley LaBruna Vice President -

Nuclear Operation Enclosures C Mr. J. C. Stone Licensing Project Manager - Salem Ms. K. Halvey Gibson Senior Resident Inspector - Salem Ms. J. Moon, Interim Chief New Jersey Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, N.J. 08625 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Ref* REQUEST FOR DISCRETIONARY ENFORCEMENT - SGS, UNIT 2 STATE OF NEW JERSEY SS.

COUNTY OF SALEM Stanley LaBruna, being duly sworn according to law deposes and says:

I am Vice President - Nuclear Operations of Public Service Electric arid Gas Company, and as such, I find the matters set forth in our letter dated March 3, 1989, concerning Facility Operating License DPR-75 for Salem Generating Station, Unit No. 2, true to the best of my knowledge, information and belief.

~7 7 Subscribed and Sworn to before me this 3rd day of (Y/Cl/Ycfv , 19 8 9

~-\L **:~ : *'*' ... *-=-

My Commission expires on NOTARY;--'.:;~, 'i:-; : .

, :... :*.~

TTr"ACHMENT 1 TECHNICAL SPECIFICAT~ON 3.6.2. CONTAINMENT SPRAY SYSTEM Tee hnical Speci fie a tion Limiting Condi ti on for Operation (JJCO) 3.6.2.1. identifies the operability requirements for the Salem Unit 2 Containment Spray System. The containment Spray System consists of two independent spray systems with each system capable of taking suction from the RWST and transferring suction to the RHR pump discharge for the purpose of containment depressurization and cooling capability in the event of a LOCA. The containment Spray System also provides a mechanism for removing iodine from the containment atmosphere via a common spray additive tank which inputs sodium hydroxide to the spray system via an eductor.

The Action Statement for LCO 3.6.2.1 indicates that one train of the Containment Spray System may be out of service for a period of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

SUMMARY

of CURRENT SITUATION At 6:00 a.m. on Friday, March 3, 1989, during the performance of a valve surveillance in the mechancial penetration area, a series of pinhole leaks were noted on a portion of piping on the discharge side of the 21 Containment Spray Pump. Further investigation revealed the leaks to be coming from a formed portion of 8" pipe between check valves 21CS4 and 21CS48 on the discharge side of the pump. The formed section of pipe appeared to be discolored around 1

Statement deadline of 6:00 a.m., Monday March 6, 1989 requiring a plant shutdown from 100% of rated power. PSE&G therefore requests that NRC Region I grant discretionary enforcement of the Action Statement for LCO 3.6.2.1 of the Salem Unit 2 Technical Specifications for a period that would allow an additional 4 days, beyond the presently allowed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, to complete the restoration of the 21 Containment Spray train to operable status by replacement of the affected piping.

PSE&G believes that this extension of time will not place the plant in an unsafe condition since the availability of the other containment spray train and the containment fan coil units meet plant design considerations regarding containment pressure reduction and iodine removal in the event of a LOCA. This is discussed in detail in the technical justification presented below.

PSE&G belives that this occurrence represents a situation which was beyond our control and could not have been foreseen since the piping run is not part of the ISI program and justifies this request for discretionary enforcement.

Operation under the requested discretionary enforcement will not place the plant in an unsafe condition. PSE&G belives that there is ample technical justification for the requested relief, as described in the following paragraphs.

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the area where the pinhole leaks had occurred.

Visual and ultrasonic examination was subsequently performed in an attempt to determine the failure mechanism. As a result of the NDE performed, PSE&G believes that the portion of piping was sensitized due to the forming operation, making it susceptible to pitting attack. The existence of stagnant borated water may also have contributed to the corrosion mechanism.

PSE&G has performed a walkdown on the analogous portions of piping on the discharge of the 22 Contaiment Spray Pump. This walkdown revealed that there was no dicoloration of the piping and that the piping run was considerably straighter than that on which the pinhole leaks were encountered. PSE&G has planned-an ultrasonic examination of the like portion of the 22 contaiment spray train piping to ensure that similar deterioration has not occurred.

PSE&G will also walkdown the like portions of piping of the Salem Unit 1 Containment Spray System for any similarity. The need for NDE on the Unit 1 piping will be evaluated based on the results of the walkdowns.

Salem Generating Station plant management is concerned that repair efforts on the affected portion of the 22 Containment Spray System Piping will extend beyond the current 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> LCO 3.6.2.1 Action 2

~~stification that the request will not create a significant hazard to publ~c he~lth & safety.

Extension of the allowed outage time for one train of containment spray has been evaluated for impact to the public health and safety. The following paragraphs address identified concerns.

The failure mechanism has been tentatively identified to be internal pitting caused by a combination of sensitization of the piping due to the spool piece forming process coupled with stagnant borated water trapped in the piping during testing due to a dowmsteam check valve. The alternate train does not have similar bends and thus were not formed in the same manner and were not sensitized. This is confirmed by the presence of heat discoloration on the leaking pipe which is not present on the opposite train~ No sign of leakage was observed during visual inspection of the opposite train. Walkdowns were performed on both units piping in the area affected by the pitting. No indication of leaking was observed. Additional NDE is being performed on Unit 2 to confirm that the failure mechanism is 4

limited to a small section of piping. Any indications to the contrary will cause reevaluation of our plans. Based on the preliminary indications, the affected area is limited and not indicative of a widespread failure mechanism.

A Probabilistic Risk Analysis (PRA) has been performed to determine the affect of extending the allowed outage time from 3 to 7 days on the increase in the probability of a core melt. The analysis assumed one train out of service for 7 days, the alternate train subject only to random failure and 3 containment fan coil units available. The results of this analysis indicate that the increase in the probability of core melt is approximately 2xl0 -8 /yr or approximately 1/100 of 1% of the total core melt probability. This is considered to be insignificant increase in the core melt probability and will not significantly affect public health and safety.

The basis of the Technical Specification for availability of the core spray system is two fold. First it is a portion of th~

equipment necessary for control of contaiment pressure. The UFSAR basis for pressure control requires any combination listed below:

1. Two containment spray systems, or

2. One containment spray and three containment fan coil unit, or

3. Five containment fan coil units 5

Technical Specifications require 5 fan coil units to be operable.

Currently the 5 fan coil units are operable. Therefore with the remaining containment spray system operable, the containment pressure control requirement is satisfied.

The second function of the spray system is iodine removal from the containment steam atmosphere duing a LOCA. The UFSAR states that this function is satisfied with one spray system operable. In the extremely unlikely event of a LOCA during this 7-day period, coupled with failure of the second spray system, the impact to thyroid doses to the public has been evaluated. The UFSAR indicates that a partition factor of 100 is applied due to the effect of the spray system. Thyroid doses at the site boundary assuming the spray system is operable is .028 rem. If the partition factor is not applied, a 100 fold increase results.

This yields a thyroid dose of 2.8 rem. The 10CFR 100 dose limit to the thyoid is 300 rem. Therefore the dose increase does not represent a significant risk to the health and safety of the public.

Additionally there is industry precedent for extension of the action statement from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days. The Byrom and Braidwood stations has received License Amendments allowing permanent extension of the action statement to 7 days. This amendment was issued January 21, 1988.

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Based on the above reasons it is concluded that extending the action statement from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days for outage of one containment spray system will not cause a significant hazard to the public health and safety.

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