ML20084S561
| ML20084S561 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/17/1984 |
| From: | Zimmerman S CAROLINA POWER & LIGHT CO. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.16, TASK-TM NLS-84-215, NUDOCS 8405250208 | |
| Download: ML20084S561 (3) | |
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Cp&L Carolina Power & Light Company SERIAL: NLS-84-215 MAY 171984 Director of Nuclear. Reactor Regulation Attention:
Mr. D. B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing United States Nuclear Regulatory Commission Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION NUREG-0737, ITEM II.K.3.16
Dear Mr. Vassallo:
In your letter dated March 12, 1984, Carolina Power & Light Company (CP&L) was requested'to provide information concerning our submittal concerning NUREG-0737, Item II.K.3.16.
Attached are CP&L's responses to the questions raised by your staff.
Should you have any questions concerning this matter, please contact Mr. Mark A. Turkal at (919) 836-8169.
Yours very truly, s
me-S.
.Z erman nager Nuclear Licensing Section MAT /ccc (037 MAT)
Attachment cci Mr. D. O. Myers (NRC-BSEP)
Mr. J. P. O'Reilly (NRC-RII)
Mr. H. Crotenhuis (NRC) 411 Fayetteville Street e P. O. Box 1551
- Raleigh, N. C. 27602 g
9495250208 840517
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S RESPONSES TO NRC QUESTIONS CONCERNING NUREG-0737, ITEM II.K.3.16
- 1) Which, if any, of the staff recommended modifications have been implemented?
Response
The BWR Owners' Group made an evaluation of the potential benefit of various design changes for reducing the likelihood of a stuck open relief valve event. CP&L concurred with findings of the BWR Owners' Group that replacing three stage Target Rock Safety / Relief Valves with two stage valves and incorporation of the manual equivalent of the low-low set relief concept into new emergency instructions would achieve the goal of an order of magnitude reduction in probability of a stuck open relief valve event.
Plant Modification Nos.80-085 and 80-086 were implemented on Brunswick Units 1 and 2, respectively, to change out three stage Target Rock Safety / Relief Valves with two stage top-work relief valves. The manual equivalent of the low-low relief concept is included in CP&L's Emergency Procedure EI-31.
- 2) Which, if any, of the staff recommended modifications do your propose to implement?
Response
CP&L's position on each of the staff recommended modifications is discussed below:
a.
Low-Low Set (LLS) Ralief Logic System or Equivalent Manual Actions As discussed above, the equivalent manual action has been implemented.
b.
Lower the reactor pressure vessel water level isolation setpoint for main steam isolation valve closure from Level 2 to Level 1.
This modification is being reviewed as a part of the ongoing Torus Integrity Program.
c.
Increase safety / relief valve simmer margin.
The setpoints on the three stage top-work valves were modified prior to replacement by the two stage top-work valves. The higher setpoints were maintained on the two stage safety relief valves after replacement.
In the case of the two stage Target Rock safety / relief valves, pilot valve leakage does not lead to spurious opening. The BWROG study concluded that increasing simmer margins would not cause any significant reduction in safety relief valve challenges for the two stage Target Rock valves.
(037 HAT /ccc)
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Preventive Maintenance Program CP&L is working with the BWROG, GE, and Target Rock on problems associated with Target Rock safety / relief valves. Brunswick has established a policy of complying with vendor recommendations concerning the valves or providing justification when deviation is necessary. At the recommendation of GE and the BWROG, all safety relief valves on a unit are being removed and tested during that unit's refueling outage. When it is justified, the testing frequency of the safety relief valves will be restored to that established in ASME Section XI, Subsection IWV.
- 3) Have you impicmented or proposed to implement any of the other modifications or actions discussea in NUREG-0737, Item II.K.3.16 or in the BWR Owners' Group report?
Response
CP&L considers the actions discussed above sufficient to resolve Item II.K.3.16.
Accordingly, none of the other modifications or actions shall be implemented.
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(037 MAT /ccc) 1
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