ML20040B266
| ML20040B266 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 01/07/1982 |
| From: | Morisi A BOSTON EDISON CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.15, TASK-TM 82-3, NUDOCS 8201250332 | |
| Download: ML20040B266 (2) | |
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BOSTON EpisON COMPANY DENERAL OFFICEE B00 BovLaTON STREET D asTON. M AS SACH U B ETTs 02199 4
A. V. M O RIBI i
MANAGER 1
NUCLEAR OPERATIONS SUPPORT DEPARTMENT t
J January 7, 1982 BECo Ltr. #82-3 cc Mr. Thomas A.
Ippolito, Chief F
D Operating Reactors Branch #2 Division of Licensing ngcGVED Office of Nuclear Reactor Regulation U.S..iuclear Regulatory Commission 9-tg g g jg> -)) 1 Washington, D.C.
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!j NUREG 0737, Item II.K.3.15 1
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Reference:
(a) BEco Letter #80-310, (A.
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to NRC (D. G. Eisenhut) dated December 15, 1980 j
Dear Sir:
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In your letter of October 7, 1981, you requested that Boston Edison Company i
(BECo) submit additional information for NUREG 0737, Item II.K.3.15, "High Pres-f sure Coolant Injection and Reactor Core Isolation Cooling System" pipe-break l
detection logic modifications. As stated in our initial response, Ref. (a),
BECo has elected to employ the BWR Owners Group modification which incorporates a time delay relay (TDR) to eliminate spurious isolation of the HPCI and/or RCIC systems due to a pressure spike which could accompany an abnormal system j
start-up.
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Additional information requested in your October 7, 1981 letter is submitted j
as follows:
j J
j ITEM #1 1
Assurance that the pipe-break detection logic has been modified such that I
pressure spikes resulting from initiation of HPCI and/or RCIC do not cause spurious system isolation, s
j RESPONSE #1 4
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Boston Edison believes that the probability of spurious trips due to pressure t
spikes resulting from initiation of HPCI and/or RCIC is remote as demonstrated by PNPS 1 plant operating history. However, PNPS 1 has elected to install a 3 second i
j (nominal) time delay relay to provide added assurance that such trips will not occur in the future.
This modification is currently being installed and post-installation testing will be performed to verify that the change will prevent spurious isolation i
during system initiation.
Boston Edison believes that this testing along with normal surveillance testing, will provide ongoing assurance that such trips will not occur 4
at PNPS 1.
8201250332 820107 0
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PDR ADOCK 05000293 p
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BOSTON EDISDN CO M PANY January 7,
1982 Page 2 ITEM !/2 Acceptability of the proposed Technical Specifications necessary to implement the modification (eg. surveillance on time delay relay setting, flow or response time set point changes, etc.)
RESPONSE #2 Boston Edison does not believe that this modification necessitates Technical Specification changes. As stated in PNPS Technical Specifications, page 62, TABLE 4.2.B " Minimum Test and Calibration Frequency for CSCS", Items 5 and 7 makes re ference to table Note 6.
Note 6 states that "The logic system functional tests shall include a calibration of delay relays and timers necessary for proper functioning of the trip system".
The new time delay relays will be tested by this requirement.
Ilowever, Boston Edison intends to modify surveillance test acceptance criteria for llPCI and RCIC isolation valve closure times to reflect the 3 second time delay (ie Closure time for IIPCI steam isolation valves will be reduced to 22 seconds vice 25 seconds).
ITD1 t!3 No degradation of the safety f unction of the primary system isolation due to the modification.
RES PONS E # 3 Boston Edison has performed a plant specific safety evaluation on incorporation of a 3 second (nominal) time delay relay into llPC1/RCIC break detection logics.
This evaluation has resulted in the following conclusions :
1)
"... implementing a three-to-five second TDR for both IIPCI and RCIC break detection circuitry is considered adequate to prevent spurious isolat ion signals under auto-s tart conditions."
2)
"Furthermore. implementation of this preventive measure does not adversely affect the plant transient expected as a result of an llPCI or RCIC steam line break".
We trust this letter is responsive to your request however, should you desire additional information or clarification please feel free to contact us.
Very truly yours, 0<
M. -
s-a m i