ML20247B756

Advises That Response to Generic Ltr 88-17 Re Expeditious Actions for Loss of DHR Acceptable.Training Program Should State That Maint Personnel Included in Program & Daily Walkdowns of Tygon Tube Areas Should Be Performed

ML20247B756
Person / Time
Site:	Rancho Seco
Issue date:	09/06/1989
From:	Reynolds S Office of Nuclear Reactor Regulation
To:	Keuter D SACRAMENTO MUNICIPAL UTILITY DISTRICT
References
GL-88-17, TAC-69769, NUDOCS 8909130132
Download: ML20247B756 (5)

Text

--- - - -

,  ;}

pu TicQ '

'l 4 ,o UNITED STATES

4 g g(

E NUCLEAR REGULATORY COMMISSION 3 WASHINGTON, D. C. 20555

! I' e r . -

September 6, 1989 Docket No. 50-312 i

Mr. Dan Keuter Assistant General Manager, Nuclear l Sacramento Municipal Utility District

~P.O. Box-15830 Sacramento,' California 95852-1830

SUBJECT:

RESPONSE TO GENERIC LETTER 88-17 WITH RESPECT TO EXPEDITIOUS ACTIONS FOR LOSS OF DECAY HEAT REMOVAL FOR RANCHO SECO (TACNO.69769)

Generic L'etter (GL) 88-17 was issued on October 17, 1988 to address the potential for loss of ' decay heat removal (DHR) during nonpower operation. -In the GL, the NRC requested (1)'a description of efforts to implement the eight recommended expeditious actions of the GL and (2) a description of the enhancements, specific

. plans'and.a schedule for implementation of the six recommended program enhance-ments.

The NRC staff has reviewed your response to Generic Letter 88-17 on expeditious actions-in your letter of January 31, 1989. Your letter also included responses for programmed enhancements. However, these will be reviewed at a later time and addressed in a separate letter. The NRC staff finds that your response is generally complete and appears to meet the intent of the generic letter with respect to expeditious actions. However, in a few areas, your response is sufficiently vague that we cannot fully understand your actions taken in response to GL 88-17. We request that you review the following observations in order to assure yourselves that the actions are adequately addressed:

1. You have provided a general description of the training related to loss of DHR for Operations personnel and continued cyclic requali-fication training for reduced inventory operation, where lowered loop operations are anticipated, with licensed individuals of your staff. While your training program appears to be comprehensive, it does not specifically state that maintenance personnel are also included in any of the training. The item was intended to include all personnel who can affect reduced inventory operation.

2. fou indicate that a detailed analysis is being performed for the time available to achieve containment closure. In the meantime, before plant specific times are obtained, you have not presented any times for containment closure. Generic Letter 88-17 states that " containment penetrations including the equipment hatch, may remain open provided closure is reasonably assured within 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of initial loss of DHR."

OFof I t 8909130132 890906 I

PDR ADOCK 05000312 A___ _ _ ___

PDC ,

r Mr. Din'Keuter September 6, 1989

3. In some plants the quick closure of the equipment hatch is achieved

. by the installation of a reduced number of bolts. If you plan to-use less than the full complement of bolts for sealing the equipment' hatch then you:should first verify that you can make a proper seal.

of the periphery mating surfaces to meet the closure criteria.

4 You state that you have'one hot leg level instrument for each of the l

two loops and.that the level readings can be monitored in the control

- room by either the Safety Parameter Display System (SPDS) or Interim Data Acquisition and Display System (IDADS). However, you state that these:1evel indications are affected by the,DHR system flow rate (dynamic head) and are therefore not provided with a low level alarm function.. The range of'the level instruments is given as 0 to 644 inches of water, with the zero point being the bottom.of the hot leg.

You have not stated what type of level instruments are being used, where the taps are, .the accuracy'or the frequency of recording. You havestatedthatthereisalsoacoldleglevelindication(L202)-

which has alarm capability. No information is provided on the; type of this level instrument . its range, tap locations or accuracy. If the L202 indication.is . lost, you state that a local level tube can be manually valved in and a TV camera can be focused on the. level-tube for viewing in the' control room or an individual will be stationed at the level tube with direct communication with the control room when reduction in inventory is in progress. When the alarm function is not available you state that the level reading will be recorded every 15 minutes. You have not stated the type of this level instrument but it appears likely to be a-tygon tube. Also, its tap locations and accuracy are not provided. When two or more level instruments are in place, care should be taken to resolve any dis-crepancy between the measurement systems. Also, the pressure of the reference leg should approximate the pressure of the void in the hot.

' leg or be compensated to obtain the correct level value, j

5. One of-your level measurement instruments, referred to as a level tube, appears to be a tygon tube. Walking the tygon tube following installa-tion to verify lack of kinks Jr loop seals is necessary. Experience shows that periodic walkdowns are needed after installation. We recommend daily walkdowns when the tygon tube is in use, with an additional walkdown immediately prior to its being placed in use.

6.- Regarding procedures and administrative controls on precautions to avoid conditions which could result in system instabilities while in a reduced inventory condition, you have referred tc your Procedure A.1 " Reactor Coolant System." You state that it provides detailed instructions but have not provided a brief explanation of what items are covered.

7. For the expeditious action regarding provision of at least two avail-able or operable means of adding inventory to the RCS that are in addition to pumps that are a part of the normal DHR systems, you have l

4

' fe . September 6, 1989 Mr. Dan Keuter .-

l provided information on two neans. The primary means is gravity drain from the Borated kater Storage Tank (BWST) to the RCS. The second means is a high pressure injection / makeup pump. You have not describec the injection paths. When using gravity drain from L the BWST a proper means for venting must be in place and verified by calculations (see next item).

l

8. You have not stated the use of vent openings on the hot side of the RCS to relieve RCS pressurization. Calculations need to be performed to verify the effectiveness of RCS openings; however, because even for relatively large hot side openings in the RCS, pressurization to several psi can still result. For example, with removal of a pressurizer manway large steam flows in combination with flow restrictions in the surge line and lower pressurizer hardware m6y still lead to pressurization.

As you are aware, the expeditious actions you have briefly described are an intertia measure to achieve an inmediate reduction in risk associated with reduced inventory operation, and these will be supplemented and in sone cases replaced by progranmed enhancements. We intend to audit both your response to the expeditious actions and your programmed enhancement program. The areas where we do not fully understand your responses as indicated above may be covered in the audit of expeditious actions.

Sincerely, O d Steven A. Reynolds, Project Manager Froject Directorate V Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear Reactor Regulation cc: See next page

r - .___ _

.Mr.'D'an Keuter <

provided information on two means. The primary means is gravity drain from the Borated Water Storage Tank (BWST) to the RCS. The second means is a high pressure injection / makeup pump. You have not described the injection paths. When using gravity drain from the BWST a proper means for venting nust be in place and verified by calculations (see next item).

8. You have not stated the use of vent openings on the hot side of the RCS to relieve RCS pressurization. Calculations need to be performed to verify the effectiveness of RCS openings; however, because even for relatively large hot side openings in the RCS, pressurization to several psi can still result. For example, with removal of a pressurizer manway large steam flows in combination with flow restrictions in the surge line and lower pressurizer hardware may still lead to pressurization.

As you are. aware, the expeditious actions you have briefly described are an interim measure to achieve an immediate reduction in risk associated with reduced inventory operation, and these will be supplemented and in some cases replaced by programmed enhancements. We intend to audit both your response to the expeditious actions and your programmed enhancement program. The areas where we do not fully understand your responses as indicated above may be covered in the audit of expeditious actions.

Sincerely, original signed by Steven A. Reynolds Steven A. Reynolds, Project Manager Project Directorate V Division of Reactor Projects - III, IV, Y and Special Projects Office of Nuclear Reactor Regulation cc: See next page DISTRIBUTION p~;'~ Docket File; '

HBalukjian JLee NRC & LPDRs OGC SReynolds PD5 Reading EJordan GKalman MVirgilio BGrimes ACRS(IC: SRichards, Region V

[RSTAC69769]

/PD5 DRSP/PD5 - PDS D5 SReynol s:dr jKalman h on 8/ 89 8/30/89 f/f/89 / /89 C --- -

g' Mr.*D'en Keuter. Rancho Seco Nuclear Generating Station cc:

Ms. Jan Schori, General Manager Mr. John Bartus Sacramento Municipal Utility District Ms. JoAnne Scott 6201 S Street Federal Energy Regulatory Comission P.O. Box 15830 825 North Capitol Street, N. E.

Sacramento, California 95813 Washington, D.C. 20425 Thomas A. Baxter, Esq. Ms. Helen Hubbard Shaw, Pittman, Potts & Trowbridge P. O. Box 63 2300 N Street, N.W. Sunol, California 94586 Washington, D.C. 20037 Environmental Conservation Mr. Steven Crunk Organization Manager, Nuclear Licensing Suite 320 Sacramento Municipal Utility District 101 First Street Rancho Seco Nuclear Generating Station Los Altos, California 94022

'14440 Twin Cities Road Herald, California 95638-9799 Mr. Robert B. Borsum, Licensing Representative Babcock & Wilcox Nuclear Power Division 1700 Rockville Pike - Suite 525 Rockville, Maryland 20852 Resident inspector / Rancho Seco c/o U. S. N. R. C.

14440 Twin Cities Road Herald, California 95638 Regional Administrator, Region Y U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Mr. John Hickman Senior Health Physicist Environmental Radioactive Management Unit Environmental Management Branch State Department of Health Services 714 P Street, Room 616 Sacramento, California 95814 l Sacranento County Board of. Supervisors 700 H Street, Suite 2450 Sacramento, California. 95814 (11)

__-_ __.